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![Qian Cai](/assets/img/avatar_default.png)
set_zspage_inuse() was introduced in the commit4f42047bbd
("zsmalloc: use accessor") but all the users of it were removed later by the commits,bdb0af7ca8
("zsmalloc: factor page chain functionality out")3783689a1a
("zsmalloc: introduce zspage structure") so the function can be safely removed now. Link: http://lkml.kernel.org/r/1568658408-19374-1-git-send-email-cai@lca.pw Signed-off-by: Qian Cai <cai@lca.pw> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2587 lines
62 KiB
C
2587 lines
62 KiB
C
/*
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* zsmalloc memory allocator
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*
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* Copyright (C) 2011 Nitin Gupta
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* Copyright (C) 2012, 2013 Minchan Kim
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*
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* This code is released using a dual license strategy: BSD/GPL
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* You can choose the license that better fits your requirements.
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*
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* Released under the terms of 3-clause BSD License
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* Released under the terms of GNU General Public License Version 2.0
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*/
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/*
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* Following is how we use various fields and flags of underlying
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* struct page(s) to form a zspage.
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*
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* Usage of struct page fields:
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* page->private: points to zspage
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* page->freelist(index): links together all component pages of a zspage
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* For the huge page, this is always 0, so we use this field
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* to store handle.
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* page->units: first object offset in a subpage of zspage
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*
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* Usage of struct page flags:
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* PG_private: identifies the first component page
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* PG_owner_priv_1: identifies the huge component page
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*
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/magic.h>
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#include <linux/bitops.h>
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#include <linux/errno.h>
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#include <linux/highmem.h>
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#include <linux/string.h>
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#include <linux/slab.h>
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#include <asm/tlbflush.h>
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#include <asm/pgtable.h>
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#include <linux/cpumask.h>
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#include <linux/cpu.h>
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#include <linux/vmalloc.h>
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#include <linux/preempt.h>
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#include <linux/spinlock.h>
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#include <linux/shrinker.h>
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#include <linux/types.h>
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#include <linux/debugfs.h>
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#include <linux/zsmalloc.h>
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#include <linux/zpool.h>
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#include <linux/mount.h>
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#include <linux/pseudo_fs.h>
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#include <linux/migrate.h>
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#include <linux/wait.h>
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#include <linux/pagemap.h>
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#include <linux/fs.h>
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#define ZSPAGE_MAGIC 0x58
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/*
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* This must be power of 2 and greater than of equal to sizeof(link_free).
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* These two conditions ensure that any 'struct link_free' itself doesn't
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* span more than 1 page which avoids complex case of mapping 2 pages simply
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* to restore link_free pointer values.
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*/
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#define ZS_ALIGN 8
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/*
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* A single 'zspage' is composed of up to 2^N discontiguous 0-order (single)
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* pages. ZS_MAX_ZSPAGE_ORDER defines upper limit on N.
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*/
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#define ZS_MAX_ZSPAGE_ORDER 2
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#define ZS_MAX_PAGES_PER_ZSPAGE (_AC(1, UL) << ZS_MAX_ZSPAGE_ORDER)
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#define ZS_HANDLE_SIZE (sizeof(unsigned long))
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/*
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* Object location (<PFN>, <obj_idx>) is encoded as
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* as single (unsigned long) handle value.
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*
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* Note that object index <obj_idx> starts from 0.
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*
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* This is made more complicated by various memory models and PAE.
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*/
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#ifndef MAX_POSSIBLE_PHYSMEM_BITS
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#ifdef MAX_PHYSMEM_BITS
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#define MAX_POSSIBLE_PHYSMEM_BITS MAX_PHYSMEM_BITS
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#else
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/*
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* If this definition of MAX_PHYSMEM_BITS is used, OBJ_INDEX_BITS will just
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* be PAGE_SHIFT
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*/
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#define MAX_POSSIBLE_PHYSMEM_BITS BITS_PER_LONG
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#endif
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#endif
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#define _PFN_BITS (MAX_POSSIBLE_PHYSMEM_BITS - PAGE_SHIFT)
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/*
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* Memory for allocating for handle keeps object position by
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* encoding <page, obj_idx> and the encoded value has a room
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* in least bit(ie, look at obj_to_location).
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* We use the bit to synchronize between object access by
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* user and migration.
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*/
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#define HANDLE_PIN_BIT 0
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/*
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* Head in allocated object should have OBJ_ALLOCATED_TAG
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* to identify the object was allocated or not.
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* It's okay to add the status bit in the least bit because
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* header keeps handle which is 4byte-aligned address so we
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* have room for two bit at least.
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*/
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#define OBJ_ALLOCATED_TAG 1
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#define OBJ_TAG_BITS 1
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#define OBJ_INDEX_BITS (BITS_PER_LONG - _PFN_BITS - OBJ_TAG_BITS)
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#define OBJ_INDEX_MASK ((_AC(1, UL) << OBJ_INDEX_BITS) - 1)
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#define FULLNESS_BITS 2
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#define CLASS_BITS 8
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#define ISOLATED_BITS 3
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#define MAGIC_VAL_BITS 8
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#define MAX(a, b) ((a) >= (b) ? (a) : (b))
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/* ZS_MIN_ALLOC_SIZE must be multiple of ZS_ALIGN */
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#define ZS_MIN_ALLOC_SIZE \
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MAX(32, (ZS_MAX_PAGES_PER_ZSPAGE << PAGE_SHIFT >> OBJ_INDEX_BITS))
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/* each chunk includes extra space to keep handle */
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#define ZS_MAX_ALLOC_SIZE PAGE_SIZE
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/*
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* On systems with 4K page size, this gives 255 size classes! There is a
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* trader-off here:
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* - Large number of size classes is potentially wasteful as free page are
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* spread across these classes
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* - Small number of size classes causes large internal fragmentation
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* - Probably its better to use specific size classes (empirically
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* determined). NOTE: all those class sizes must be set as multiple of
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* ZS_ALIGN to make sure link_free itself never has to span 2 pages.
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*
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* ZS_MIN_ALLOC_SIZE and ZS_SIZE_CLASS_DELTA must be multiple of ZS_ALIGN
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* (reason above)
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*/
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#define ZS_SIZE_CLASS_DELTA (PAGE_SIZE >> CLASS_BITS)
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#define ZS_SIZE_CLASSES (DIV_ROUND_UP(ZS_MAX_ALLOC_SIZE - ZS_MIN_ALLOC_SIZE, \
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ZS_SIZE_CLASS_DELTA) + 1)
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enum fullness_group {
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ZS_EMPTY,
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ZS_ALMOST_EMPTY,
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ZS_ALMOST_FULL,
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ZS_FULL,
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NR_ZS_FULLNESS,
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};
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enum zs_stat_type {
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CLASS_EMPTY,
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CLASS_ALMOST_EMPTY,
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CLASS_ALMOST_FULL,
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CLASS_FULL,
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OBJ_ALLOCATED,
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OBJ_USED,
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NR_ZS_STAT_TYPE,
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};
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struct zs_size_stat {
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unsigned long objs[NR_ZS_STAT_TYPE];
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};
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#ifdef CONFIG_ZSMALLOC_STAT
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static struct dentry *zs_stat_root;
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#endif
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#ifdef CONFIG_COMPACTION
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static struct vfsmount *zsmalloc_mnt;
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#endif
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/*
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* We assign a page to ZS_ALMOST_EMPTY fullness group when:
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* n <= N / f, where
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* n = number of allocated objects
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* N = total number of objects zspage can store
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* f = fullness_threshold_frac
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*
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* Similarly, we assign zspage to:
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* ZS_ALMOST_FULL when n > N / f
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* ZS_EMPTY when n == 0
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* ZS_FULL when n == N
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*
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* (see: fix_fullness_group())
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*/
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static const int fullness_threshold_frac = 4;
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static size_t huge_class_size;
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struct size_class {
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spinlock_t lock;
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struct list_head fullness_list[NR_ZS_FULLNESS];
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/*
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* Size of objects stored in this class. Must be multiple
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* of ZS_ALIGN.
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*/
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int size;
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int objs_per_zspage;
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/* Number of PAGE_SIZE sized pages to combine to form a 'zspage' */
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int pages_per_zspage;
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unsigned int index;
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struct zs_size_stat stats;
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};
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/* huge object: pages_per_zspage == 1 && maxobj_per_zspage == 1 */
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static void SetPageHugeObject(struct page *page)
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{
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SetPageOwnerPriv1(page);
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}
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static void ClearPageHugeObject(struct page *page)
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{
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ClearPageOwnerPriv1(page);
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}
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static int PageHugeObject(struct page *page)
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{
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return PageOwnerPriv1(page);
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}
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/*
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* Placed within free objects to form a singly linked list.
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* For every zspage, zspage->freeobj gives head of this list.
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*
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* This must be power of 2 and less than or equal to ZS_ALIGN
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*/
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struct link_free {
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union {
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/*
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* Free object index;
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* It's valid for non-allocated object
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*/
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unsigned long next;
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/*
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* Handle of allocated object.
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*/
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unsigned long handle;
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};
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};
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struct zs_pool {
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const char *name;
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struct size_class *size_class[ZS_SIZE_CLASSES];
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struct kmem_cache *handle_cachep;
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struct kmem_cache *zspage_cachep;
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atomic_long_t pages_allocated;
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struct zs_pool_stats stats;
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/* Compact classes */
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struct shrinker shrinker;
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#ifdef CONFIG_ZSMALLOC_STAT
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struct dentry *stat_dentry;
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#endif
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#ifdef CONFIG_COMPACTION
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struct inode *inode;
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struct work_struct free_work;
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/* A wait queue for when migration races with async_free_zspage() */
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struct wait_queue_head migration_wait;
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atomic_long_t isolated_pages;
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bool destroying;
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#endif
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};
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struct zspage {
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struct {
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unsigned int fullness:FULLNESS_BITS;
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unsigned int class:CLASS_BITS + 1;
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unsigned int isolated:ISOLATED_BITS;
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unsigned int magic:MAGIC_VAL_BITS;
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};
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unsigned int inuse;
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unsigned int freeobj;
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struct page *first_page;
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struct list_head list; /* fullness list */
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#ifdef CONFIG_COMPACTION
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rwlock_t lock;
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#endif
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};
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struct mapping_area {
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#ifdef CONFIG_PGTABLE_MAPPING
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struct vm_struct *vm; /* vm area for mapping object that span pages */
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#else
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char *vm_buf; /* copy buffer for objects that span pages */
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#endif
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char *vm_addr; /* address of kmap_atomic()'ed pages */
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enum zs_mapmode vm_mm; /* mapping mode */
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};
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#ifdef CONFIG_COMPACTION
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static int zs_register_migration(struct zs_pool *pool);
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static void zs_unregister_migration(struct zs_pool *pool);
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static void migrate_lock_init(struct zspage *zspage);
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static void migrate_read_lock(struct zspage *zspage);
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static void migrate_read_unlock(struct zspage *zspage);
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static void kick_deferred_free(struct zs_pool *pool);
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static void init_deferred_free(struct zs_pool *pool);
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static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage);
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#else
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static int zsmalloc_mount(void) { return 0; }
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static void zsmalloc_unmount(void) {}
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static int zs_register_migration(struct zs_pool *pool) { return 0; }
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static void zs_unregister_migration(struct zs_pool *pool) {}
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static void migrate_lock_init(struct zspage *zspage) {}
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static void migrate_read_lock(struct zspage *zspage) {}
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static void migrate_read_unlock(struct zspage *zspage) {}
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static void kick_deferred_free(struct zs_pool *pool) {}
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static void init_deferred_free(struct zs_pool *pool) {}
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static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage) {}
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#endif
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static int create_cache(struct zs_pool *pool)
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{
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pool->handle_cachep = kmem_cache_create("zs_handle", ZS_HANDLE_SIZE,
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0, 0, NULL);
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if (!pool->handle_cachep)
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return 1;
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pool->zspage_cachep = kmem_cache_create("zspage", sizeof(struct zspage),
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0, 0, NULL);
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if (!pool->zspage_cachep) {
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kmem_cache_destroy(pool->handle_cachep);
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pool->handle_cachep = NULL;
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return 1;
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}
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return 0;
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}
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static void destroy_cache(struct zs_pool *pool)
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{
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kmem_cache_destroy(pool->handle_cachep);
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kmem_cache_destroy(pool->zspage_cachep);
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}
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static unsigned long cache_alloc_handle(struct zs_pool *pool, gfp_t gfp)
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{
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return (unsigned long)kmem_cache_alloc(pool->handle_cachep,
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gfp & ~(__GFP_HIGHMEM|__GFP_MOVABLE));
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}
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static void cache_free_handle(struct zs_pool *pool, unsigned long handle)
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{
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kmem_cache_free(pool->handle_cachep, (void *)handle);
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}
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static struct zspage *cache_alloc_zspage(struct zs_pool *pool, gfp_t flags)
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{
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return kmem_cache_alloc(pool->zspage_cachep,
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flags & ~(__GFP_HIGHMEM|__GFP_MOVABLE));
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}
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static void cache_free_zspage(struct zs_pool *pool, struct zspage *zspage)
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{
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kmem_cache_free(pool->zspage_cachep, zspage);
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}
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static void record_obj(unsigned long handle, unsigned long obj)
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{
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/*
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* lsb of @obj represents handle lock while other bits
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* represent object value the handle is pointing so
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* updating shouldn't do store tearing.
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*/
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WRITE_ONCE(*(unsigned long *)handle, obj);
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}
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/* zpool driver */
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#ifdef CONFIG_ZPOOL
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static void *zs_zpool_create(const char *name, gfp_t gfp,
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const struct zpool_ops *zpool_ops,
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struct zpool *zpool)
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{
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/*
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* Ignore global gfp flags: zs_malloc() may be invoked from
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* different contexts and its caller must provide a valid
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* gfp mask.
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*/
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return zs_create_pool(name);
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}
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static void zs_zpool_destroy(void *pool)
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{
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zs_destroy_pool(pool);
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}
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static int zs_zpool_malloc(void *pool, size_t size, gfp_t gfp,
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unsigned long *handle)
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{
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*handle = zs_malloc(pool, size, gfp);
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return *handle ? 0 : -1;
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}
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static void zs_zpool_free(void *pool, unsigned long handle)
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{
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zs_free(pool, handle);
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}
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static void *zs_zpool_map(void *pool, unsigned long handle,
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enum zpool_mapmode mm)
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{
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enum zs_mapmode zs_mm;
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switch (mm) {
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case ZPOOL_MM_RO:
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zs_mm = ZS_MM_RO;
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break;
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case ZPOOL_MM_WO:
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zs_mm = ZS_MM_WO;
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break;
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case ZPOOL_MM_RW: /* fall through */
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default:
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zs_mm = ZS_MM_RW;
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break;
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}
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return zs_map_object(pool, handle, zs_mm);
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}
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static void zs_zpool_unmap(void *pool, unsigned long handle)
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{
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zs_unmap_object(pool, handle);
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}
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static u64 zs_zpool_total_size(void *pool)
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{
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return zs_get_total_pages(pool) << PAGE_SHIFT;
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}
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static struct zpool_driver zs_zpool_driver = {
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.type = "zsmalloc",
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.owner = THIS_MODULE,
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.create = zs_zpool_create,
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.destroy = zs_zpool_destroy,
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.malloc_support_movable = true,
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.malloc = zs_zpool_malloc,
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.free = zs_zpool_free,
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.map = zs_zpool_map,
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.unmap = zs_zpool_unmap,
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.total_size = zs_zpool_total_size,
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};
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MODULE_ALIAS("zpool-zsmalloc");
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#endif /* CONFIG_ZPOOL */
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/* per-cpu VM mapping areas for zspage accesses that cross page boundaries */
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static DEFINE_PER_CPU(struct mapping_area, zs_map_area);
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static bool is_zspage_isolated(struct zspage *zspage)
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{
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return zspage->isolated;
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}
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static __maybe_unused int is_first_page(struct page *page)
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{
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return PagePrivate(page);
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}
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|
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/* Protected by class->lock */
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static inline int get_zspage_inuse(struct zspage *zspage)
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{
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return zspage->inuse;
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}
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static inline void mod_zspage_inuse(struct zspage *zspage, int val)
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{
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zspage->inuse += val;
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}
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static inline struct page *get_first_page(struct zspage *zspage)
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{
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struct page *first_page = zspage->first_page;
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VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
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return first_page;
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}
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static inline int get_first_obj_offset(struct page *page)
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{
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return page->units;
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}
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|
|
static inline void set_first_obj_offset(struct page *page, int offset)
|
|
{
|
|
page->units = offset;
|
|
}
|
|
|
|
static inline unsigned int get_freeobj(struct zspage *zspage)
|
|
{
|
|
return zspage->freeobj;
|
|
}
|
|
|
|
static inline void set_freeobj(struct zspage *zspage, unsigned int obj)
|
|
{
|
|
zspage->freeobj = obj;
|
|
}
|
|
|
|
static void get_zspage_mapping(struct zspage *zspage,
|
|
unsigned int *class_idx,
|
|
enum fullness_group *fullness)
|
|
{
|
|
BUG_ON(zspage->magic != ZSPAGE_MAGIC);
|
|
|
|
*fullness = zspage->fullness;
|
|
*class_idx = zspage->class;
|
|
}
|
|
|
|
static void set_zspage_mapping(struct zspage *zspage,
|
|
unsigned int class_idx,
|
|
enum fullness_group fullness)
|
|
{
|
|
zspage->class = class_idx;
|
|
zspage->fullness = fullness;
|
|
}
|
|
|
|
/*
|
|
* zsmalloc divides the pool into various size classes where each
|
|
* class maintains a list of zspages where each zspage is divided
|
|
* into equal sized chunks. Each allocation falls into one of these
|
|
* classes depending on its size. This function returns index of the
|
|
* size class which has chunk size big enough to hold the give size.
|
|
*/
|
|
static int get_size_class_index(int size)
|
|
{
|
|
int idx = 0;
|
|
|
|
if (likely(size > ZS_MIN_ALLOC_SIZE))
|
|
idx = DIV_ROUND_UP(size - ZS_MIN_ALLOC_SIZE,
|
|
ZS_SIZE_CLASS_DELTA);
|
|
|
|
return min_t(int, ZS_SIZE_CLASSES - 1, idx);
|
|
}
|
|
|
|
/* type can be of enum type zs_stat_type or fullness_group */
|
|
static inline void zs_stat_inc(struct size_class *class,
|
|
int type, unsigned long cnt)
|
|
{
|
|
class->stats.objs[type] += cnt;
|
|
}
|
|
|
|
/* type can be of enum type zs_stat_type or fullness_group */
|
|
static inline void zs_stat_dec(struct size_class *class,
|
|
int type, unsigned long cnt)
|
|
{
|
|
class->stats.objs[type] -= cnt;
|
|
}
|
|
|
|
/* type can be of enum type zs_stat_type or fullness_group */
|
|
static inline unsigned long zs_stat_get(struct size_class *class,
|
|
int type)
|
|
{
|
|
return class->stats.objs[type];
|
|
}
|
|
|
|
#ifdef CONFIG_ZSMALLOC_STAT
|
|
|
|
static void __init zs_stat_init(void)
|
|
{
|
|
if (!debugfs_initialized()) {
|
|
pr_warn("debugfs not available, stat dir not created\n");
|
|
return;
|
|
}
|
|
|
|
zs_stat_root = debugfs_create_dir("zsmalloc", NULL);
|
|
}
|
|
|
|
static void __exit zs_stat_exit(void)
|
|
{
|
|
debugfs_remove_recursive(zs_stat_root);
|
|
}
|
|
|
|
static unsigned long zs_can_compact(struct size_class *class);
|
|
|
|
static int zs_stats_size_show(struct seq_file *s, void *v)
|
|
{
|
|
int i;
|
|
struct zs_pool *pool = s->private;
|
|
struct size_class *class;
|
|
int objs_per_zspage;
|
|
unsigned long class_almost_full, class_almost_empty;
|
|
unsigned long obj_allocated, obj_used, pages_used, freeable;
|
|
unsigned long total_class_almost_full = 0, total_class_almost_empty = 0;
|
|
unsigned long total_objs = 0, total_used_objs = 0, total_pages = 0;
|
|
unsigned long total_freeable = 0;
|
|
|
|
seq_printf(s, " %5s %5s %11s %12s %13s %10s %10s %16s %8s\n",
|
|
"class", "size", "almost_full", "almost_empty",
|
|
"obj_allocated", "obj_used", "pages_used",
|
|
"pages_per_zspage", "freeable");
|
|
|
|
for (i = 0; i < ZS_SIZE_CLASSES; i++) {
|
|
class = pool->size_class[i];
|
|
|
|
if (class->index != i)
|
|
continue;
|
|
|
|
spin_lock(&class->lock);
|
|
class_almost_full = zs_stat_get(class, CLASS_ALMOST_FULL);
|
|
class_almost_empty = zs_stat_get(class, CLASS_ALMOST_EMPTY);
|
|
obj_allocated = zs_stat_get(class, OBJ_ALLOCATED);
|
|
obj_used = zs_stat_get(class, OBJ_USED);
|
|
freeable = zs_can_compact(class);
|
|
spin_unlock(&class->lock);
|
|
|
|
objs_per_zspage = class->objs_per_zspage;
|
|
pages_used = obj_allocated / objs_per_zspage *
|
|
class->pages_per_zspage;
|
|
|
|
seq_printf(s, " %5u %5u %11lu %12lu %13lu"
|
|
" %10lu %10lu %16d %8lu\n",
|
|
i, class->size, class_almost_full, class_almost_empty,
|
|
obj_allocated, obj_used, pages_used,
|
|
class->pages_per_zspage, freeable);
|
|
|
|
total_class_almost_full += class_almost_full;
|
|
total_class_almost_empty += class_almost_empty;
|
|
total_objs += obj_allocated;
|
|
total_used_objs += obj_used;
|
|
total_pages += pages_used;
|
|
total_freeable += freeable;
|
|
}
|
|
|
|
seq_puts(s, "\n");
|
|
seq_printf(s, " %5s %5s %11lu %12lu %13lu %10lu %10lu %16s %8lu\n",
|
|
"Total", "", total_class_almost_full,
|
|
total_class_almost_empty, total_objs,
|
|
total_used_objs, total_pages, "", total_freeable);
|
|
|
|
return 0;
|
|
}
|
|
DEFINE_SHOW_ATTRIBUTE(zs_stats_size);
|
|
|
|
static void zs_pool_stat_create(struct zs_pool *pool, const char *name)
|
|
{
|
|
if (!zs_stat_root) {
|
|
pr_warn("no root stat dir, not creating <%s> stat dir\n", name);
|
|
return;
|
|
}
|
|
|
|
pool->stat_dentry = debugfs_create_dir(name, zs_stat_root);
|
|
|
|
debugfs_create_file("classes", S_IFREG | 0444, pool->stat_dentry, pool,
|
|
&zs_stats_size_fops);
|
|
}
|
|
|
|
static void zs_pool_stat_destroy(struct zs_pool *pool)
|
|
{
|
|
debugfs_remove_recursive(pool->stat_dentry);
|
|
}
|
|
|
|
#else /* CONFIG_ZSMALLOC_STAT */
|
|
static void __init zs_stat_init(void)
|
|
{
|
|
}
|
|
|
|
static void __exit zs_stat_exit(void)
|
|
{
|
|
}
|
|
|
|
static inline void zs_pool_stat_create(struct zs_pool *pool, const char *name)
|
|
{
|
|
}
|
|
|
|
static inline void zs_pool_stat_destroy(struct zs_pool *pool)
|
|
{
|
|
}
|
|
#endif
|
|
|
|
|
|
/*
|
|
* For each size class, zspages are divided into different groups
|
|
* depending on how "full" they are. This was done so that we could
|
|
* easily find empty or nearly empty zspages when we try to shrink
|
|
* the pool (not yet implemented). This function returns fullness
|
|
* status of the given page.
|
|
*/
|
|
static enum fullness_group get_fullness_group(struct size_class *class,
|
|
struct zspage *zspage)
|
|
{
|
|
int inuse, objs_per_zspage;
|
|
enum fullness_group fg;
|
|
|
|
inuse = get_zspage_inuse(zspage);
|
|
objs_per_zspage = class->objs_per_zspage;
|
|
|
|
if (inuse == 0)
|
|
fg = ZS_EMPTY;
|
|
else if (inuse == objs_per_zspage)
|
|
fg = ZS_FULL;
|
|
else if (inuse <= 3 * objs_per_zspage / fullness_threshold_frac)
|
|
fg = ZS_ALMOST_EMPTY;
|
|
else
|
|
fg = ZS_ALMOST_FULL;
|
|
|
|
return fg;
|
|
}
|
|
|
|
/*
|
|
* Each size class maintains various freelists and zspages are assigned
|
|
* to one of these freelists based on the number of live objects they
|
|
* have. This functions inserts the given zspage into the freelist
|
|
* identified by <class, fullness_group>.
|
|
*/
|
|
static void insert_zspage(struct size_class *class,
|
|
struct zspage *zspage,
|
|
enum fullness_group fullness)
|
|
{
|
|
struct zspage *head;
|
|
|
|
zs_stat_inc(class, fullness, 1);
|
|
head = list_first_entry_or_null(&class->fullness_list[fullness],
|
|
struct zspage, list);
|
|
/*
|
|
* We want to see more ZS_FULL pages and less almost empty/full.
|
|
* Put pages with higher ->inuse first.
|
|
*/
|
|
if (head) {
|
|
if (get_zspage_inuse(zspage) < get_zspage_inuse(head)) {
|
|
list_add(&zspage->list, &head->list);
|
|
return;
|
|
}
|
|
}
|
|
list_add(&zspage->list, &class->fullness_list[fullness]);
|
|
}
|
|
|
|
/*
|
|
* This function removes the given zspage from the freelist identified
|
|
* by <class, fullness_group>.
|
|
*/
|
|
static void remove_zspage(struct size_class *class,
|
|
struct zspage *zspage,
|
|
enum fullness_group fullness)
|
|
{
|
|
VM_BUG_ON(list_empty(&class->fullness_list[fullness]));
|
|
VM_BUG_ON(is_zspage_isolated(zspage));
|
|
|
|
list_del_init(&zspage->list);
|
|
zs_stat_dec(class, fullness, 1);
|
|
}
|
|
|
|
/*
|
|
* Each size class maintains zspages in different fullness groups depending
|
|
* on the number of live objects they contain. When allocating or freeing
|
|
* objects, the fullness status of the page can change, say, from ALMOST_FULL
|
|
* to ALMOST_EMPTY when freeing an object. This function checks if such
|
|
* a status change has occurred for the given page and accordingly moves the
|
|
* page from the freelist of the old fullness group to that of the new
|
|
* fullness group.
|
|
*/
|
|
static enum fullness_group fix_fullness_group(struct size_class *class,
|
|
struct zspage *zspage)
|
|
{
|
|
int class_idx;
|
|
enum fullness_group currfg, newfg;
|
|
|
|
get_zspage_mapping(zspage, &class_idx, &currfg);
|
|
newfg = get_fullness_group(class, zspage);
|
|
if (newfg == currfg)
|
|
goto out;
|
|
|
|
if (!is_zspage_isolated(zspage)) {
|
|
remove_zspage(class, zspage, currfg);
|
|
insert_zspage(class, zspage, newfg);
|
|
}
|
|
|
|
set_zspage_mapping(zspage, class_idx, newfg);
|
|
|
|
out:
|
|
return newfg;
|
|
}
|
|
|
|
/*
|
|
* We have to decide on how many pages to link together
|
|
* to form a zspage for each size class. This is important
|
|
* to reduce wastage due to unusable space left at end of
|
|
* each zspage which is given as:
|
|
* wastage = Zp % class_size
|
|
* usage = Zp - wastage
|
|
* where Zp = zspage size = k * PAGE_SIZE where k = 1, 2, ...
|
|
*
|
|
* For example, for size class of 3/8 * PAGE_SIZE, we should
|
|
* link together 3 PAGE_SIZE sized pages to form a zspage
|
|
* since then we can perfectly fit in 8 such objects.
|
|
*/
|
|
static int get_pages_per_zspage(int class_size)
|
|
{
|
|
int i, max_usedpc = 0;
|
|
/* zspage order which gives maximum used size per KB */
|
|
int max_usedpc_order = 1;
|
|
|
|
for (i = 1; i <= ZS_MAX_PAGES_PER_ZSPAGE; i++) {
|
|
int zspage_size;
|
|
int waste, usedpc;
|
|
|
|
zspage_size = i * PAGE_SIZE;
|
|
waste = zspage_size % class_size;
|
|
usedpc = (zspage_size - waste) * 100 / zspage_size;
|
|
|
|
if (usedpc > max_usedpc) {
|
|
max_usedpc = usedpc;
|
|
max_usedpc_order = i;
|
|
}
|
|
}
|
|
|
|
return max_usedpc_order;
|
|
}
|
|
|
|
static struct zspage *get_zspage(struct page *page)
|
|
{
|
|
struct zspage *zspage = (struct zspage *)page->private;
|
|
|
|
BUG_ON(zspage->magic != ZSPAGE_MAGIC);
|
|
return zspage;
|
|
}
|
|
|
|
static struct page *get_next_page(struct page *page)
|
|
{
|
|
if (unlikely(PageHugeObject(page)))
|
|
return NULL;
|
|
|
|
return page->freelist;
|
|
}
|
|
|
|
/**
|
|
* obj_to_location - get (<page>, <obj_idx>) from encoded object value
|
|
* @obj: the encoded object value
|
|
* @page: page object resides in zspage
|
|
* @obj_idx: object index
|
|
*/
|
|
static void obj_to_location(unsigned long obj, struct page **page,
|
|
unsigned int *obj_idx)
|
|
{
|
|
obj >>= OBJ_TAG_BITS;
|
|
*page = pfn_to_page(obj >> OBJ_INDEX_BITS);
|
|
*obj_idx = (obj & OBJ_INDEX_MASK);
|
|
}
|
|
|
|
/**
|
|
* location_to_obj - get obj value encoded from (<page>, <obj_idx>)
|
|
* @page: page object resides in zspage
|
|
* @obj_idx: object index
|
|
*/
|
|
static unsigned long location_to_obj(struct page *page, unsigned int obj_idx)
|
|
{
|
|
unsigned long obj;
|
|
|
|
obj = page_to_pfn(page) << OBJ_INDEX_BITS;
|
|
obj |= obj_idx & OBJ_INDEX_MASK;
|
|
obj <<= OBJ_TAG_BITS;
|
|
|
|
return obj;
|
|
}
|
|
|
|
static unsigned long handle_to_obj(unsigned long handle)
|
|
{
|
|
return *(unsigned long *)handle;
|
|
}
|
|
|
|
static unsigned long obj_to_head(struct page *page, void *obj)
|
|
{
|
|
if (unlikely(PageHugeObject(page))) {
|
|
VM_BUG_ON_PAGE(!is_first_page(page), page);
|
|
return page->index;
|
|
} else
|
|
return *(unsigned long *)obj;
|
|
}
|
|
|
|
static inline int testpin_tag(unsigned long handle)
|
|
{
|
|
return bit_spin_is_locked(HANDLE_PIN_BIT, (unsigned long *)handle);
|
|
}
|
|
|
|
static inline int trypin_tag(unsigned long handle)
|
|
{
|
|
return bit_spin_trylock(HANDLE_PIN_BIT, (unsigned long *)handle);
|
|
}
|
|
|
|
static void pin_tag(unsigned long handle)
|
|
{
|
|
bit_spin_lock(HANDLE_PIN_BIT, (unsigned long *)handle);
|
|
}
|
|
|
|
static void unpin_tag(unsigned long handle)
|
|
{
|
|
bit_spin_unlock(HANDLE_PIN_BIT, (unsigned long *)handle);
|
|
}
|
|
|
|
static void reset_page(struct page *page)
|
|
{
|
|
__ClearPageMovable(page);
|
|
ClearPagePrivate(page);
|
|
set_page_private(page, 0);
|
|
page_mapcount_reset(page);
|
|
ClearPageHugeObject(page);
|
|
page->freelist = NULL;
|
|
}
|
|
|
|
static int trylock_zspage(struct zspage *zspage)
|
|
{
|
|
struct page *cursor, *fail;
|
|
|
|
for (cursor = get_first_page(zspage); cursor != NULL; cursor =
|
|
get_next_page(cursor)) {
|
|
if (!trylock_page(cursor)) {
|
|
fail = cursor;
|
|
goto unlock;
|
|
}
|
|
}
|
|
|
|
return 1;
|
|
unlock:
|
|
for (cursor = get_first_page(zspage); cursor != fail; cursor =
|
|
get_next_page(cursor))
|
|
unlock_page(cursor);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void __free_zspage(struct zs_pool *pool, struct size_class *class,
|
|
struct zspage *zspage)
|
|
{
|
|
struct page *page, *next;
|
|
enum fullness_group fg;
|
|
unsigned int class_idx;
|
|
|
|
get_zspage_mapping(zspage, &class_idx, &fg);
|
|
|
|
assert_spin_locked(&class->lock);
|
|
|
|
VM_BUG_ON(get_zspage_inuse(zspage));
|
|
VM_BUG_ON(fg != ZS_EMPTY);
|
|
|
|
next = page = get_first_page(zspage);
|
|
do {
|
|
VM_BUG_ON_PAGE(!PageLocked(page), page);
|
|
next = get_next_page(page);
|
|
reset_page(page);
|
|
unlock_page(page);
|
|
dec_zone_page_state(page, NR_ZSPAGES);
|
|
put_page(page);
|
|
page = next;
|
|
} while (page != NULL);
|
|
|
|
cache_free_zspage(pool, zspage);
|
|
|
|
zs_stat_dec(class, OBJ_ALLOCATED, class->objs_per_zspage);
|
|
atomic_long_sub(class->pages_per_zspage,
|
|
&pool->pages_allocated);
|
|
}
|
|
|
|
static void free_zspage(struct zs_pool *pool, struct size_class *class,
|
|
struct zspage *zspage)
|
|
{
|
|
VM_BUG_ON(get_zspage_inuse(zspage));
|
|
VM_BUG_ON(list_empty(&zspage->list));
|
|
|
|
if (!trylock_zspage(zspage)) {
|
|
kick_deferred_free(pool);
|
|
return;
|
|
}
|
|
|
|
remove_zspage(class, zspage, ZS_EMPTY);
|
|
__free_zspage(pool, class, zspage);
|
|
}
|
|
|
|
/* Initialize a newly allocated zspage */
|
|
static void init_zspage(struct size_class *class, struct zspage *zspage)
|
|
{
|
|
unsigned int freeobj = 1;
|
|
unsigned long off = 0;
|
|
struct page *page = get_first_page(zspage);
|
|
|
|
while (page) {
|
|
struct page *next_page;
|
|
struct link_free *link;
|
|
void *vaddr;
|
|
|
|
set_first_obj_offset(page, off);
|
|
|
|
vaddr = kmap_atomic(page);
|
|
link = (struct link_free *)vaddr + off / sizeof(*link);
|
|
|
|
while ((off += class->size) < PAGE_SIZE) {
|
|
link->next = freeobj++ << OBJ_TAG_BITS;
|
|
link += class->size / sizeof(*link);
|
|
}
|
|
|
|
/*
|
|
* We now come to the last (full or partial) object on this
|
|
* page, which must point to the first object on the next
|
|
* page (if present)
|
|
*/
|
|
next_page = get_next_page(page);
|
|
if (next_page) {
|
|
link->next = freeobj++ << OBJ_TAG_BITS;
|
|
} else {
|
|
/*
|
|
* Reset OBJ_TAG_BITS bit to last link to tell
|
|
* whether it's allocated object or not.
|
|
*/
|
|
link->next = -1UL << OBJ_TAG_BITS;
|
|
}
|
|
kunmap_atomic(vaddr);
|
|
page = next_page;
|
|
off %= PAGE_SIZE;
|
|
}
|
|
|
|
set_freeobj(zspage, 0);
|
|
}
|
|
|
|
static void create_page_chain(struct size_class *class, struct zspage *zspage,
|
|
struct page *pages[])
|
|
{
|
|
int i;
|
|
struct page *page;
|
|
struct page *prev_page = NULL;
|
|
int nr_pages = class->pages_per_zspage;
|
|
|
|
/*
|
|
* Allocate individual pages and link them together as:
|
|
* 1. all pages are linked together using page->freelist
|
|
* 2. each sub-page point to zspage using page->private
|
|
*
|
|
* we set PG_private to identify the first page (i.e. no other sub-page
|
|
* has this flag set).
|
|
*/
|
|
for (i = 0; i < nr_pages; i++) {
|
|
page = pages[i];
|
|
set_page_private(page, (unsigned long)zspage);
|
|
page->freelist = NULL;
|
|
if (i == 0) {
|
|
zspage->first_page = page;
|
|
SetPagePrivate(page);
|
|
if (unlikely(class->objs_per_zspage == 1 &&
|
|
class->pages_per_zspage == 1))
|
|
SetPageHugeObject(page);
|
|
} else {
|
|
prev_page->freelist = page;
|
|
}
|
|
prev_page = page;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Allocate a zspage for the given size class
|
|
*/
|
|
static struct zspage *alloc_zspage(struct zs_pool *pool,
|
|
struct size_class *class,
|
|
gfp_t gfp)
|
|
{
|
|
int i;
|
|
struct page *pages[ZS_MAX_PAGES_PER_ZSPAGE];
|
|
struct zspage *zspage = cache_alloc_zspage(pool, gfp);
|
|
|
|
if (!zspage)
|
|
return NULL;
|
|
|
|
memset(zspage, 0, sizeof(struct zspage));
|
|
zspage->magic = ZSPAGE_MAGIC;
|
|
migrate_lock_init(zspage);
|
|
|
|
for (i = 0; i < class->pages_per_zspage; i++) {
|
|
struct page *page;
|
|
|
|
page = alloc_page(gfp);
|
|
if (!page) {
|
|
while (--i >= 0) {
|
|
dec_zone_page_state(pages[i], NR_ZSPAGES);
|
|
__free_page(pages[i]);
|
|
}
|
|
cache_free_zspage(pool, zspage);
|
|
return NULL;
|
|
}
|
|
|
|
inc_zone_page_state(page, NR_ZSPAGES);
|
|
pages[i] = page;
|
|
}
|
|
|
|
create_page_chain(class, zspage, pages);
|
|
init_zspage(class, zspage);
|
|
|
|
return zspage;
|
|
}
|
|
|
|
static struct zspage *find_get_zspage(struct size_class *class)
|
|
{
|
|
int i;
|
|
struct zspage *zspage;
|
|
|
|
for (i = ZS_ALMOST_FULL; i >= ZS_EMPTY; i--) {
|
|
zspage = list_first_entry_or_null(&class->fullness_list[i],
|
|
struct zspage, list);
|
|
if (zspage)
|
|
break;
|
|
}
|
|
|
|
return zspage;
|
|
}
|
|
|
|
#ifdef CONFIG_PGTABLE_MAPPING
|
|
static inline int __zs_cpu_up(struct mapping_area *area)
|
|
{
|
|
/*
|
|
* Make sure we don't leak memory if a cpu UP notification
|
|
* and zs_init() race and both call zs_cpu_up() on the same cpu
|
|
*/
|
|
if (area->vm)
|
|
return 0;
|
|
area->vm = alloc_vm_area(PAGE_SIZE * 2, NULL);
|
|
if (!area->vm)
|
|
return -ENOMEM;
|
|
return 0;
|
|
}
|
|
|
|
static inline void __zs_cpu_down(struct mapping_area *area)
|
|
{
|
|
if (area->vm)
|
|
free_vm_area(area->vm);
|
|
area->vm = NULL;
|
|
}
|
|
|
|
static inline void *__zs_map_object(struct mapping_area *area,
|
|
struct page *pages[2], int off, int size)
|
|
{
|
|
BUG_ON(map_vm_area(area->vm, PAGE_KERNEL, pages));
|
|
area->vm_addr = area->vm->addr;
|
|
return area->vm_addr + off;
|
|
}
|
|
|
|
static inline void __zs_unmap_object(struct mapping_area *area,
|
|
struct page *pages[2], int off, int size)
|
|
{
|
|
unsigned long addr = (unsigned long)area->vm_addr;
|
|
|
|
unmap_kernel_range(addr, PAGE_SIZE * 2);
|
|
}
|
|
|
|
#else /* CONFIG_PGTABLE_MAPPING */
|
|
|
|
static inline int __zs_cpu_up(struct mapping_area *area)
|
|
{
|
|
/*
|
|
* Make sure we don't leak memory if a cpu UP notification
|
|
* and zs_init() race and both call zs_cpu_up() on the same cpu
|
|
*/
|
|
if (area->vm_buf)
|
|
return 0;
|
|
area->vm_buf = kmalloc(ZS_MAX_ALLOC_SIZE, GFP_KERNEL);
|
|
if (!area->vm_buf)
|
|
return -ENOMEM;
|
|
return 0;
|
|
}
|
|
|
|
static inline void __zs_cpu_down(struct mapping_area *area)
|
|
{
|
|
kfree(area->vm_buf);
|
|
area->vm_buf = NULL;
|
|
}
|
|
|
|
static void *__zs_map_object(struct mapping_area *area,
|
|
struct page *pages[2], int off, int size)
|
|
{
|
|
int sizes[2];
|
|
void *addr;
|
|
char *buf = area->vm_buf;
|
|
|
|
/* disable page faults to match kmap_atomic() return conditions */
|
|
pagefault_disable();
|
|
|
|
/* no read fastpath */
|
|
if (area->vm_mm == ZS_MM_WO)
|
|
goto out;
|
|
|
|
sizes[0] = PAGE_SIZE - off;
|
|
sizes[1] = size - sizes[0];
|
|
|
|
/* copy object to per-cpu buffer */
|
|
addr = kmap_atomic(pages[0]);
|
|
memcpy(buf, addr + off, sizes[0]);
|
|
kunmap_atomic(addr);
|
|
addr = kmap_atomic(pages[1]);
|
|
memcpy(buf + sizes[0], addr, sizes[1]);
|
|
kunmap_atomic(addr);
|
|
out:
|
|
return area->vm_buf;
|
|
}
|
|
|
|
static void __zs_unmap_object(struct mapping_area *area,
|
|
struct page *pages[2], int off, int size)
|
|
{
|
|
int sizes[2];
|
|
void *addr;
|
|
char *buf;
|
|
|
|
/* no write fastpath */
|
|
if (area->vm_mm == ZS_MM_RO)
|
|
goto out;
|
|
|
|
buf = area->vm_buf;
|
|
buf = buf + ZS_HANDLE_SIZE;
|
|
size -= ZS_HANDLE_SIZE;
|
|
off += ZS_HANDLE_SIZE;
|
|
|
|
sizes[0] = PAGE_SIZE - off;
|
|
sizes[1] = size - sizes[0];
|
|
|
|
/* copy per-cpu buffer to object */
|
|
addr = kmap_atomic(pages[0]);
|
|
memcpy(addr + off, buf, sizes[0]);
|
|
kunmap_atomic(addr);
|
|
addr = kmap_atomic(pages[1]);
|
|
memcpy(addr, buf + sizes[0], sizes[1]);
|
|
kunmap_atomic(addr);
|
|
|
|
out:
|
|
/* enable page faults to match kunmap_atomic() return conditions */
|
|
pagefault_enable();
|
|
}
|
|
|
|
#endif /* CONFIG_PGTABLE_MAPPING */
|
|
|
|
static int zs_cpu_prepare(unsigned int cpu)
|
|
{
|
|
struct mapping_area *area;
|
|
|
|
area = &per_cpu(zs_map_area, cpu);
|
|
return __zs_cpu_up(area);
|
|
}
|
|
|
|
static int zs_cpu_dead(unsigned int cpu)
|
|
{
|
|
struct mapping_area *area;
|
|
|
|
area = &per_cpu(zs_map_area, cpu);
|
|
__zs_cpu_down(area);
|
|
return 0;
|
|
}
|
|
|
|
static bool can_merge(struct size_class *prev, int pages_per_zspage,
|
|
int objs_per_zspage)
|
|
{
|
|
if (prev->pages_per_zspage == pages_per_zspage &&
|
|
prev->objs_per_zspage == objs_per_zspage)
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
static bool zspage_full(struct size_class *class, struct zspage *zspage)
|
|
{
|
|
return get_zspage_inuse(zspage) == class->objs_per_zspage;
|
|
}
|
|
|
|
unsigned long zs_get_total_pages(struct zs_pool *pool)
|
|
{
|
|
return atomic_long_read(&pool->pages_allocated);
|
|
}
|
|
EXPORT_SYMBOL_GPL(zs_get_total_pages);
|
|
|
|
/**
|
|
* zs_map_object - get address of allocated object from handle.
|
|
* @pool: pool from which the object was allocated
|
|
* @handle: handle returned from zs_malloc
|
|
* @mm: maping mode to use
|
|
*
|
|
* Before using an object allocated from zs_malloc, it must be mapped using
|
|
* this function. When done with the object, it must be unmapped using
|
|
* zs_unmap_object.
|
|
*
|
|
* Only one object can be mapped per cpu at a time. There is no protection
|
|
* against nested mappings.
|
|
*
|
|
* This function returns with preemption and page faults disabled.
|
|
*/
|
|
void *zs_map_object(struct zs_pool *pool, unsigned long handle,
|
|
enum zs_mapmode mm)
|
|
{
|
|
struct zspage *zspage;
|
|
struct page *page;
|
|
unsigned long obj, off;
|
|
unsigned int obj_idx;
|
|
|
|
unsigned int class_idx;
|
|
enum fullness_group fg;
|
|
struct size_class *class;
|
|
struct mapping_area *area;
|
|
struct page *pages[2];
|
|
void *ret;
|
|
|
|
/*
|
|
* Because we use per-cpu mapping areas shared among the
|
|
* pools/users, we can't allow mapping in interrupt context
|
|
* because it can corrupt another users mappings.
|
|
*/
|
|
BUG_ON(in_interrupt());
|
|
|
|
/* From now on, migration cannot move the object */
|
|
pin_tag(handle);
|
|
|
|
obj = handle_to_obj(handle);
|
|
obj_to_location(obj, &page, &obj_idx);
|
|
zspage = get_zspage(page);
|
|
|
|
/* migration cannot move any subpage in this zspage */
|
|
migrate_read_lock(zspage);
|
|
|
|
get_zspage_mapping(zspage, &class_idx, &fg);
|
|
class = pool->size_class[class_idx];
|
|
off = (class->size * obj_idx) & ~PAGE_MASK;
|
|
|
|
area = &get_cpu_var(zs_map_area);
|
|
area->vm_mm = mm;
|
|
if (off + class->size <= PAGE_SIZE) {
|
|
/* this object is contained entirely within a page */
|
|
area->vm_addr = kmap_atomic(page);
|
|
ret = area->vm_addr + off;
|
|
goto out;
|
|
}
|
|
|
|
/* this object spans two pages */
|
|
pages[0] = page;
|
|
pages[1] = get_next_page(page);
|
|
BUG_ON(!pages[1]);
|
|
|
|
ret = __zs_map_object(area, pages, off, class->size);
|
|
out:
|
|
if (likely(!PageHugeObject(page)))
|
|
ret += ZS_HANDLE_SIZE;
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(zs_map_object);
|
|
|
|
void zs_unmap_object(struct zs_pool *pool, unsigned long handle)
|
|
{
|
|
struct zspage *zspage;
|
|
struct page *page;
|
|
unsigned long obj, off;
|
|
unsigned int obj_idx;
|
|
|
|
unsigned int class_idx;
|
|
enum fullness_group fg;
|
|
struct size_class *class;
|
|
struct mapping_area *area;
|
|
|
|
obj = handle_to_obj(handle);
|
|
obj_to_location(obj, &page, &obj_idx);
|
|
zspage = get_zspage(page);
|
|
get_zspage_mapping(zspage, &class_idx, &fg);
|
|
class = pool->size_class[class_idx];
|
|
off = (class->size * obj_idx) & ~PAGE_MASK;
|
|
|
|
area = this_cpu_ptr(&zs_map_area);
|
|
if (off + class->size <= PAGE_SIZE)
|
|
kunmap_atomic(area->vm_addr);
|
|
else {
|
|
struct page *pages[2];
|
|
|
|
pages[0] = page;
|
|
pages[1] = get_next_page(page);
|
|
BUG_ON(!pages[1]);
|
|
|
|
__zs_unmap_object(area, pages, off, class->size);
|
|
}
|
|
put_cpu_var(zs_map_area);
|
|
|
|
migrate_read_unlock(zspage);
|
|
unpin_tag(handle);
|
|
}
|
|
EXPORT_SYMBOL_GPL(zs_unmap_object);
|
|
|
|
/**
|
|
* zs_huge_class_size() - Returns the size (in bytes) of the first huge
|
|
* zsmalloc &size_class.
|
|
* @pool: zsmalloc pool to use
|
|
*
|
|
* The function returns the size of the first huge class - any object of equal
|
|
* or bigger size will be stored in zspage consisting of a single physical
|
|
* page.
|
|
*
|
|
* Context: Any context.
|
|
*
|
|
* Return: the size (in bytes) of the first huge zsmalloc &size_class.
|
|
*/
|
|
size_t zs_huge_class_size(struct zs_pool *pool)
|
|
{
|
|
return huge_class_size;
|
|
}
|
|
EXPORT_SYMBOL_GPL(zs_huge_class_size);
|
|
|
|
static unsigned long obj_malloc(struct size_class *class,
|
|
struct zspage *zspage, unsigned long handle)
|
|
{
|
|
int i, nr_page, offset;
|
|
unsigned long obj;
|
|
struct link_free *link;
|
|
|
|
struct page *m_page;
|
|
unsigned long m_offset;
|
|
void *vaddr;
|
|
|
|
handle |= OBJ_ALLOCATED_TAG;
|
|
obj = get_freeobj(zspage);
|
|
|
|
offset = obj * class->size;
|
|
nr_page = offset >> PAGE_SHIFT;
|
|
m_offset = offset & ~PAGE_MASK;
|
|
m_page = get_first_page(zspage);
|
|
|
|
for (i = 0; i < nr_page; i++)
|
|
m_page = get_next_page(m_page);
|
|
|
|
vaddr = kmap_atomic(m_page);
|
|
link = (struct link_free *)vaddr + m_offset / sizeof(*link);
|
|
set_freeobj(zspage, link->next >> OBJ_TAG_BITS);
|
|
if (likely(!PageHugeObject(m_page)))
|
|
/* record handle in the header of allocated chunk */
|
|
link->handle = handle;
|
|
else
|
|
/* record handle to page->index */
|
|
zspage->first_page->index = handle;
|
|
|
|
kunmap_atomic(vaddr);
|
|
mod_zspage_inuse(zspage, 1);
|
|
zs_stat_inc(class, OBJ_USED, 1);
|
|
|
|
obj = location_to_obj(m_page, obj);
|
|
|
|
return obj;
|
|
}
|
|
|
|
|
|
/**
|
|
* zs_malloc - Allocate block of given size from pool.
|
|
* @pool: pool to allocate from
|
|
* @size: size of block to allocate
|
|
* @gfp: gfp flags when allocating object
|
|
*
|
|
* On success, handle to the allocated object is returned,
|
|
* otherwise 0.
|
|
* Allocation requests with size > ZS_MAX_ALLOC_SIZE will fail.
|
|
*/
|
|
unsigned long zs_malloc(struct zs_pool *pool, size_t size, gfp_t gfp)
|
|
{
|
|
unsigned long handle, obj;
|
|
struct size_class *class;
|
|
enum fullness_group newfg;
|
|
struct zspage *zspage;
|
|
|
|
if (unlikely(!size || size > ZS_MAX_ALLOC_SIZE))
|
|
return 0;
|
|
|
|
handle = cache_alloc_handle(pool, gfp);
|
|
if (!handle)
|
|
return 0;
|
|
|
|
/* extra space in chunk to keep the handle */
|
|
size += ZS_HANDLE_SIZE;
|
|
class = pool->size_class[get_size_class_index(size)];
|
|
|
|
spin_lock(&class->lock);
|
|
zspage = find_get_zspage(class);
|
|
if (likely(zspage)) {
|
|
obj = obj_malloc(class, zspage, handle);
|
|
/* Now move the zspage to another fullness group, if required */
|
|
fix_fullness_group(class, zspage);
|
|
record_obj(handle, obj);
|
|
spin_unlock(&class->lock);
|
|
|
|
return handle;
|
|
}
|
|
|
|
spin_unlock(&class->lock);
|
|
|
|
zspage = alloc_zspage(pool, class, gfp);
|
|
if (!zspage) {
|
|
cache_free_handle(pool, handle);
|
|
return 0;
|
|
}
|
|
|
|
spin_lock(&class->lock);
|
|
obj = obj_malloc(class, zspage, handle);
|
|
newfg = get_fullness_group(class, zspage);
|
|
insert_zspage(class, zspage, newfg);
|
|
set_zspage_mapping(zspage, class->index, newfg);
|
|
record_obj(handle, obj);
|
|
atomic_long_add(class->pages_per_zspage,
|
|
&pool->pages_allocated);
|
|
zs_stat_inc(class, OBJ_ALLOCATED, class->objs_per_zspage);
|
|
|
|
/* We completely set up zspage so mark them as movable */
|
|
SetZsPageMovable(pool, zspage);
|
|
spin_unlock(&class->lock);
|
|
|
|
return handle;
|
|
}
|
|
EXPORT_SYMBOL_GPL(zs_malloc);
|
|
|
|
static void obj_free(struct size_class *class, unsigned long obj)
|
|
{
|
|
struct link_free *link;
|
|
struct zspage *zspage;
|
|
struct page *f_page;
|
|
unsigned long f_offset;
|
|
unsigned int f_objidx;
|
|
void *vaddr;
|
|
|
|
obj &= ~OBJ_ALLOCATED_TAG;
|
|
obj_to_location(obj, &f_page, &f_objidx);
|
|
f_offset = (class->size * f_objidx) & ~PAGE_MASK;
|
|
zspage = get_zspage(f_page);
|
|
|
|
vaddr = kmap_atomic(f_page);
|
|
|
|
/* Insert this object in containing zspage's freelist */
|
|
link = (struct link_free *)(vaddr + f_offset);
|
|
link->next = get_freeobj(zspage) << OBJ_TAG_BITS;
|
|
kunmap_atomic(vaddr);
|
|
set_freeobj(zspage, f_objidx);
|
|
mod_zspage_inuse(zspage, -1);
|
|
zs_stat_dec(class, OBJ_USED, 1);
|
|
}
|
|
|
|
void zs_free(struct zs_pool *pool, unsigned long handle)
|
|
{
|
|
struct zspage *zspage;
|
|
struct page *f_page;
|
|
unsigned long obj;
|
|
unsigned int f_objidx;
|
|
int class_idx;
|
|
struct size_class *class;
|
|
enum fullness_group fullness;
|
|
bool isolated;
|
|
|
|
if (unlikely(!handle))
|
|
return;
|
|
|
|
pin_tag(handle);
|
|
obj = handle_to_obj(handle);
|
|
obj_to_location(obj, &f_page, &f_objidx);
|
|
zspage = get_zspage(f_page);
|
|
|
|
migrate_read_lock(zspage);
|
|
|
|
get_zspage_mapping(zspage, &class_idx, &fullness);
|
|
class = pool->size_class[class_idx];
|
|
|
|
spin_lock(&class->lock);
|
|
obj_free(class, obj);
|
|
fullness = fix_fullness_group(class, zspage);
|
|
if (fullness != ZS_EMPTY) {
|
|
migrate_read_unlock(zspage);
|
|
goto out;
|
|
}
|
|
|
|
isolated = is_zspage_isolated(zspage);
|
|
migrate_read_unlock(zspage);
|
|
/* If zspage is isolated, zs_page_putback will free the zspage */
|
|
if (likely(!isolated))
|
|
free_zspage(pool, class, zspage);
|
|
out:
|
|
|
|
spin_unlock(&class->lock);
|
|
unpin_tag(handle);
|
|
cache_free_handle(pool, handle);
|
|
}
|
|
EXPORT_SYMBOL_GPL(zs_free);
|
|
|
|
static void zs_object_copy(struct size_class *class, unsigned long dst,
|
|
unsigned long src)
|
|
{
|
|
struct page *s_page, *d_page;
|
|
unsigned int s_objidx, d_objidx;
|
|
unsigned long s_off, d_off;
|
|
void *s_addr, *d_addr;
|
|
int s_size, d_size, size;
|
|
int written = 0;
|
|
|
|
s_size = d_size = class->size;
|
|
|
|
obj_to_location(src, &s_page, &s_objidx);
|
|
obj_to_location(dst, &d_page, &d_objidx);
|
|
|
|
s_off = (class->size * s_objidx) & ~PAGE_MASK;
|
|
d_off = (class->size * d_objidx) & ~PAGE_MASK;
|
|
|
|
if (s_off + class->size > PAGE_SIZE)
|
|
s_size = PAGE_SIZE - s_off;
|
|
|
|
if (d_off + class->size > PAGE_SIZE)
|
|
d_size = PAGE_SIZE - d_off;
|
|
|
|
s_addr = kmap_atomic(s_page);
|
|
d_addr = kmap_atomic(d_page);
|
|
|
|
while (1) {
|
|
size = min(s_size, d_size);
|
|
memcpy(d_addr + d_off, s_addr + s_off, size);
|
|
written += size;
|
|
|
|
if (written == class->size)
|
|
break;
|
|
|
|
s_off += size;
|
|
s_size -= size;
|
|
d_off += size;
|
|
d_size -= size;
|
|
|
|
if (s_off >= PAGE_SIZE) {
|
|
kunmap_atomic(d_addr);
|
|
kunmap_atomic(s_addr);
|
|
s_page = get_next_page(s_page);
|
|
s_addr = kmap_atomic(s_page);
|
|
d_addr = kmap_atomic(d_page);
|
|
s_size = class->size - written;
|
|
s_off = 0;
|
|
}
|
|
|
|
if (d_off >= PAGE_SIZE) {
|
|
kunmap_atomic(d_addr);
|
|
d_page = get_next_page(d_page);
|
|
d_addr = kmap_atomic(d_page);
|
|
d_size = class->size - written;
|
|
d_off = 0;
|
|
}
|
|
}
|
|
|
|
kunmap_atomic(d_addr);
|
|
kunmap_atomic(s_addr);
|
|
}
|
|
|
|
/*
|
|
* Find alloced object in zspage from index object and
|
|
* return handle.
|
|
*/
|
|
static unsigned long find_alloced_obj(struct size_class *class,
|
|
struct page *page, int *obj_idx)
|
|
{
|
|
unsigned long head;
|
|
int offset = 0;
|
|
int index = *obj_idx;
|
|
unsigned long handle = 0;
|
|
void *addr = kmap_atomic(page);
|
|
|
|
offset = get_first_obj_offset(page);
|
|
offset += class->size * index;
|
|
|
|
while (offset < PAGE_SIZE) {
|
|
head = obj_to_head(page, addr + offset);
|
|
if (head & OBJ_ALLOCATED_TAG) {
|
|
handle = head & ~OBJ_ALLOCATED_TAG;
|
|
if (trypin_tag(handle))
|
|
break;
|
|
handle = 0;
|
|
}
|
|
|
|
offset += class->size;
|
|
index++;
|
|
}
|
|
|
|
kunmap_atomic(addr);
|
|
|
|
*obj_idx = index;
|
|
|
|
return handle;
|
|
}
|
|
|
|
struct zs_compact_control {
|
|
/* Source spage for migration which could be a subpage of zspage */
|
|
struct page *s_page;
|
|
/* Destination page for migration which should be a first page
|
|
* of zspage. */
|
|
struct page *d_page;
|
|
/* Starting object index within @s_page which used for live object
|
|
* in the subpage. */
|
|
int obj_idx;
|
|
};
|
|
|
|
static int migrate_zspage(struct zs_pool *pool, struct size_class *class,
|
|
struct zs_compact_control *cc)
|
|
{
|
|
unsigned long used_obj, free_obj;
|
|
unsigned long handle;
|
|
struct page *s_page = cc->s_page;
|
|
struct page *d_page = cc->d_page;
|
|
int obj_idx = cc->obj_idx;
|
|
int ret = 0;
|
|
|
|
while (1) {
|
|
handle = find_alloced_obj(class, s_page, &obj_idx);
|
|
if (!handle) {
|
|
s_page = get_next_page(s_page);
|
|
if (!s_page)
|
|
break;
|
|
obj_idx = 0;
|
|
continue;
|
|
}
|
|
|
|
/* Stop if there is no more space */
|
|
if (zspage_full(class, get_zspage(d_page))) {
|
|
unpin_tag(handle);
|
|
ret = -ENOMEM;
|
|
break;
|
|
}
|
|
|
|
used_obj = handle_to_obj(handle);
|
|
free_obj = obj_malloc(class, get_zspage(d_page), handle);
|
|
zs_object_copy(class, free_obj, used_obj);
|
|
obj_idx++;
|
|
/*
|
|
* record_obj updates handle's value to free_obj and it will
|
|
* invalidate lock bit(ie, HANDLE_PIN_BIT) of handle, which
|
|
* breaks synchronization using pin_tag(e,g, zs_free) so
|
|
* let's keep the lock bit.
|
|
*/
|
|
free_obj |= BIT(HANDLE_PIN_BIT);
|
|
record_obj(handle, free_obj);
|
|
unpin_tag(handle);
|
|
obj_free(class, used_obj);
|
|
}
|
|
|
|
/* Remember last position in this iteration */
|
|
cc->s_page = s_page;
|
|
cc->obj_idx = obj_idx;
|
|
|
|
return ret;
|
|
}
|
|
|
|
static struct zspage *isolate_zspage(struct size_class *class, bool source)
|
|
{
|
|
int i;
|
|
struct zspage *zspage;
|
|
enum fullness_group fg[2] = {ZS_ALMOST_EMPTY, ZS_ALMOST_FULL};
|
|
|
|
if (!source) {
|
|
fg[0] = ZS_ALMOST_FULL;
|
|
fg[1] = ZS_ALMOST_EMPTY;
|
|
}
|
|
|
|
for (i = 0; i < 2; i++) {
|
|
zspage = list_first_entry_or_null(&class->fullness_list[fg[i]],
|
|
struct zspage, list);
|
|
if (zspage) {
|
|
VM_BUG_ON(is_zspage_isolated(zspage));
|
|
remove_zspage(class, zspage, fg[i]);
|
|
return zspage;
|
|
}
|
|
}
|
|
|
|
return zspage;
|
|
}
|
|
|
|
/*
|
|
* putback_zspage - add @zspage into right class's fullness list
|
|
* @class: destination class
|
|
* @zspage: target page
|
|
*
|
|
* Return @zspage's fullness_group
|
|
*/
|
|
static enum fullness_group putback_zspage(struct size_class *class,
|
|
struct zspage *zspage)
|
|
{
|
|
enum fullness_group fullness;
|
|
|
|
VM_BUG_ON(is_zspage_isolated(zspage));
|
|
|
|
fullness = get_fullness_group(class, zspage);
|
|
insert_zspage(class, zspage, fullness);
|
|
set_zspage_mapping(zspage, class->index, fullness);
|
|
|
|
return fullness;
|
|
}
|
|
|
|
#ifdef CONFIG_COMPACTION
|
|
/*
|
|
* To prevent zspage destroy during migration, zspage freeing should
|
|
* hold locks of all pages in the zspage.
|
|
*/
|
|
static void lock_zspage(struct zspage *zspage)
|
|
{
|
|
struct page *page = get_first_page(zspage);
|
|
|
|
do {
|
|
lock_page(page);
|
|
} while ((page = get_next_page(page)) != NULL);
|
|
}
|
|
|
|
static int zs_init_fs_context(struct fs_context *fc)
|
|
{
|
|
return init_pseudo(fc, ZSMALLOC_MAGIC) ? 0 : -ENOMEM;
|
|
}
|
|
|
|
static struct file_system_type zsmalloc_fs = {
|
|
.name = "zsmalloc",
|
|
.init_fs_context = zs_init_fs_context,
|
|
.kill_sb = kill_anon_super,
|
|
};
|
|
|
|
static int zsmalloc_mount(void)
|
|
{
|
|
int ret = 0;
|
|
|
|
zsmalloc_mnt = kern_mount(&zsmalloc_fs);
|
|
if (IS_ERR(zsmalloc_mnt))
|
|
ret = PTR_ERR(zsmalloc_mnt);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void zsmalloc_unmount(void)
|
|
{
|
|
kern_unmount(zsmalloc_mnt);
|
|
}
|
|
|
|
static void migrate_lock_init(struct zspage *zspage)
|
|
{
|
|
rwlock_init(&zspage->lock);
|
|
}
|
|
|
|
static void migrate_read_lock(struct zspage *zspage)
|
|
{
|
|
read_lock(&zspage->lock);
|
|
}
|
|
|
|
static void migrate_read_unlock(struct zspage *zspage)
|
|
{
|
|
read_unlock(&zspage->lock);
|
|
}
|
|
|
|
static void migrate_write_lock(struct zspage *zspage)
|
|
{
|
|
write_lock(&zspage->lock);
|
|
}
|
|
|
|
static void migrate_write_unlock(struct zspage *zspage)
|
|
{
|
|
write_unlock(&zspage->lock);
|
|
}
|
|
|
|
/* Number of isolated subpage for *page migration* in this zspage */
|
|
static void inc_zspage_isolation(struct zspage *zspage)
|
|
{
|
|
zspage->isolated++;
|
|
}
|
|
|
|
static void dec_zspage_isolation(struct zspage *zspage)
|
|
{
|
|
zspage->isolated--;
|
|
}
|
|
|
|
static void putback_zspage_deferred(struct zs_pool *pool,
|
|
struct size_class *class,
|
|
struct zspage *zspage)
|
|
{
|
|
enum fullness_group fg;
|
|
|
|
fg = putback_zspage(class, zspage);
|
|
if (fg == ZS_EMPTY)
|
|
schedule_work(&pool->free_work);
|
|
|
|
}
|
|
|
|
static inline void zs_pool_dec_isolated(struct zs_pool *pool)
|
|
{
|
|
VM_BUG_ON(atomic_long_read(&pool->isolated_pages) <= 0);
|
|
atomic_long_dec(&pool->isolated_pages);
|
|
/*
|
|
* There's no possibility of racing, since wait_for_isolated_drain()
|
|
* checks the isolated count under &class->lock after enqueuing
|
|
* on migration_wait.
|
|
*/
|
|
if (atomic_long_read(&pool->isolated_pages) == 0 && pool->destroying)
|
|
wake_up_all(&pool->migration_wait);
|
|
}
|
|
|
|
static void replace_sub_page(struct size_class *class, struct zspage *zspage,
|
|
struct page *newpage, struct page *oldpage)
|
|
{
|
|
struct page *page;
|
|
struct page *pages[ZS_MAX_PAGES_PER_ZSPAGE] = {NULL, };
|
|
int idx = 0;
|
|
|
|
page = get_first_page(zspage);
|
|
do {
|
|
if (page == oldpage)
|
|
pages[idx] = newpage;
|
|
else
|
|
pages[idx] = page;
|
|
idx++;
|
|
} while ((page = get_next_page(page)) != NULL);
|
|
|
|
create_page_chain(class, zspage, pages);
|
|
set_first_obj_offset(newpage, get_first_obj_offset(oldpage));
|
|
if (unlikely(PageHugeObject(oldpage)))
|
|
newpage->index = oldpage->index;
|
|
__SetPageMovable(newpage, page_mapping(oldpage));
|
|
}
|
|
|
|
static bool zs_page_isolate(struct page *page, isolate_mode_t mode)
|
|
{
|
|
struct zs_pool *pool;
|
|
struct size_class *class;
|
|
int class_idx;
|
|
enum fullness_group fullness;
|
|
struct zspage *zspage;
|
|
struct address_space *mapping;
|
|
|
|
/*
|
|
* Page is locked so zspage couldn't be destroyed. For detail, look at
|
|
* lock_zspage in free_zspage.
|
|
*/
|
|
VM_BUG_ON_PAGE(!PageMovable(page), page);
|
|
VM_BUG_ON_PAGE(PageIsolated(page), page);
|
|
|
|
zspage = get_zspage(page);
|
|
|
|
/*
|
|
* Without class lock, fullness could be stale while class_idx is okay
|
|
* because class_idx is constant unless page is freed so we should get
|
|
* fullness again under class lock.
|
|
*/
|
|
get_zspage_mapping(zspage, &class_idx, &fullness);
|
|
mapping = page_mapping(page);
|
|
pool = mapping->private_data;
|
|
class = pool->size_class[class_idx];
|
|
|
|
spin_lock(&class->lock);
|
|
if (get_zspage_inuse(zspage) == 0) {
|
|
spin_unlock(&class->lock);
|
|
return false;
|
|
}
|
|
|
|
/* zspage is isolated for object migration */
|
|
if (list_empty(&zspage->list) && !is_zspage_isolated(zspage)) {
|
|
spin_unlock(&class->lock);
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* If this is first time isolation for the zspage, isolate zspage from
|
|
* size_class to prevent further object allocation from the zspage.
|
|
*/
|
|
if (!list_empty(&zspage->list) && !is_zspage_isolated(zspage)) {
|
|
get_zspage_mapping(zspage, &class_idx, &fullness);
|
|
atomic_long_inc(&pool->isolated_pages);
|
|
remove_zspage(class, zspage, fullness);
|
|
}
|
|
|
|
inc_zspage_isolation(zspage);
|
|
spin_unlock(&class->lock);
|
|
|
|
return true;
|
|
}
|
|
|
|
static int zs_page_migrate(struct address_space *mapping, struct page *newpage,
|
|
struct page *page, enum migrate_mode mode)
|
|
{
|
|
struct zs_pool *pool;
|
|
struct size_class *class;
|
|
int class_idx;
|
|
enum fullness_group fullness;
|
|
struct zspage *zspage;
|
|
struct page *dummy;
|
|
void *s_addr, *d_addr, *addr;
|
|
int offset, pos;
|
|
unsigned long handle, head;
|
|
unsigned long old_obj, new_obj;
|
|
unsigned int obj_idx;
|
|
int ret = -EAGAIN;
|
|
|
|
/*
|
|
* We cannot support the _NO_COPY case here, because copy needs to
|
|
* happen under the zs lock, which does not work with
|
|
* MIGRATE_SYNC_NO_COPY workflow.
|
|
*/
|
|
if (mode == MIGRATE_SYNC_NO_COPY)
|
|
return -EINVAL;
|
|
|
|
VM_BUG_ON_PAGE(!PageMovable(page), page);
|
|
VM_BUG_ON_PAGE(!PageIsolated(page), page);
|
|
|
|
zspage = get_zspage(page);
|
|
|
|
/* Concurrent compactor cannot migrate any subpage in zspage */
|
|
migrate_write_lock(zspage);
|
|
get_zspage_mapping(zspage, &class_idx, &fullness);
|
|
pool = mapping->private_data;
|
|
class = pool->size_class[class_idx];
|
|
offset = get_first_obj_offset(page);
|
|
|
|
spin_lock(&class->lock);
|
|
if (!get_zspage_inuse(zspage)) {
|
|
/*
|
|
* Set "offset" to end of the page so that every loops
|
|
* skips unnecessary object scanning.
|
|
*/
|
|
offset = PAGE_SIZE;
|
|
}
|
|
|
|
pos = offset;
|
|
s_addr = kmap_atomic(page);
|
|
while (pos < PAGE_SIZE) {
|
|
head = obj_to_head(page, s_addr + pos);
|
|
if (head & OBJ_ALLOCATED_TAG) {
|
|
handle = head & ~OBJ_ALLOCATED_TAG;
|
|
if (!trypin_tag(handle))
|
|
goto unpin_objects;
|
|
}
|
|
pos += class->size;
|
|
}
|
|
|
|
/*
|
|
* Here, any user cannot access all objects in the zspage so let's move.
|
|
*/
|
|
d_addr = kmap_atomic(newpage);
|
|
memcpy(d_addr, s_addr, PAGE_SIZE);
|
|
kunmap_atomic(d_addr);
|
|
|
|
for (addr = s_addr + offset; addr < s_addr + pos;
|
|
addr += class->size) {
|
|
head = obj_to_head(page, addr);
|
|
if (head & OBJ_ALLOCATED_TAG) {
|
|
handle = head & ~OBJ_ALLOCATED_TAG;
|
|
if (!testpin_tag(handle))
|
|
BUG();
|
|
|
|
old_obj = handle_to_obj(handle);
|
|
obj_to_location(old_obj, &dummy, &obj_idx);
|
|
new_obj = (unsigned long)location_to_obj(newpage,
|
|
obj_idx);
|
|
new_obj |= BIT(HANDLE_PIN_BIT);
|
|
record_obj(handle, new_obj);
|
|
}
|
|
}
|
|
|
|
replace_sub_page(class, zspage, newpage, page);
|
|
get_page(newpage);
|
|
|
|
dec_zspage_isolation(zspage);
|
|
|
|
/*
|
|
* Page migration is done so let's putback isolated zspage to
|
|
* the list if @page is final isolated subpage in the zspage.
|
|
*/
|
|
if (!is_zspage_isolated(zspage)) {
|
|
/*
|
|
* We cannot race with zs_destroy_pool() here because we wait
|
|
* for isolation to hit zero before we start destroying.
|
|
* Also, we ensure that everyone can see pool->destroying before
|
|
* we start waiting.
|
|
*/
|
|
putback_zspage_deferred(pool, class, zspage);
|
|
zs_pool_dec_isolated(pool);
|
|
}
|
|
|
|
reset_page(page);
|
|
put_page(page);
|
|
page = newpage;
|
|
|
|
ret = MIGRATEPAGE_SUCCESS;
|
|
unpin_objects:
|
|
for (addr = s_addr + offset; addr < s_addr + pos;
|
|
addr += class->size) {
|
|
head = obj_to_head(page, addr);
|
|
if (head & OBJ_ALLOCATED_TAG) {
|
|
handle = head & ~OBJ_ALLOCATED_TAG;
|
|
if (!testpin_tag(handle))
|
|
BUG();
|
|
unpin_tag(handle);
|
|
}
|
|
}
|
|
kunmap_atomic(s_addr);
|
|
spin_unlock(&class->lock);
|
|
migrate_write_unlock(zspage);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void zs_page_putback(struct page *page)
|
|
{
|
|
struct zs_pool *pool;
|
|
struct size_class *class;
|
|
int class_idx;
|
|
enum fullness_group fg;
|
|
struct address_space *mapping;
|
|
struct zspage *zspage;
|
|
|
|
VM_BUG_ON_PAGE(!PageMovable(page), page);
|
|
VM_BUG_ON_PAGE(!PageIsolated(page), page);
|
|
|
|
zspage = get_zspage(page);
|
|
get_zspage_mapping(zspage, &class_idx, &fg);
|
|
mapping = page_mapping(page);
|
|
pool = mapping->private_data;
|
|
class = pool->size_class[class_idx];
|
|
|
|
spin_lock(&class->lock);
|
|
dec_zspage_isolation(zspage);
|
|
if (!is_zspage_isolated(zspage)) {
|
|
/*
|
|
* Due to page_lock, we cannot free zspage immediately
|
|
* so let's defer.
|
|
*/
|
|
putback_zspage_deferred(pool, class, zspage);
|
|
zs_pool_dec_isolated(pool);
|
|
}
|
|
spin_unlock(&class->lock);
|
|
}
|
|
|
|
static const struct address_space_operations zsmalloc_aops = {
|
|
.isolate_page = zs_page_isolate,
|
|
.migratepage = zs_page_migrate,
|
|
.putback_page = zs_page_putback,
|
|
};
|
|
|
|
static int zs_register_migration(struct zs_pool *pool)
|
|
{
|
|
pool->inode = alloc_anon_inode(zsmalloc_mnt->mnt_sb);
|
|
if (IS_ERR(pool->inode)) {
|
|
pool->inode = NULL;
|
|
return 1;
|
|
}
|
|
|
|
pool->inode->i_mapping->private_data = pool;
|
|
pool->inode->i_mapping->a_ops = &zsmalloc_aops;
|
|
return 0;
|
|
}
|
|
|
|
static bool pool_isolated_are_drained(struct zs_pool *pool)
|
|
{
|
|
return atomic_long_read(&pool->isolated_pages) == 0;
|
|
}
|
|
|
|
/* Function for resolving migration */
|
|
static void wait_for_isolated_drain(struct zs_pool *pool)
|
|
{
|
|
|
|
/*
|
|
* We're in the process of destroying the pool, so there are no
|
|
* active allocations. zs_page_isolate() fails for completely free
|
|
* zspages, so we need only wait for the zs_pool's isolated
|
|
* count to hit zero.
|
|
*/
|
|
wait_event(pool->migration_wait,
|
|
pool_isolated_are_drained(pool));
|
|
}
|
|
|
|
static void zs_unregister_migration(struct zs_pool *pool)
|
|
{
|
|
pool->destroying = true;
|
|
/*
|
|
* We need a memory barrier here to ensure global visibility of
|
|
* pool->destroying. Thus pool->isolated pages will either be 0 in which
|
|
* case we don't care, or it will be > 0 and pool->destroying will
|
|
* ensure that we wake up once isolation hits 0.
|
|
*/
|
|
smp_mb();
|
|
wait_for_isolated_drain(pool); /* This can block */
|
|
flush_work(&pool->free_work);
|
|
iput(pool->inode);
|
|
}
|
|
|
|
/*
|
|
* Caller should hold page_lock of all pages in the zspage
|
|
* In here, we cannot use zspage meta data.
|
|
*/
|
|
static void async_free_zspage(struct work_struct *work)
|
|
{
|
|
int i;
|
|
struct size_class *class;
|
|
unsigned int class_idx;
|
|
enum fullness_group fullness;
|
|
struct zspage *zspage, *tmp;
|
|
LIST_HEAD(free_pages);
|
|
struct zs_pool *pool = container_of(work, struct zs_pool,
|
|
free_work);
|
|
|
|
for (i = 0; i < ZS_SIZE_CLASSES; i++) {
|
|
class = pool->size_class[i];
|
|
if (class->index != i)
|
|
continue;
|
|
|
|
spin_lock(&class->lock);
|
|
list_splice_init(&class->fullness_list[ZS_EMPTY], &free_pages);
|
|
spin_unlock(&class->lock);
|
|
}
|
|
|
|
|
|
list_for_each_entry_safe(zspage, tmp, &free_pages, list) {
|
|
list_del(&zspage->list);
|
|
lock_zspage(zspage);
|
|
|
|
get_zspage_mapping(zspage, &class_idx, &fullness);
|
|
VM_BUG_ON(fullness != ZS_EMPTY);
|
|
class = pool->size_class[class_idx];
|
|
spin_lock(&class->lock);
|
|
__free_zspage(pool, pool->size_class[class_idx], zspage);
|
|
spin_unlock(&class->lock);
|
|
}
|
|
};
|
|
|
|
static void kick_deferred_free(struct zs_pool *pool)
|
|
{
|
|
schedule_work(&pool->free_work);
|
|
}
|
|
|
|
static void init_deferred_free(struct zs_pool *pool)
|
|
{
|
|
INIT_WORK(&pool->free_work, async_free_zspage);
|
|
}
|
|
|
|
static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage)
|
|
{
|
|
struct page *page = get_first_page(zspage);
|
|
|
|
do {
|
|
WARN_ON(!trylock_page(page));
|
|
__SetPageMovable(page, pool->inode->i_mapping);
|
|
unlock_page(page);
|
|
} while ((page = get_next_page(page)) != NULL);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
*
|
|
* Based on the number of unused allocated objects calculate
|
|
* and return the number of pages that we can free.
|
|
*/
|
|
static unsigned long zs_can_compact(struct size_class *class)
|
|
{
|
|
unsigned long obj_wasted;
|
|
unsigned long obj_allocated = zs_stat_get(class, OBJ_ALLOCATED);
|
|
unsigned long obj_used = zs_stat_get(class, OBJ_USED);
|
|
|
|
if (obj_allocated <= obj_used)
|
|
return 0;
|
|
|
|
obj_wasted = obj_allocated - obj_used;
|
|
obj_wasted /= class->objs_per_zspage;
|
|
|
|
return obj_wasted * class->pages_per_zspage;
|
|
}
|
|
|
|
static void __zs_compact(struct zs_pool *pool, struct size_class *class)
|
|
{
|
|
struct zs_compact_control cc;
|
|
struct zspage *src_zspage;
|
|
struct zspage *dst_zspage = NULL;
|
|
|
|
spin_lock(&class->lock);
|
|
while ((src_zspage = isolate_zspage(class, true))) {
|
|
|
|
if (!zs_can_compact(class))
|
|
break;
|
|
|
|
cc.obj_idx = 0;
|
|
cc.s_page = get_first_page(src_zspage);
|
|
|
|
while ((dst_zspage = isolate_zspage(class, false))) {
|
|
cc.d_page = get_first_page(dst_zspage);
|
|
/*
|
|
* If there is no more space in dst_page, resched
|
|
* and see if anyone had allocated another zspage.
|
|
*/
|
|
if (!migrate_zspage(pool, class, &cc))
|
|
break;
|
|
|
|
putback_zspage(class, dst_zspage);
|
|
}
|
|
|
|
/* Stop if we couldn't find slot */
|
|
if (dst_zspage == NULL)
|
|
break;
|
|
|
|
putback_zspage(class, dst_zspage);
|
|
if (putback_zspage(class, src_zspage) == ZS_EMPTY) {
|
|
free_zspage(pool, class, src_zspage);
|
|
pool->stats.pages_compacted += class->pages_per_zspage;
|
|
}
|
|
spin_unlock(&class->lock);
|
|
cond_resched();
|
|
spin_lock(&class->lock);
|
|
}
|
|
|
|
if (src_zspage)
|
|
putback_zspage(class, src_zspage);
|
|
|
|
spin_unlock(&class->lock);
|
|
}
|
|
|
|
unsigned long zs_compact(struct zs_pool *pool)
|
|
{
|
|
int i;
|
|
struct size_class *class;
|
|
|
|
for (i = ZS_SIZE_CLASSES - 1; i >= 0; i--) {
|
|
class = pool->size_class[i];
|
|
if (!class)
|
|
continue;
|
|
if (class->index != i)
|
|
continue;
|
|
__zs_compact(pool, class);
|
|
}
|
|
|
|
return pool->stats.pages_compacted;
|
|
}
|
|
EXPORT_SYMBOL_GPL(zs_compact);
|
|
|
|
void zs_pool_stats(struct zs_pool *pool, struct zs_pool_stats *stats)
|
|
{
|
|
memcpy(stats, &pool->stats, sizeof(struct zs_pool_stats));
|
|
}
|
|
EXPORT_SYMBOL_GPL(zs_pool_stats);
|
|
|
|
static unsigned long zs_shrinker_scan(struct shrinker *shrinker,
|
|
struct shrink_control *sc)
|
|
{
|
|
unsigned long pages_freed;
|
|
struct zs_pool *pool = container_of(shrinker, struct zs_pool,
|
|
shrinker);
|
|
|
|
pages_freed = pool->stats.pages_compacted;
|
|
/*
|
|
* Compact classes and calculate compaction delta.
|
|
* Can run concurrently with a manually triggered
|
|
* (by user) compaction.
|
|
*/
|
|
pages_freed = zs_compact(pool) - pages_freed;
|
|
|
|
return pages_freed ? pages_freed : SHRINK_STOP;
|
|
}
|
|
|
|
static unsigned long zs_shrinker_count(struct shrinker *shrinker,
|
|
struct shrink_control *sc)
|
|
{
|
|
int i;
|
|
struct size_class *class;
|
|
unsigned long pages_to_free = 0;
|
|
struct zs_pool *pool = container_of(shrinker, struct zs_pool,
|
|
shrinker);
|
|
|
|
for (i = ZS_SIZE_CLASSES - 1; i >= 0; i--) {
|
|
class = pool->size_class[i];
|
|
if (!class)
|
|
continue;
|
|
if (class->index != i)
|
|
continue;
|
|
|
|
pages_to_free += zs_can_compact(class);
|
|
}
|
|
|
|
return pages_to_free;
|
|
}
|
|
|
|
static void zs_unregister_shrinker(struct zs_pool *pool)
|
|
{
|
|
unregister_shrinker(&pool->shrinker);
|
|
}
|
|
|
|
static int zs_register_shrinker(struct zs_pool *pool)
|
|
{
|
|
pool->shrinker.scan_objects = zs_shrinker_scan;
|
|
pool->shrinker.count_objects = zs_shrinker_count;
|
|
pool->shrinker.batch = 0;
|
|
pool->shrinker.seeks = DEFAULT_SEEKS;
|
|
|
|
return register_shrinker(&pool->shrinker);
|
|
}
|
|
|
|
/**
|
|
* zs_create_pool - Creates an allocation pool to work from.
|
|
* @name: pool name to be created
|
|
*
|
|
* This function must be called before anything when using
|
|
* the zsmalloc allocator.
|
|
*
|
|
* On success, a pointer to the newly created pool is returned,
|
|
* otherwise NULL.
|
|
*/
|
|
struct zs_pool *zs_create_pool(const char *name)
|
|
{
|
|
int i;
|
|
struct zs_pool *pool;
|
|
struct size_class *prev_class = NULL;
|
|
|
|
pool = kzalloc(sizeof(*pool), GFP_KERNEL);
|
|
if (!pool)
|
|
return NULL;
|
|
|
|
init_deferred_free(pool);
|
|
|
|
pool->name = kstrdup(name, GFP_KERNEL);
|
|
if (!pool->name)
|
|
goto err;
|
|
|
|
#ifdef CONFIG_COMPACTION
|
|
init_waitqueue_head(&pool->migration_wait);
|
|
#endif
|
|
|
|
if (create_cache(pool))
|
|
goto err;
|
|
|
|
/*
|
|
* Iterate reversely, because, size of size_class that we want to use
|
|
* for merging should be larger or equal to current size.
|
|
*/
|
|
for (i = ZS_SIZE_CLASSES - 1; i >= 0; i--) {
|
|
int size;
|
|
int pages_per_zspage;
|
|
int objs_per_zspage;
|
|
struct size_class *class;
|
|
int fullness = 0;
|
|
|
|
size = ZS_MIN_ALLOC_SIZE + i * ZS_SIZE_CLASS_DELTA;
|
|
if (size > ZS_MAX_ALLOC_SIZE)
|
|
size = ZS_MAX_ALLOC_SIZE;
|
|
pages_per_zspage = get_pages_per_zspage(size);
|
|
objs_per_zspage = pages_per_zspage * PAGE_SIZE / size;
|
|
|
|
/*
|
|
* We iterate from biggest down to smallest classes,
|
|
* so huge_class_size holds the size of the first huge
|
|
* class. Any object bigger than or equal to that will
|
|
* endup in the huge class.
|
|
*/
|
|
if (pages_per_zspage != 1 && objs_per_zspage != 1 &&
|
|
!huge_class_size) {
|
|
huge_class_size = size;
|
|
/*
|
|
* The object uses ZS_HANDLE_SIZE bytes to store the
|
|
* handle. We need to subtract it, because zs_malloc()
|
|
* unconditionally adds handle size before it performs
|
|
* size class search - so object may be smaller than
|
|
* huge class size, yet it still can end up in the huge
|
|
* class because it grows by ZS_HANDLE_SIZE extra bytes
|
|
* right before class lookup.
|
|
*/
|
|
huge_class_size -= (ZS_HANDLE_SIZE - 1);
|
|
}
|
|
|
|
/*
|
|
* size_class is used for normal zsmalloc operation such
|
|
* as alloc/free for that size. Although it is natural that we
|
|
* have one size_class for each size, there is a chance that we
|
|
* can get more memory utilization if we use one size_class for
|
|
* many different sizes whose size_class have same
|
|
* characteristics. So, we makes size_class point to
|
|
* previous size_class if possible.
|
|
*/
|
|
if (prev_class) {
|
|
if (can_merge(prev_class, pages_per_zspage, objs_per_zspage)) {
|
|
pool->size_class[i] = prev_class;
|
|
continue;
|
|
}
|
|
}
|
|
|
|
class = kzalloc(sizeof(struct size_class), GFP_KERNEL);
|
|
if (!class)
|
|
goto err;
|
|
|
|
class->size = size;
|
|
class->index = i;
|
|
class->pages_per_zspage = pages_per_zspage;
|
|
class->objs_per_zspage = objs_per_zspage;
|
|
spin_lock_init(&class->lock);
|
|
pool->size_class[i] = class;
|
|
for (fullness = ZS_EMPTY; fullness < NR_ZS_FULLNESS;
|
|
fullness++)
|
|
INIT_LIST_HEAD(&class->fullness_list[fullness]);
|
|
|
|
prev_class = class;
|
|
}
|
|
|
|
/* debug only, don't abort if it fails */
|
|
zs_pool_stat_create(pool, name);
|
|
|
|
if (zs_register_migration(pool))
|
|
goto err;
|
|
|
|
/*
|
|
* Not critical since shrinker is only used to trigger internal
|
|
* defragmentation of the pool which is pretty optional thing. If
|
|
* registration fails we still can use the pool normally and user can
|
|
* trigger compaction manually. Thus, ignore return code.
|
|
*/
|
|
zs_register_shrinker(pool);
|
|
|
|
return pool;
|
|
|
|
err:
|
|
zs_destroy_pool(pool);
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL_GPL(zs_create_pool);
|
|
|
|
void zs_destroy_pool(struct zs_pool *pool)
|
|
{
|
|
int i;
|
|
|
|
zs_unregister_shrinker(pool);
|
|
zs_unregister_migration(pool);
|
|
zs_pool_stat_destroy(pool);
|
|
|
|
for (i = 0; i < ZS_SIZE_CLASSES; i++) {
|
|
int fg;
|
|
struct size_class *class = pool->size_class[i];
|
|
|
|
if (!class)
|
|
continue;
|
|
|
|
if (class->index != i)
|
|
continue;
|
|
|
|
for (fg = ZS_EMPTY; fg < NR_ZS_FULLNESS; fg++) {
|
|
if (!list_empty(&class->fullness_list[fg])) {
|
|
pr_info("Freeing non-empty class with size %db, fullness group %d\n",
|
|
class->size, fg);
|
|
}
|
|
}
|
|
kfree(class);
|
|
}
|
|
|
|
destroy_cache(pool);
|
|
kfree(pool->name);
|
|
kfree(pool);
|
|
}
|
|
EXPORT_SYMBOL_GPL(zs_destroy_pool);
|
|
|
|
static int __init zs_init(void)
|
|
{
|
|
int ret;
|
|
|
|
ret = zsmalloc_mount();
|
|
if (ret)
|
|
goto out;
|
|
|
|
ret = cpuhp_setup_state(CPUHP_MM_ZS_PREPARE, "mm/zsmalloc:prepare",
|
|
zs_cpu_prepare, zs_cpu_dead);
|
|
if (ret)
|
|
goto hp_setup_fail;
|
|
|
|
#ifdef CONFIG_ZPOOL
|
|
zpool_register_driver(&zs_zpool_driver);
|
|
#endif
|
|
|
|
zs_stat_init();
|
|
|
|
return 0;
|
|
|
|
hp_setup_fail:
|
|
zsmalloc_unmount();
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static void __exit zs_exit(void)
|
|
{
|
|
#ifdef CONFIG_ZPOOL
|
|
zpool_unregister_driver(&zs_zpool_driver);
|
|
#endif
|
|
zsmalloc_unmount();
|
|
cpuhp_remove_state(CPUHP_MM_ZS_PREPARE);
|
|
|
|
zs_stat_exit();
|
|
}
|
|
|
|
module_init(zs_init);
|
|
module_exit(zs_exit);
|
|
|
|
MODULE_LICENSE("Dual BSD/GPL");
|
|
MODULE_AUTHOR("Nitin Gupta <ngupta@vflare.org>");
|