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synced 2024-08-23 01:10:04 +00:00
![Joonsoo Kim](/assets/img/avatar_default.png)
There is a memory waste problem if we define field on struct page_ext by hard-coding. Entry size of struct page_ext includes the size of those fields even if it is disabled at runtime. Now, extra memory request at runtime is possible so page_owner don't need to define it's own fields by hard-coding. This patch removes hard-coded define and uses extra memory for storing page_owner information in page_owner. Most of code are just mechanical changes. Link: http://lkml.kernel.org/r/1471315879-32294-7-git-send-email-iamjoonsoo.kim@lge.com Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Minchan Kim <minchan@kernel.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
623 lines
15 KiB
C
623 lines
15 KiB
C
#include <linux/debugfs.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/uaccess.h>
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#include <linux/bootmem.h>
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#include <linux/stacktrace.h>
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#include <linux/page_owner.h>
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#include <linux/jump_label.h>
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#include <linux/migrate.h>
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#include <linux/stackdepot.h>
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#include <linux/seq_file.h>
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#include "internal.h"
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/*
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* TODO: teach PAGE_OWNER_STACK_DEPTH (__dump_page_owner and save_stack)
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* to use off stack temporal storage
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*/
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#define PAGE_OWNER_STACK_DEPTH (16)
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struct page_owner {
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unsigned int order;
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gfp_t gfp_mask;
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int last_migrate_reason;
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depot_stack_handle_t handle;
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};
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static bool page_owner_disabled = true;
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DEFINE_STATIC_KEY_FALSE(page_owner_inited);
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static depot_stack_handle_t dummy_handle;
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static depot_stack_handle_t failure_handle;
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static void init_early_allocated_pages(void);
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static int early_page_owner_param(char *buf)
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{
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if (!buf)
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return -EINVAL;
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if (strcmp(buf, "on") == 0)
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page_owner_disabled = false;
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return 0;
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}
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early_param("page_owner", early_page_owner_param);
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static bool need_page_owner(void)
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{
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if (page_owner_disabled)
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return false;
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return true;
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}
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static noinline void register_dummy_stack(void)
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{
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unsigned long entries[4];
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struct stack_trace dummy;
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dummy.nr_entries = 0;
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dummy.max_entries = ARRAY_SIZE(entries);
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dummy.entries = &entries[0];
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dummy.skip = 0;
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save_stack_trace(&dummy);
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dummy_handle = depot_save_stack(&dummy, GFP_KERNEL);
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}
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static noinline void register_failure_stack(void)
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{
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unsigned long entries[4];
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struct stack_trace failure;
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failure.nr_entries = 0;
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failure.max_entries = ARRAY_SIZE(entries);
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failure.entries = &entries[0];
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failure.skip = 0;
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save_stack_trace(&failure);
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failure_handle = depot_save_stack(&failure, GFP_KERNEL);
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}
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static void init_page_owner(void)
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{
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if (page_owner_disabled)
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return;
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register_dummy_stack();
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register_failure_stack();
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static_branch_enable(&page_owner_inited);
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init_early_allocated_pages();
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}
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struct page_ext_operations page_owner_ops = {
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.size = sizeof(struct page_owner),
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.need = need_page_owner,
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.init = init_page_owner,
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};
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static inline struct page_owner *get_page_owner(struct page_ext *page_ext)
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{
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return (void *)page_ext + page_owner_ops.offset;
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}
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void __reset_page_owner(struct page *page, unsigned int order)
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{
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int i;
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struct page_ext *page_ext;
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for (i = 0; i < (1 << order); i++) {
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page_ext = lookup_page_ext(page + i);
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if (unlikely(!page_ext))
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continue;
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__clear_bit(PAGE_EXT_OWNER, &page_ext->flags);
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}
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}
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static inline bool check_recursive_alloc(struct stack_trace *trace,
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unsigned long ip)
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{
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int i, count;
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if (!trace->nr_entries)
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return false;
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for (i = 0, count = 0; i < trace->nr_entries; i++) {
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if (trace->entries[i] == ip && ++count == 2)
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return true;
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}
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return false;
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}
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static noinline depot_stack_handle_t save_stack(gfp_t flags)
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{
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unsigned long entries[PAGE_OWNER_STACK_DEPTH];
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struct stack_trace trace = {
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.nr_entries = 0,
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.entries = entries,
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.max_entries = PAGE_OWNER_STACK_DEPTH,
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.skip = 0
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};
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depot_stack_handle_t handle;
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save_stack_trace(&trace);
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if (trace.nr_entries != 0 &&
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trace.entries[trace.nr_entries-1] == ULONG_MAX)
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trace.nr_entries--;
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/*
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* We need to check recursion here because our request to stackdepot
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* could trigger memory allocation to save new entry. New memory
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* allocation would reach here and call depot_save_stack() again
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* if we don't catch it. There is still not enough memory in stackdepot
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* so it would try to allocate memory again and loop forever.
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*/
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if (check_recursive_alloc(&trace, _RET_IP_))
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return dummy_handle;
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handle = depot_save_stack(&trace, flags);
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if (!handle)
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handle = failure_handle;
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return handle;
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}
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noinline void __set_page_owner(struct page *page, unsigned int order,
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gfp_t gfp_mask)
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{
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struct page_ext *page_ext = lookup_page_ext(page);
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struct page_owner *page_owner;
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if (unlikely(!page_ext))
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return;
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page_owner = get_page_owner(page_ext);
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page_owner->handle = save_stack(gfp_mask);
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page_owner->order = order;
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page_owner->gfp_mask = gfp_mask;
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page_owner->last_migrate_reason = -1;
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__set_bit(PAGE_EXT_OWNER, &page_ext->flags);
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}
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void __set_page_owner_migrate_reason(struct page *page, int reason)
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{
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struct page_ext *page_ext = lookup_page_ext(page);
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struct page_owner *page_owner;
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if (unlikely(!page_ext))
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return;
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page_owner = get_page_owner(page_ext);
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page_owner->last_migrate_reason = reason;
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}
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void __split_page_owner(struct page *page, unsigned int order)
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{
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int i;
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struct page_ext *page_ext = lookup_page_ext(page);
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struct page_owner *page_owner;
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if (unlikely(!page_ext))
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return;
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page_owner = get_page_owner(page_ext);
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page_owner->order = 0;
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for (i = 1; i < (1 << order); i++)
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__copy_page_owner(page, page + i);
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}
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void __copy_page_owner(struct page *oldpage, struct page *newpage)
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{
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struct page_ext *old_ext = lookup_page_ext(oldpage);
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struct page_ext *new_ext = lookup_page_ext(newpage);
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struct page_owner *old_page_owner, *new_page_owner;
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if (unlikely(!old_ext || !new_ext))
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return;
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old_page_owner = get_page_owner(old_ext);
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new_page_owner = get_page_owner(new_ext);
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new_page_owner->order = old_page_owner->order;
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new_page_owner->gfp_mask = old_page_owner->gfp_mask;
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new_page_owner->last_migrate_reason =
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old_page_owner->last_migrate_reason;
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new_page_owner->handle = old_page_owner->handle;
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/*
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* We don't clear the bit on the oldpage as it's going to be freed
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* after migration. Until then, the info can be useful in case of
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* a bug, and the overal stats will be off a bit only temporarily.
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* Also, migrate_misplaced_transhuge_page() can still fail the
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* migration and then we want the oldpage to retain the info. But
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* in that case we also don't need to explicitly clear the info from
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* the new page, which will be freed.
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*/
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__set_bit(PAGE_EXT_OWNER, &new_ext->flags);
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}
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void pagetypeinfo_showmixedcount_print(struct seq_file *m,
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pg_data_t *pgdat, struct zone *zone)
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{
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struct page *page;
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struct page_ext *page_ext;
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struct page_owner *page_owner;
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unsigned long pfn = zone->zone_start_pfn, block_end_pfn;
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unsigned long end_pfn = pfn + zone->spanned_pages;
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unsigned long count[MIGRATE_TYPES] = { 0, };
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int pageblock_mt, page_mt;
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int i;
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/* Scan block by block. First and last block may be incomplete */
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pfn = zone->zone_start_pfn;
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/*
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* Walk the zone in pageblock_nr_pages steps. If a page block spans
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* a zone boundary, it will be double counted between zones. This does
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* not matter as the mixed block count will still be correct
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*/
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for (; pfn < end_pfn; ) {
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if (!pfn_valid(pfn)) {
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pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
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continue;
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}
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block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
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block_end_pfn = min(block_end_pfn, end_pfn);
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page = pfn_to_page(pfn);
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pageblock_mt = get_pageblock_migratetype(page);
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for (; pfn < block_end_pfn; pfn++) {
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if (!pfn_valid_within(pfn))
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continue;
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page = pfn_to_page(pfn);
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if (page_zone(page) != zone)
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continue;
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if (PageBuddy(page)) {
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pfn += (1UL << page_order(page)) - 1;
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continue;
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}
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if (PageReserved(page))
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continue;
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page_ext = lookup_page_ext(page);
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if (unlikely(!page_ext))
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continue;
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if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
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continue;
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page_owner = get_page_owner(page_ext);
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page_mt = gfpflags_to_migratetype(
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page_owner->gfp_mask);
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if (pageblock_mt != page_mt) {
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if (is_migrate_cma(pageblock_mt))
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count[MIGRATE_MOVABLE]++;
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else
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count[pageblock_mt]++;
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pfn = block_end_pfn;
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break;
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}
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pfn += (1UL << page_owner->order) - 1;
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}
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}
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/* Print counts */
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seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
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for (i = 0; i < MIGRATE_TYPES; i++)
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seq_printf(m, "%12lu ", count[i]);
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seq_putc(m, '\n');
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}
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static ssize_t
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print_page_owner(char __user *buf, size_t count, unsigned long pfn,
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struct page *page, struct page_owner *page_owner,
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depot_stack_handle_t handle)
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{
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int ret;
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int pageblock_mt, page_mt;
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char *kbuf;
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unsigned long entries[PAGE_OWNER_STACK_DEPTH];
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struct stack_trace trace = {
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.nr_entries = 0,
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.entries = entries,
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.max_entries = PAGE_OWNER_STACK_DEPTH,
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.skip = 0
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};
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kbuf = kmalloc(count, GFP_KERNEL);
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if (!kbuf)
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return -ENOMEM;
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ret = snprintf(kbuf, count,
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"Page allocated via order %u, mask %#x(%pGg)\n",
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page_owner->order, page_owner->gfp_mask,
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&page_owner->gfp_mask);
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if (ret >= count)
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goto err;
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/* Print information relevant to grouping pages by mobility */
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pageblock_mt = get_pageblock_migratetype(page);
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page_mt = gfpflags_to_migratetype(page_owner->gfp_mask);
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ret += snprintf(kbuf + ret, count - ret,
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"PFN %lu type %s Block %lu type %s Flags %#lx(%pGp)\n",
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pfn,
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migratetype_names[page_mt],
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pfn >> pageblock_order,
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migratetype_names[pageblock_mt],
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page->flags, &page->flags);
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if (ret >= count)
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goto err;
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depot_fetch_stack(handle, &trace);
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ret += snprint_stack_trace(kbuf + ret, count - ret, &trace, 0);
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if (ret >= count)
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goto err;
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if (page_owner->last_migrate_reason != -1) {
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ret += snprintf(kbuf + ret, count - ret,
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"Page has been migrated, last migrate reason: %s\n",
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migrate_reason_names[page_owner->last_migrate_reason]);
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if (ret >= count)
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goto err;
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}
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ret += snprintf(kbuf + ret, count - ret, "\n");
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if (ret >= count)
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goto err;
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if (copy_to_user(buf, kbuf, ret))
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ret = -EFAULT;
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kfree(kbuf);
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return ret;
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err:
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kfree(kbuf);
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return -ENOMEM;
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}
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void __dump_page_owner(struct page *page)
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{
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struct page_ext *page_ext = lookup_page_ext(page);
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struct page_owner *page_owner;
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unsigned long entries[PAGE_OWNER_STACK_DEPTH];
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struct stack_trace trace = {
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.nr_entries = 0,
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.entries = entries,
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.max_entries = PAGE_OWNER_STACK_DEPTH,
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.skip = 0
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};
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depot_stack_handle_t handle;
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gfp_t gfp_mask;
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int mt;
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if (unlikely(!page_ext)) {
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pr_alert("There is not page extension available.\n");
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return;
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}
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page_owner = get_page_owner(page_ext);
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gfp_mask = page_owner->gfp_mask;
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mt = gfpflags_to_migratetype(gfp_mask);
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if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) {
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pr_alert("page_owner info is not active (free page?)\n");
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return;
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}
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handle = READ_ONCE(page_owner->handle);
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if (!handle) {
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pr_alert("page_owner info is not active (free page?)\n");
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return;
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}
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depot_fetch_stack(handle, &trace);
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pr_alert("page allocated via order %u, migratetype %s, gfp_mask %#x(%pGg)\n",
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page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask);
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print_stack_trace(&trace, 0);
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if (page_owner->last_migrate_reason != -1)
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pr_alert("page has been migrated, last migrate reason: %s\n",
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migrate_reason_names[page_owner->last_migrate_reason]);
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}
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static ssize_t
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read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
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{
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unsigned long pfn;
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struct page *page;
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struct page_ext *page_ext;
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struct page_owner *page_owner;
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depot_stack_handle_t handle;
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if (!static_branch_unlikely(&page_owner_inited))
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return -EINVAL;
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page = NULL;
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pfn = min_low_pfn + *ppos;
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/* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */
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while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0)
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pfn++;
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drain_all_pages(NULL);
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/* Find an allocated page */
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for (; pfn < max_pfn; pfn++) {
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/*
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* If the new page is in a new MAX_ORDER_NR_PAGES area,
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* validate the area as existing, skip it if not
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*/
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if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) {
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pfn += MAX_ORDER_NR_PAGES - 1;
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continue;
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}
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|
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/* Check for holes within a MAX_ORDER area */
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if (!pfn_valid_within(pfn))
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continue;
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page = pfn_to_page(pfn);
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if (PageBuddy(page)) {
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unsigned long freepage_order = page_order_unsafe(page);
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|
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if (freepage_order < MAX_ORDER)
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pfn += (1UL << freepage_order) - 1;
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continue;
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}
|
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|
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page_ext = lookup_page_ext(page);
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if (unlikely(!page_ext))
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continue;
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|
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/*
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* Some pages could be missed by concurrent allocation or free,
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* because we don't hold the zone lock.
|
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*/
|
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if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
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continue;
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|
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page_owner = get_page_owner(page_ext);
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|
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/*
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* Access to page_ext->handle isn't synchronous so we should
|
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* be careful to access it.
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*/
|
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handle = READ_ONCE(page_owner->handle);
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if (!handle)
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continue;
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|
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/* Record the next PFN to read in the file offset */
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*ppos = (pfn - min_low_pfn) + 1;
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|
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return print_page_owner(buf, count, pfn, page,
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page_owner, handle);
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}
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|
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return 0;
|
|
}
|
|
|
|
static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
|
|
{
|
|
struct page *page;
|
|
struct page_ext *page_ext;
|
|
unsigned long pfn = zone->zone_start_pfn, block_end_pfn;
|
|
unsigned long end_pfn = pfn + zone->spanned_pages;
|
|
unsigned long count = 0;
|
|
|
|
/* Scan block by block. First and last block may be incomplete */
|
|
pfn = zone->zone_start_pfn;
|
|
|
|
/*
|
|
* Walk the zone in pageblock_nr_pages steps. If a page block spans
|
|
* a zone boundary, it will be double counted between zones. This does
|
|
* not matter as the mixed block count will still be correct
|
|
*/
|
|
for (; pfn < end_pfn; ) {
|
|
if (!pfn_valid(pfn)) {
|
|
pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
|
|
continue;
|
|
}
|
|
|
|
block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
|
|
block_end_pfn = min(block_end_pfn, end_pfn);
|
|
|
|
page = pfn_to_page(pfn);
|
|
|
|
for (; pfn < block_end_pfn; pfn++) {
|
|
if (!pfn_valid_within(pfn))
|
|
continue;
|
|
|
|
page = pfn_to_page(pfn);
|
|
|
|
if (page_zone(page) != zone)
|
|
continue;
|
|
|
|
/*
|
|
* We are safe to check buddy flag and order, because
|
|
* this is init stage and only single thread runs.
|
|
*/
|
|
if (PageBuddy(page)) {
|
|
pfn += (1UL << page_order(page)) - 1;
|
|
continue;
|
|
}
|
|
|
|
if (PageReserved(page))
|
|
continue;
|
|
|
|
page_ext = lookup_page_ext(page);
|
|
if (unlikely(!page_ext))
|
|
continue;
|
|
|
|
/* Maybe overraping zone */
|
|
if (test_bit(PAGE_EXT_OWNER, &page_ext->flags))
|
|
continue;
|
|
|
|
/* Found early allocated page */
|
|
set_page_owner(page, 0, 0);
|
|
count++;
|
|
}
|
|
}
|
|
|
|
pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n",
|
|
pgdat->node_id, zone->name, count);
|
|
}
|
|
|
|
static void init_zones_in_node(pg_data_t *pgdat)
|
|
{
|
|
struct zone *zone;
|
|
struct zone *node_zones = pgdat->node_zones;
|
|
unsigned long flags;
|
|
|
|
for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
|
|
if (!populated_zone(zone))
|
|
continue;
|
|
|
|
spin_lock_irqsave(&zone->lock, flags);
|
|
init_pages_in_zone(pgdat, zone);
|
|
spin_unlock_irqrestore(&zone->lock, flags);
|
|
}
|
|
}
|
|
|
|
static void init_early_allocated_pages(void)
|
|
{
|
|
pg_data_t *pgdat;
|
|
|
|
drain_all_pages(NULL);
|
|
for_each_online_pgdat(pgdat)
|
|
init_zones_in_node(pgdat);
|
|
}
|
|
|
|
static const struct file_operations proc_page_owner_operations = {
|
|
.read = read_page_owner,
|
|
};
|
|
|
|
static int __init pageowner_init(void)
|
|
{
|
|
struct dentry *dentry;
|
|
|
|
if (!static_branch_unlikely(&page_owner_inited)) {
|
|
pr_info("page_owner is disabled\n");
|
|
return 0;
|
|
}
|
|
|
|
dentry = debugfs_create_file("page_owner", S_IRUSR, NULL,
|
|
NULL, &proc_page_owner_operations);
|
|
if (IS_ERR(dentry))
|
|
return PTR_ERR(dentry);
|
|
|
|
return 0;
|
|
}
|
|
late_initcall(pageowner_init)
|