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linux-stable/drivers/staging/ramster/zcache-main.c
Linus Torvalds a3fe778c78 Frontswap provides a "transcendent memory" interface for swap pages. 
In some environments, dramatic performance savings may be obtained because
 swapped pages are saved in RAM (or a RAM-like device) instead of a swap disk.
 This tag provides the basic infrastructure along with some changes to the
 existing backends.
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Merge tag 'stable/frontswap.v16-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/mm

Pull frontswap feature from Konrad Rzeszutek Wilk:
 "Frontswap provides a "transcendent memory" interface for swap pages.
  In some environments, dramatic performance savings may be obtained
  because swapped pages are saved in RAM (or a RAM-like device) instead
  of a swap disk.  This tag provides the basic infrastructure along with
  some changes to the existing backends."

Fix up trivial conflict in mm/Makefile due to removal of swap token code
changing a line next to the new frontswap entry.

This pull request came in before the merge window even opened, it got
delayed to after the merge window by me just wanting to make sure it had
actual users.  Apparently IBM is using this on their embedded side, and
Jan Beulich says that it's already made available for SLES and OpenSUSE
users.

Also acked by Rik van Riel, and Konrad points to other people liking it
too.  So in it goes.

By Dan Magenheimer (4) and Konrad Rzeszutek Wilk (2)
via Konrad Rzeszutek Wilk
* tag 'stable/frontswap.v16-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/mm:
  frontswap: s/put_page/store/g s/get_page/load
  MAINTAINER: Add myself for the frontswap API
  mm: frontswap: config and doc files
  mm: frontswap: core frontswap functionality
  mm: frontswap: core swap subsystem hooks and headers
  mm: frontswap: add frontswap header file
2012-06-04 12:28:45 -07:00

3320 lines
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/*
* zcache.c
*
* Copyright (c) 2010-2012, Dan Magenheimer, Oracle Corp.
* Copyright (c) 2010,2011, Nitin Gupta
*
* Zcache provides an in-kernel "host implementation" for transcendent memory
* and, thus indirectly, for cleancache and frontswap. Zcache includes two
* page-accessible memory [1] interfaces, both utilizing lzo1x compression:
* 1) "compression buddies" ("zbud") is used for ephemeral pages
* 2) xvmalloc is used for persistent pages.
* Xvmalloc (based on the TLSF allocator) has very low fragmentation
* so maximizes space efficiency, while zbud allows pairs (and potentially,
* in the future, more than a pair of) compressed pages to be closely linked
* so that reclaiming can be done via the kernel's physical-page-oriented
* "shrinker" interface.
*
* [1] For a definition of page-accessible memory (aka PAM), see:
* http://marc.info/?l=linux-mm&m=127811271605009
* RAMSTER TODO:
* - handle remotifying of buddied pages (see zbud_remotify_zbpg)
* - kernel boot params: nocleancache/nofrontswap don't always work?!?
*/
#include <linux/module.h>
#include <linux/cpu.h>
#include <linux/highmem.h>
#include <linux/list.h>
#include <linux/lzo.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/types.h>
#include <linux/atomic.h>
#include <linux/math64.h>
#include "tmem.h"
#include "zcache.h"
#include "ramster.h"
#include "cluster/tcp.h"
#include "xvmalloc.h" /* temporary until change to zsmalloc */
#define RAMSTER_TESTING
#if (!defined(CONFIG_CLEANCACHE) && !defined(CONFIG_FRONTSWAP))
#error "ramster is useless without CONFIG_CLEANCACHE or CONFIG_FRONTSWAP"
#endif
#ifdef CONFIG_CLEANCACHE
#include <linux/cleancache.h>
#endif
#ifdef CONFIG_FRONTSWAP
#include <linux/frontswap.h>
#endif
enum ramster_remotify_op {
RAMSTER_REMOTIFY_EPH_PUT,
RAMSTER_REMOTIFY_PERS_PUT,
RAMSTER_REMOTIFY_FLUSH_PAGE,
RAMSTER_REMOTIFY_FLUSH_OBJ,
RAMSTER_INTRANSIT_PERS
};
struct ramster_remotify_hdr {
enum ramster_remotify_op op;
struct list_head list;
};
#define ZBH_SENTINEL 0x43214321
#define ZBPG_SENTINEL 0xdeadbeef
#define ZBUD_MAX_BUDS 2
struct zbud_hdr {
struct ramster_remotify_hdr rem_op;
uint16_t client_id;
uint16_t pool_id;
struct tmem_oid oid;
uint32_t index;
uint16_t size; /* compressed size in bytes, zero means unused */
DECL_SENTINEL
};
#define ZVH_SENTINEL 0x43214321
static const int zv_max_page_size = (PAGE_SIZE / 8) * 7;
struct zv_hdr {
struct ramster_remotify_hdr rem_op;
uint16_t client_id;
uint16_t pool_id;
struct tmem_oid oid;
uint32_t index;
DECL_SENTINEL
};
struct flushlist_node {
struct ramster_remotify_hdr rem_op;
struct tmem_xhandle xh;
};
union {
struct ramster_remotify_hdr rem_op;
struct zv_hdr zv;
struct zbud_hdr zbud;
struct flushlist_node flist;
} remotify_list_node;
static LIST_HEAD(zcache_rem_op_list);
static DEFINE_SPINLOCK(zcache_rem_op_list_lock);
#if 0
/* this is more aggressive but may cause other problems? */
#define ZCACHE_GFP_MASK (GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN)
#else
#define ZCACHE_GFP_MASK \
(__GFP_FS | __GFP_NORETRY | __GFP_NOWARN | __GFP_NOMEMALLOC)
#endif
#define MAX_POOLS_PER_CLIENT 16
#define MAX_CLIENTS 16
#define LOCAL_CLIENT ((uint16_t)-1)
MODULE_LICENSE("GPL");
struct zcache_client {
struct tmem_pool *tmem_pools[MAX_POOLS_PER_CLIENT];
struct xv_pool *xvpool;
bool allocated;
atomic_t refcount;
};
static struct zcache_client zcache_host;
static struct zcache_client zcache_clients[MAX_CLIENTS];
static inline uint16_t get_client_id_from_client(struct zcache_client *cli)
{
BUG_ON(cli == NULL);
if (cli == &zcache_host)
return LOCAL_CLIENT;
return cli - &zcache_clients[0];
}
static inline bool is_local_client(struct zcache_client *cli)
{
return cli == &zcache_host;
}
/**********
* Compression buddies ("zbud") provides for packing two (or, possibly
* in the future, more) compressed ephemeral pages into a single "raw"
* (physical) page and tracking them with data structures so that
* the raw pages can be easily reclaimed.
*
* A zbud page ("zbpg") is an aligned page containing a list_head,
* a lock, and two "zbud headers". The remainder of the physical
* page is divided up into aligned 64-byte "chunks" which contain
* the compressed data for zero, one, or two zbuds. Each zbpg
* resides on: (1) an "unused list" if it has no zbuds; (2) a
* "buddied" list if it is fully populated with two zbuds; or
* (3) one of PAGE_SIZE/64 "unbuddied" lists indexed by how many chunks
* the one unbuddied zbud uses. The data inside a zbpg cannot be
* read or written unless the zbpg's lock is held.
*/
struct zbud_page {
struct list_head bud_list;
spinlock_t lock;
struct zbud_hdr buddy[ZBUD_MAX_BUDS];
DECL_SENTINEL
/* followed by NUM_CHUNK aligned CHUNK_SIZE-byte chunks */
};
#define CHUNK_SHIFT 6
#define CHUNK_SIZE (1 << CHUNK_SHIFT)
#define CHUNK_MASK (~(CHUNK_SIZE-1))
#define NCHUNKS (((PAGE_SIZE - sizeof(struct zbud_page)) & \
CHUNK_MASK) >> CHUNK_SHIFT)
#define MAX_CHUNK (NCHUNKS-1)
static struct {
struct list_head list;
unsigned count;
} zbud_unbuddied[NCHUNKS];
/* list N contains pages with N chunks USED and NCHUNKS-N unused */
/* element 0 is never used but optimizing that isn't worth it */
static unsigned long zbud_cumul_chunk_counts[NCHUNKS];
struct list_head zbud_buddied_list;
static unsigned long zcache_zbud_buddied_count;
/* protects the buddied list and all unbuddied lists */
static DEFINE_SPINLOCK(zbud_budlists_spinlock);
static atomic_t zcache_zbud_curr_raw_pages;
static atomic_t zcache_zbud_curr_zpages;
static unsigned long zcache_zbud_curr_zbytes;
static unsigned long zcache_zbud_cumul_zpages;
static unsigned long zcache_zbud_cumul_zbytes;
static unsigned long zcache_compress_poor;
static unsigned long zcache_policy_percent_exceeded;
static unsigned long zcache_mean_compress_poor;
/*
* RAMster counters
* - Remote pages are pages with a local pampd but the data is remote
* - Foreign pages are pages stored locally but belonging to another node
*/
static atomic_t ramster_remote_pers_pages = ATOMIC_INIT(0);
static unsigned long ramster_pers_remotify_enable;
static unsigned long ramster_eph_remotify_enable;
static unsigned long ramster_eph_pages_remoted;
static unsigned long ramster_eph_pages_remote_failed;
static unsigned long ramster_pers_pages_remoted;
static unsigned long ramster_pers_pages_remote_failed;
static unsigned long ramster_pers_pages_remote_nomem;
static unsigned long ramster_remote_objects_flushed;
static unsigned long ramster_remote_object_flushes_failed;
static unsigned long ramster_remote_pages_flushed;
static unsigned long ramster_remote_page_flushes_failed;
static unsigned long ramster_remote_eph_pages_succ_get;
static unsigned long ramster_remote_pers_pages_succ_get;
static unsigned long ramster_remote_eph_pages_unsucc_get;
static unsigned long ramster_remote_pers_pages_unsucc_get;
static atomic_t ramster_curr_flnode_count = ATOMIC_INIT(0);
static unsigned long ramster_curr_flnode_count_max;
static atomic_t ramster_foreign_eph_pampd_count = ATOMIC_INIT(0);
static unsigned long ramster_foreign_eph_pampd_count_max;
static atomic_t ramster_foreign_pers_pampd_count = ATOMIC_INIT(0);
static unsigned long ramster_foreign_pers_pampd_count_max;
/* forward references */
static void *zcache_get_free_page(void);
static void zcache_free_page(void *p);
/*
* zbud helper functions
*/
static inline unsigned zbud_max_buddy_size(void)
{
return MAX_CHUNK << CHUNK_SHIFT;
}
static inline unsigned zbud_size_to_chunks(unsigned size)
{
BUG_ON(size == 0 || size > zbud_max_buddy_size());
return (size + CHUNK_SIZE - 1) >> CHUNK_SHIFT;
}
static inline int zbud_budnum(struct zbud_hdr *zh)
{
unsigned offset = (unsigned long)zh & (PAGE_SIZE - 1);
struct zbud_page *zbpg = NULL;
unsigned budnum = -1U;
int i;
for (i = 0; i < ZBUD_MAX_BUDS; i++)
if (offset == offsetof(typeof(*zbpg), buddy[i])) {
budnum = i;
break;
}
BUG_ON(budnum == -1U);
return budnum;
}
static char *zbud_data(struct zbud_hdr *zh, unsigned size)
{
struct zbud_page *zbpg;
char *p;
unsigned budnum;
ASSERT_SENTINEL(zh, ZBH);
budnum = zbud_budnum(zh);
BUG_ON(size == 0 || size > zbud_max_buddy_size());
zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
ASSERT_SPINLOCK(&zbpg->lock);
p = (char *)zbpg;
if (budnum == 0)
p += ((sizeof(struct zbud_page) + CHUNK_SIZE - 1) &
CHUNK_MASK);
else if (budnum == 1)
p += PAGE_SIZE - ((size + CHUNK_SIZE - 1) & CHUNK_MASK);
return p;
}
static void zbud_copy_from_pampd(char *data, size_t *size, struct zbud_hdr *zh)
{
struct zbud_page *zbpg;
char *p;
unsigned budnum;
ASSERT_SENTINEL(zh, ZBH);
budnum = zbud_budnum(zh);
zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
spin_lock(&zbpg->lock);
BUG_ON(zh->size > *size);
p = (char *)zbpg;
if (budnum == 0)
p += ((sizeof(struct zbud_page) + CHUNK_SIZE - 1) &
CHUNK_MASK);
else if (budnum == 1)
p += PAGE_SIZE - ((zh->size + CHUNK_SIZE - 1) & CHUNK_MASK);
/* client should be filled in by caller */
memcpy(data, p, zh->size);
*size = zh->size;
spin_unlock(&zbpg->lock);
}
/*
* zbud raw page management
*/
static struct zbud_page *zbud_alloc_raw_page(void)
{
struct zbud_page *zbpg = NULL;
struct zbud_hdr *zh0, *zh1;
zbpg = zcache_get_free_page();
if (likely(zbpg != NULL)) {
INIT_LIST_HEAD(&zbpg->bud_list);
zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1];
spin_lock_init(&zbpg->lock);
atomic_inc(&zcache_zbud_curr_raw_pages);
INIT_LIST_HEAD(&zbpg->bud_list);
SET_SENTINEL(zbpg, ZBPG);
zh0->size = 0; zh1->size = 0;
tmem_oid_set_invalid(&zh0->oid);
tmem_oid_set_invalid(&zh1->oid);
}
return zbpg;
}
static void zbud_free_raw_page(struct zbud_page *zbpg)
{
struct zbud_hdr *zh0 = &zbpg->buddy[0], *zh1 = &zbpg->buddy[1];
ASSERT_SENTINEL(zbpg, ZBPG);
BUG_ON(!list_empty(&zbpg->bud_list));
ASSERT_SPINLOCK(&zbpg->lock);
BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid));
BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid));
INVERT_SENTINEL(zbpg, ZBPG);
spin_unlock(&zbpg->lock);
atomic_dec(&zcache_zbud_curr_raw_pages);
zcache_free_page(zbpg);
}
/*
* core zbud handling routines
*/
static unsigned zbud_free(struct zbud_hdr *zh)
{
unsigned size;
ASSERT_SENTINEL(zh, ZBH);
BUG_ON(!tmem_oid_valid(&zh->oid));
size = zh->size;
BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size());
zh->size = 0;
tmem_oid_set_invalid(&zh->oid);
INVERT_SENTINEL(zh, ZBH);
zcache_zbud_curr_zbytes -= size;
atomic_dec(&zcache_zbud_curr_zpages);
return size;
}
static void zbud_free_and_delist(struct zbud_hdr *zh)
{
unsigned chunks;
struct zbud_hdr *zh_other;
unsigned budnum = zbud_budnum(zh), size;
struct zbud_page *zbpg =
container_of(zh, struct zbud_page, buddy[budnum]);
/* FIXME, should be BUG_ON, pool destruction path doesn't disable
* interrupts tmem_destroy_pool()->tmem_pampd_destroy_all_in_obj()->
* tmem_objnode_node_destroy()-> zcache_pampd_free() */
WARN_ON(!irqs_disabled());
spin_lock(&zbpg->lock);
if (list_empty(&zbpg->bud_list)) {
/* ignore zombie page... see zbud_evict_pages() */
spin_unlock(&zbpg->lock);
return;
}
size = zbud_free(zh);
ASSERT_SPINLOCK(&zbpg->lock);
zh_other = &zbpg->buddy[(budnum == 0) ? 1 : 0];
if (zh_other->size == 0) { /* was unbuddied: unlist and free */
chunks = zbud_size_to_chunks(size) ;
spin_lock(&zbud_budlists_spinlock);
BUG_ON(list_empty(&zbud_unbuddied[chunks].list));
list_del_init(&zbpg->bud_list);
zbud_unbuddied[chunks].count--;
spin_unlock(&zbud_budlists_spinlock);
zbud_free_raw_page(zbpg);
} else { /* was buddied: move remaining buddy to unbuddied list */
chunks = zbud_size_to_chunks(zh_other->size) ;
spin_lock(&zbud_budlists_spinlock);
list_del_init(&zbpg->bud_list);
zcache_zbud_buddied_count--;
list_add_tail(&zbpg->bud_list, &zbud_unbuddied[chunks].list);
zbud_unbuddied[chunks].count++;
spin_unlock(&zbud_budlists_spinlock);
spin_unlock(&zbpg->lock);
}
}
static struct zbud_hdr *zbud_create(uint16_t client_id, uint16_t pool_id,
struct tmem_oid *oid,
uint32_t index, struct page *page,
void *cdata, unsigned size)
{
struct zbud_hdr *zh0, *zh1, *zh = NULL;
struct zbud_page *zbpg = NULL, *ztmp;
unsigned nchunks;
char *to;
int i, found_good_buddy = 0;
nchunks = zbud_size_to_chunks(size) ;
for (i = MAX_CHUNK - nchunks + 1; i > 0; i--) {
spin_lock(&zbud_budlists_spinlock);
if (!list_empty(&zbud_unbuddied[i].list)) {
list_for_each_entry_safe(zbpg, ztmp,
&zbud_unbuddied[i].list, bud_list) {
if (spin_trylock(&zbpg->lock)) {
found_good_buddy = i;
goto found_unbuddied;
}
}
}
spin_unlock(&zbud_budlists_spinlock);
}
/* didn't find a good buddy, try allocating a new page */
zbpg = zbud_alloc_raw_page();
if (unlikely(zbpg == NULL))
goto out;
/* ok, have a page, now compress the data before taking locks */
spin_lock(&zbud_budlists_spinlock);
spin_lock(&zbpg->lock);
list_add_tail(&zbpg->bud_list, &zbud_unbuddied[nchunks].list);
zbud_unbuddied[nchunks].count++;
zh = &zbpg->buddy[0];
goto init_zh;
found_unbuddied:
ASSERT_SPINLOCK(&zbpg->lock);
zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1];
BUG_ON(!((zh0->size == 0) ^ (zh1->size == 0)));
if (zh0->size != 0) { /* buddy0 in use, buddy1 is vacant */
ASSERT_SENTINEL(zh0, ZBH);
zh = zh1;
} else if (zh1->size != 0) { /* buddy1 in use, buddy0 is vacant */
ASSERT_SENTINEL(zh1, ZBH);
zh = zh0;
} else
BUG();
list_del_init(&zbpg->bud_list);
zbud_unbuddied[found_good_buddy].count--;
list_add_tail(&zbpg->bud_list, &zbud_buddied_list);
zcache_zbud_buddied_count++;
init_zh:
SET_SENTINEL(zh, ZBH);
zh->size = size;
zh->index = index;
zh->oid = *oid;
zh->pool_id = pool_id;
zh->client_id = client_id;
to = zbud_data(zh, size);
memcpy(to, cdata, size);
spin_unlock(&zbpg->lock);
spin_unlock(&zbud_budlists_spinlock);
zbud_cumul_chunk_counts[nchunks]++;
atomic_inc(&zcache_zbud_curr_zpages);
zcache_zbud_cumul_zpages++;
zcache_zbud_curr_zbytes += size;
zcache_zbud_cumul_zbytes += size;
out:
return zh;
}
static int zbud_decompress(struct page *page, struct zbud_hdr *zh)
{
struct zbud_page *zbpg;
unsigned budnum = zbud_budnum(zh);
size_t out_len = PAGE_SIZE;
char *to_va, *from_va;
unsigned size;
int ret = 0;
zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
spin_lock(&zbpg->lock);
if (list_empty(&zbpg->bud_list)) {
/* ignore zombie page... see zbud_evict_pages() */
ret = -EINVAL;
goto out;
}
ASSERT_SENTINEL(zh, ZBH);
BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size());
to_va = kmap_atomic(page);
size = zh->size;
from_va = zbud_data(zh, size);
ret = lzo1x_decompress_safe(from_va, size, to_va, &out_len);
BUG_ON(ret != LZO_E_OK);
BUG_ON(out_len != PAGE_SIZE);
kunmap_atomic(to_va);
out:
spin_unlock(&zbpg->lock);
return ret;
}
/*
* The following routines handle shrinking of ephemeral pages by evicting
* pages "least valuable" first.
*/
static unsigned long zcache_evicted_raw_pages;
static unsigned long zcache_evicted_buddied_pages;
static unsigned long zcache_evicted_unbuddied_pages;
static struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id,
uint16_t poolid);
static void zcache_put_pool(struct tmem_pool *pool);
/*
* Flush and free all zbuds in a zbpg, then free the pageframe
*/
static void zbud_evict_zbpg(struct zbud_page *zbpg)
{
struct zbud_hdr *zh;
int i, j;
uint32_t pool_id[ZBUD_MAX_BUDS], client_id[ZBUD_MAX_BUDS];
uint32_t index[ZBUD_MAX_BUDS];
struct tmem_oid oid[ZBUD_MAX_BUDS];
struct tmem_pool *pool;
unsigned long flags;
ASSERT_SPINLOCK(&zbpg->lock);
for (i = 0, j = 0; i < ZBUD_MAX_BUDS; i++) {
zh = &zbpg->buddy[i];
if (zh->size) {
client_id[j] = zh->client_id;
pool_id[j] = zh->pool_id;
oid[j] = zh->oid;
index[j] = zh->index;
j++;
}
}
spin_unlock(&zbpg->lock);
for (i = 0; i < j; i++) {
pool = zcache_get_pool_by_id(client_id[i], pool_id[i]);
BUG_ON(pool == NULL);
local_irq_save(flags);
/* these flushes should dispose of any local storage */
tmem_flush_page(pool, &oid[i], index[i]);
local_irq_restore(flags);
zcache_put_pool(pool);
}
}
/*
* Free nr pages. This code is funky because we want to hold the locks
* protecting various lists for as short a time as possible, and in some
* circumstances the list may change asynchronously when the list lock is
* not held. In some cases we also trylock not only to avoid waiting on a
* page in use by another cpu, but also to avoid potential deadlock due to
* lock inversion.
*/
static void zbud_evict_pages(int nr)
{
struct zbud_page *zbpg;
int i, newly_unused_pages = 0;
/* now try freeing unbuddied pages, starting with least space avail */
for (i = 0; i < MAX_CHUNK; i++) {
retry_unbud_list_i:
spin_lock_bh(&zbud_budlists_spinlock);
if (list_empty(&zbud_unbuddied[i].list)) {
spin_unlock_bh(&zbud_budlists_spinlock);
continue;
}
list_for_each_entry(zbpg, &zbud_unbuddied[i].list, bud_list) {
if (unlikely(!spin_trylock(&zbpg->lock)))
continue;
zbud_unbuddied[i].count--;
spin_unlock(&zbud_budlists_spinlock);
zcache_evicted_unbuddied_pages++;
/* want budlists unlocked when doing zbpg eviction */
zbud_evict_zbpg(zbpg);
newly_unused_pages++;
local_bh_enable();
if (--nr <= 0)
goto evict_unused;
goto retry_unbud_list_i;
}
spin_unlock_bh(&zbud_budlists_spinlock);
}
/* as a last resort, free buddied pages */
retry_bud_list:
spin_lock_bh(&zbud_budlists_spinlock);
if (list_empty(&zbud_buddied_list)) {
spin_unlock_bh(&zbud_budlists_spinlock);
goto evict_unused;
}
list_for_each_entry(zbpg, &zbud_buddied_list, bud_list) {
if (unlikely(!spin_trylock(&zbpg->lock)))
continue;
zcache_zbud_buddied_count--;
spin_unlock(&zbud_budlists_spinlock);
zcache_evicted_buddied_pages++;
/* want budlists unlocked when doing zbpg eviction */
zbud_evict_zbpg(zbpg);
newly_unused_pages++;
local_bh_enable();
if (--nr <= 0)
goto evict_unused;
goto retry_bud_list;
}
spin_unlock_bh(&zbud_budlists_spinlock);
evict_unused:
return;
}
static DEFINE_PER_CPU(unsigned char *, zcache_remoteputmem);
static int zbud_remotify_zbud(struct tmem_xhandle *xh, char *data,
size_t size)
{
struct tmem_pool *pool;
int i, remotenode, ret = -1;
unsigned char cksum, *p;
unsigned long flags;
for (p = data, cksum = 0, i = 0; i < size; i++)
cksum += *p;
ret = ramster_remote_put(xh, data, size, true, &remotenode);
if (ret == 0) {
/* data was successfully remoted so change the local version
* to point to the remote node where it landed */
pool = zcache_get_pool_by_id(LOCAL_CLIENT, xh->pool_id);
BUG_ON(pool == NULL);
local_irq_save(flags);
/* tmem_replace will also free up any local space */
(void)tmem_replace(pool, &xh->oid, xh->index,
pampd_make_remote(remotenode, size, cksum));
local_irq_restore(flags);
zcache_put_pool(pool);
ramster_eph_pages_remoted++;
ret = 0;
} else
ramster_eph_pages_remote_failed++;
return ret;
}
static int zbud_remotify_zbpg(struct zbud_page *zbpg)
{
struct zbud_hdr *zh1, *zh2 = NULL;
struct tmem_xhandle xh1, xh2 = { 0 };
char *data1 = NULL, *data2 = NULL;
size_t size1 = 0, size2 = 0;
int ret = 0;
unsigned char *tmpmem = __get_cpu_var(zcache_remoteputmem);
ASSERT_SPINLOCK(&zbpg->lock);
if (zbpg->buddy[0].size == 0)
zh1 = &zbpg->buddy[1];
else if (zbpg->buddy[1].size == 0)
zh1 = &zbpg->buddy[0];
else {
zh1 = &zbpg->buddy[0];
zh2 = &zbpg->buddy[1];
}
/* don't remotify pages that are already remotified */
if (zh1->client_id != LOCAL_CLIENT)
zh1 = NULL;
if ((zh2 != NULL) && (zh2->client_id != LOCAL_CLIENT))
zh2 = NULL;
/* copy the data and metadata so can release lock */
if (zh1 != NULL) {
xh1.client_id = zh1->client_id;
xh1.pool_id = zh1->pool_id;
xh1.oid = zh1->oid;
xh1.index = zh1->index;
size1 = zh1->size;
data1 = zbud_data(zh1, size1);
memcpy(tmpmem, zbud_data(zh1, size1), size1);
data1 = tmpmem;
tmpmem += size1;
}
if (zh2 != NULL) {
xh2.client_id = zh2->client_id;
xh2.pool_id = zh2->pool_id;
xh2.oid = zh2->oid;
xh2.index = zh2->index;
size2 = zh2->size;
memcpy(tmpmem, zbud_data(zh2, size2), size2);
data2 = tmpmem;
}
spin_unlock(&zbpg->lock);
preempt_enable();
/* OK, no locks held anymore, remotify one or both zbuds */
if (zh1 != NULL)
ret = zbud_remotify_zbud(&xh1, data1, size1);
if (zh2 != NULL)
ret |= zbud_remotify_zbud(&xh2, data2, size2);
return ret;
}
void zbud_remotify_pages(int nr)
{
struct zbud_page *zbpg;
int i, ret;
/*
* for now just try remotifying unbuddied pages, starting with
* least space avail
*/
for (i = 0; i < MAX_CHUNK; i++) {
retry_unbud_list_i:
preempt_disable(); /* enable in zbud_remotify_zbpg */
spin_lock_bh(&zbud_budlists_spinlock);
if (list_empty(&zbud_unbuddied[i].list)) {
spin_unlock_bh(&zbud_budlists_spinlock);
preempt_enable();
continue; /* next i in for loop */
}
list_for_each_entry(zbpg, &zbud_unbuddied[i].list, bud_list) {
if (unlikely(!spin_trylock(&zbpg->lock)))
continue; /* next list_for_each_entry */
zbud_unbuddied[i].count--;
/* want budlists unlocked when doing zbpg remotify */
spin_unlock_bh(&zbud_budlists_spinlock);
ret = zbud_remotify_zbpg(zbpg);
/* preemption is re-enabled in zbud_remotify_zbpg */
if (ret == 0) {
if (--nr <= 0)
goto out;
goto retry_unbud_list_i;
}
/* if fail to remotify any page, quit */
pr_err("TESTING zbud_remotify_pages failed on page,"
" trying to re-add\n");
spin_lock_bh(&zbud_budlists_spinlock);
spin_lock(&zbpg->lock);
list_add_tail(&zbpg->bud_list, &zbud_unbuddied[i].list);
zbud_unbuddied[i].count++;
spin_unlock(&zbpg->lock);
spin_unlock_bh(&zbud_budlists_spinlock);
pr_err("TESTING zbud_remotify_pages failed on page,"
" finished re-add\n");
goto out;
}
spin_unlock_bh(&zbud_budlists_spinlock);
preempt_enable();
}
next_buddied_zbpg:
preempt_disable(); /* enable in zbud_remotify_zbpg */
spin_lock_bh(&zbud_budlists_spinlock);
if (list_empty(&zbud_buddied_list))
goto unlock_out;
list_for_each_entry(zbpg, &zbud_buddied_list, bud_list) {
if (unlikely(!spin_trylock(&zbpg->lock)))
continue; /* next list_for_each_entry */
zcache_zbud_buddied_count--;
/* want budlists unlocked when doing zbpg remotify */
spin_unlock_bh(&zbud_budlists_spinlock);
ret = zbud_remotify_zbpg(zbpg);
/* preemption is re-enabled in zbud_remotify_zbpg */
if (ret == 0) {
if (--nr <= 0)
goto out;
goto next_buddied_zbpg;
}
/* if fail to remotify any page, quit */
pr_err("TESTING zbud_remotify_pages failed on BUDDIED page,"
" trying to re-add\n");
spin_lock_bh(&zbud_budlists_spinlock);
spin_lock(&zbpg->lock);
list_add_tail(&zbpg->bud_list, &zbud_buddied_list);
zcache_zbud_buddied_count++;
spin_unlock(&zbpg->lock);
spin_unlock_bh(&zbud_budlists_spinlock);
pr_err("TESTING zbud_remotify_pages failed on BUDDIED page,"
" finished re-add\n");
goto out;
}
unlock_out:
spin_unlock_bh(&zbud_budlists_spinlock);
preempt_enable();
out:
return;
}
/* the "flush list" asynchronously collects pages to remotely flush */
#define FLUSH_ENTIRE_OBJECT ((uint32_t)-1)
static void ramster_flnode_free(struct flushlist_node *,
struct tmem_pool *);
static void zcache_remote_flush_page(struct flushlist_node *flnode)
{
struct tmem_xhandle *xh;
int remotenode, ret;
preempt_disable();
xh = &flnode->xh;
remotenode = flnode->xh.client_id;
ret = ramster_remote_flush(xh, remotenode);
if (ret >= 0)
ramster_remote_pages_flushed++;
else
ramster_remote_page_flushes_failed++;
preempt_enable_no_resched();
ramster_flnode_free(flnode, NULL);
}
static void zcache_remote_flush_object(struct flushlist_node *flnode)
{
struct tmem_xhandle *xh;
int remotenode, ret;
preempt_disable();
xh = &flnode->xh;
remotenode = flnode->xh.client_id;
ret = ramster_remote_flush_object(xh, remotenode);
if (ret >= 0)
ramster_remote_objects_flushed++;
else
ramster_remote_object_flushes_failed++;
preempt_enable_no_resched();
ramster_flnode_free(flnode, NULL);
}
static void zcache_remote_eph_put(struct zbud_hdr *zbud)
{
/* FIXME */
}
static void zcache_remote_pers_put(struct zv_hdr *zv)
{
struct tmem_xhandle xh;
uint16_t size;
bool ephemeral;
int remotenode, ret = -1;
char *data;
struct tmem_pool *pool;
unsigned long flags;
unsigned char cksum;
char *p;
int i;
unsigned char *tmpmem = __get_cpu_var(zcache_remoteputmem);
ASSERT_SENTINEL(zv, ZVH);
BUG_ON(zv->client_id != LOCAL_CLIENT);
local_bh_disable();
xh.client_id = zv->client_id;
xh.pool_id = zv->pool_id;
xh.oid = zv->oid;
xh.index = zv->index;
size = xv_get_object_size(zv) - sizeof(*zv);
BUG_ON(size == 0 || size > zv_max_page_size);
data = (char *)zv + sizeof(*zv);
for (p = data, cksum = 0, i = 0; i < size; i++)
cksum += *p;
memcpy(tmpmem, data, size);
data = tmpmem;
pool = zcache_get_pool_by_id(zv->client_id, zv->pool_id);
ephemeral = is_ephemeral(pool);
zcache_put_pool(pool);
/* now OK to release lock set in caller */
spin_unlock(&zcache_rem_op_list_lock);
local_bh_enable();
preempt_disable();
ret = ramster_remote_put(&xh, data, size, ephemeral, &remotenode);
preempt_enable_no_resched();
if (ret != 0) {
/*
* This is some form of a memory leak... if the remote put
* fails, there will never be another attempt to remotify
* this page. But since we've dropped the zv pointer,
* the page may have been freed or the data replaced
* so we can't just "put it back" in the remote op list.
* Even if we could, not sure where to put it in the list
* because there may be flushes that must be strictly
* ordered vs the put. So leave this as a FIXME for now.
* But count them so we know if it becomes a problem.
*/
ramster_pers_pages_remote_failed++;
goto out;
} else
atomic_inc(&ramster_remote_pers_pages);
ramster_pers_pages_remoted++;
/*
* data was successfully remoted so change the local version to
* point to the remote node where it landed
*/
local_bh_disable();
pool = zcache_get_pool_by_id(LOCAL_CLIENT, xh.pool_id);
local_irq_save(flags);
(void)tmem_replace(pool, &xh.oid, xh.index,
pampd_make_remote(remotenode, size, cksum));
local_irq_restore(flags);
zcache_put_pool(pool);
local_bh_enable();
out:
return;
}
static void zcache_do_remotify_ops(int nr)
{
struct ramster_remotify_hdr *rem_op;
union remotify_list_node *u;
while (1) {
if (!nr)
goto out;
spin_lock(&zcache_rem_op_list_lock);
if (list_empty(&zcache_rem_op_list)) {
spin_unlock(&zcache_rem_op_list_lock);
goto out;
}
rem_op = list_first_entry(&zcache_rem_op_list,
struct ramster_remotify_hdr, list);
list_del_init(&rem_op->list);
if (rem_op->op != RAMSTER_REMOTIFY_PERS_PUT)
spin_unlock(&zcache_rem_op_list_lock);
u = (union remotify_list_node *)rem_op;
switch (rem_op->op) {
case RAMSTER_REMOTIFY_EPH_PUT:
BUG();
zcache_remote_eph_put((struct zbud_hdr *)rem_op);
break;
case RAMSTER_REMOTIFY_PERS_PUT:
zcache_remote_pers_put((struct zv_hdr *)rem_op);
break;
case RAMSTER_REMOTIFY_FLUSH_PAGE:
zcache_remote_flush_page((struct flushlist_node *)u);
break;
case RAMSTER_REMOTIFY_FLUSH_OBJ:
zcache_remote_flush_object((struct flushlist_node *)u);
break;
default:
BUG();
}
}
out:
return;
}
/*
* Communicate interface revision with userspace
*/
#include "cluster/ramster_nodemanager.h"
static unsigned long ramster_interface_revision = R2NM_API_VERSION;
/*
* For now, just push over a few pages every few seconds to
* ensure that it basically works
*/
static struct workqueue_struct *ramster_remotify_workqueue;
static void ramster_remotify_process(struct work_struct *work);
static DECLARE_DELAYED_WORK(ramster_remotify_worker,
ramster_remotify_process);
static void ramster_remotify_queue_delayed_work(unsigned long delay)
{
if (!queue_delayed_work(ramster_remotify_workqueue,
&ramster_remotify_worker, delay))
pr_err("ramster_remotify: bad workqueue\n");
}
static int use_frontswap;
static int use_cleancache;
static int ramster_remote_target_nodenum = -1;
static void ramster_remotify_process(struct work_struct *work)
{
static bool remotify_in_progress;
BUG_ON(irqs_disabled());
if (remotify_in_progress)
ramster_remotify_queue_delayed_work(HZ);
else if (ramster_remote_target_nodenum != -1) {
remotify_in_progress = true;
#ifdef CONFIG_CLEANCACHE
if (use_cleancache && ramster_eph_remotify_enable)
zbud_remotify_pages(5000); /* FIXME is this a good number? */
#endif
#ifdef CONFIG_FRONTSWAP
if (use_frontswap && ramster_pers_remotify_enable)
zcache_do_remotify_ops(500); /* FIXME is this a good number? */
#endif
remotify_in_progress = false;
ramster_remotify_queue_delayed_work(HZ);
}
}
static void ramster_remotify_init(void)
{
unsigned long n = 60UL;
ramster_remotify_workqueue =
create_singlethread_workqueue("ramster_remotify");
ramster_remotify_queue_delayed_work(n * HZ);
}
static void zbud_init(void)
{
int i;
INIT_LIST_HEAD(&zbud_buddied_list);
zcache_zbud_buddied_count = 0;
for (i = 0; i < NCHUNKS; i++) {
INIT_LIST_HEAD(&zbud_unbuddied[i].list);
zbud_unbuddied[i].count = 0;
}
}
#ifdef CONFIG_SYSFS
/*
* These sysfs routines show a nice distribution of how many zbpg's are
* currently (and have ever been placed) in each unbuddied list. It's fun
* to watch but can probably go away before final merge.
*/
static int zbud_show_unbuddied_list_counts(char *buf)
{
int i;
char *p = buf;
for (i = 0; i < NCHUNKS; i++)
p += sprintf(p, "%u ", zbud_unbuddied[i].count);
return p - buf;
}
static int zbud_show_cumul_chunk_counts(char *buf)
{
unsigned long i, chunks = 0, total_chunks = 0, sum_total_chunks = 0;
unsigned long total_chunks_lte_21 = 0, total_chunks_lte_32 = 0;
unsigned long total_chunks_lte_42 = 0;
char *p = buf;
for (i = 0; i < NCHUNKS; i++) {
p += sprintf(p, "%lu ", zbud_cumul_chunk_counts[i]);
chunks += zbud_cumul_chunk_counts[i];
total_chunks += zbud_cumul_chunk_counts[i];
sum_total_chunks += i * zbud_cumul_chunk_counts[i];
if (i == 21)
total_chunks_lte_21 = total_chunks;
if (i == 32)
total_chunks_lte_32 = total_chunks;
if (i == 42)
total_chunks_lte_42 = total_chunks;
}
p += sprintf(p, "<=21:%lu <=32:%lu <=42:%lu, mean:%lu\n",
total_chunks_lte_21, total_chunks_lte_32, total_chunks_lte_42,
chunks == 0 ? 0 : sum_total_chunks / chunks);
return p - buf;
}
#endif
/**********
* This "zv" PAM implementation combines the TLSF-based xvMalloc
* with lzo1x compression to maximize the amount of data that can
* be packed into a physical page.
*
* Zv represents a PAM page with the index and object (plus a "size" value
* necessary for decompression) immediately preceding the compressed data.
*/
/* rudimentary policy limits */
/* total number of persistent pages may not exceed this percentage */
static unsigned int zv_page_count_policy_percent = 75;
/*
* byte count defining poor compression; pages with greater zsize will be
* rejected
*/
static unsigned int zv_max_zsize = (PAGE_SIZE / 8) * 7;
/*
* byte count defining poor *mean* compression; pages with greater zsize
* will be rejected until sufficient better-compressed pages are accepted
* driving the mean below this threshold
*/
static unsigned int zv_max_mean_zsize = (PAGE_SIZE / 8) * 5;
static atomic_t zv_curr_dist_counts[NCHUNKS];
static atomic_t zv_cumul_dist_counts[NCHUNKS];
static struct zv_hdr *zv_create(struct zcache_client *cli, uint32_t pool_id,
struct tmem_oid *oid, uint32_t index,
void *cdata, unsigned clen)
{
struct page *page;
struct zv_hdr *zv = NULL;
uint32_t offset;
int alloc_size = clen + sizeof(struct zv_hdr);
int chunks = (alloc_size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT;
int ret;
BUG_ON(!irqs_disabled());
BUG_ON(chunks >= NCHUNKS);
ret = xv_malloc(cli->xvpool, clen + sizeof(struct zv_hdr),
&page, &offset, ZCACHE_GFP_MASK);
if (unlikely(ret))
goto out;
atomic_inc(&zv_curr_dist_counts[chunks]);
atomic_inc(&zv_cumul_dist_counts[chunks]);
zv = kmap_atomic(page) + offset;
zv->index = index;
zv->oid = *oid;
zv->pool_id = pool_id;
SET_SENTINEL(zv, ZVH);
INIT_LIST_HEAD(&zv->rem_op.list);
zv->client_id = get_client_id_from_client(cli);
zv->rem_op.op = RAMSTER_REMOTIFY_PERS_PUT;
if (zv->client_id == LOCAL_CLIENT) {
spin_lock(&zcache_rem_op_list_lock);
list_add_tail(&zv->rem_op.list, &zcache_rem_op_list);
spin_unlock(&zcache_rem_op_list_lock);
}
memcpy((char *)zv + sizeof(struct zv_hdr), cdata, clen);
kunmap_atomic(zv);
out:
return zv;
}
/* similar to zv_create, but just reserve space, no data yet */
static struct zv_hdr *zv_alloc(struct tmem_pool *pool,
struct tmem_oid *oid, uint32_t index,
unsigned clen)
{
struct zcache_client *cli = pool->client;
struct page *page;
struct zv_hdr *zv = NULL;
uint32_t offset;
int ret;
BUG_ON(!irqs_disabled());
BUG_ON(!is_local_client(pool->client));
ret = xv_malloc(cli->xvpool, clen + sizeof(struct zv_hdr),
&page, &offset, ZCACHE_GFP_MASK);
if (unlikely(ret))
goto out;
zv = kmap_atomic(page) + offset;
SET_SENTINEL(zv, ZVH);
INIT_LIST_HEAD(&zv->rem_op.list);
zv->client_id = LOCAL_CLIENT;
zv->rem_op.op = RAMSTER_INTRANSIT_PERS;
zv->index = index;
zv->oid = *oid;
zv->pool_id = pool->pool_id;
kunmap_atomic(zv);
out:
return zv;
}
static void zv_free(struct xv_pool *xvpool, struct zv_hdr *zv)
{
unsigned long flags;
struct page *page;
uint32_t offset;
uint16_t size = xv_get_object_size(zv);
int chunks = (size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT;
ASSERT_SENTINEL(zv, ZVH);
BUG_ON(chunks >= NCHUNKS);
atomic_dec(&zv_curr_dist_counts[chunks]);
size -= sizeof(*zv);
spin_lock(&zcache_rem_op_list_lock);
size = xv_get_object_size(zv) - sizeof(*zv);
BUG_ON(size == 0);
INVERT_SENTINEL(zv, ZVH);
if (!list_empty(&zv->rem_op.list))
list_del_init(&zv->rem_op.list);
spin_unlock(&zcache_rem_op_list_lock);
page = virt_to_page(zv);
offset = (unsigned long)zv & ~PAGE_MASK;
local_irq_save(flags);
xv_free(xvpool, page, offset);
local_irq_restore(flags);
}
static void zv_decompress(struct page *page, struct zv_hdr *zv)
{
size_t clen = PAGE_SIZE;
char *to_va;
unsigned size;
int ret;
ASSERT_SENTINEL(zv, ZVH);
size = xv_get_object_size(zv) - sizeof(*zv);
BUG_ON(size == 0);
to_va = kmap_atomic(page);
ret = lzo1x_decompress_safe((char *)zv + sizeof(*zv),
size, to_va, &clen);
kunmap_atomic(to_va);
BUG_ON(ret != LZO_E_OK);
BUG_ON(clen != PAGE_SIZE);
}
static void zv_copy_from_pampd(char *data, size_t *bufsize, struct zv_hdr *zv)
{
unsigned size;
ASSERT_SENTINEL(zv, ZVH);
size = xv_get_object_size(zv) - sizeof(*zv);
BUG_ON(size == 0 || size > zv_max_page_size);
BUG_ON(size > *bufsize);
memcpy(data, (char *)zv + sizeof(*zv), size);
*bufsize = size;
}
static void zv_copy_to_pampd(struct zv_hdr *zv, char *data, size_t size)
{
unsigned zv_size;
ASSERT_SENTINEL(zv, ZVH);
zv_size = xv_get_object_size(zv) - sizeof(*zv);
BUG_ON(zv_size != size);
BUG_ON(zv_size == 0 || zv_size > zv_max_page_size);
memcpy((char *)zv + sizeof(*zv), data, size);
}
#ifdef CONFIG_SYSFS
/*
* show a distribution of compression stats for zv pages.
*/
static int zv_curr_dist_counts_show(char *buf)
{
unsigned long i, n, chunks = 0, sum_total_chunks = 0;
char *p = buf;
for (i = 0; i < NCHUNKS; i++) {
n = atomic_read(&zv_curr_dist_counts[i]);
p += sprintf(p, "%lu ", n);
chunks += n;
sum_total_chunks += i * n;
}
p += sprintf(p, "mean:%lu\n",
chunks == 0 ? 0 : sum_total_chunks / chunks);
return p - buf;
}
static int zv_cumul_dist_counts_show(char *buf)
{
unsigned long i, n, chunks = 0, sum_total_chunks = 0;
char *p = buf;
for (i = 0; i < NCHUNKS; i++) {
n = atomic_read(&zv_cumul_dist_counts[i]);
p += sprintf(p, "%lu ", n);
chunks += n;
sum_total_chunks += i * n;
}
p += sprintf(p, "mean:%lu\n",
chunks == 0 ? 0 : sum_total_chunks / chunks);
return p - buf;
}
/*
* setting zv_max_zsize via sysfs causes all persistent (e.g. swap)
* pages that don't compress to less than this value (including metadata
* overhead) to be rejected. We don't allow the value to get too close
* to PAGE_SIZE.
*/
static ssize_t zv_max_zsize_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
{
return sprintf(buf, "%u\n", zv_max_zsize);
}
static ssize_t zv_max_zsize_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
unsigned long val;
int err;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
err = kstrtoul(buf, 10, &val);
if (err || (val == 0) || (val > (PAGE_SIZE / 8) * 7))
return -EINVAL;
zv_max_zsize = val;
return count;
}
/*
* setting zv_max_mean_zsize via sysfs causes all persistent (e.g. swap)
* pages that don't compress to less than this value (including metadata
* overhead) to be rejected UNLESS the mean compression is also smaller
* than this value. In other words, we are load-balancing-by-zsize the
* accepted pages. Again, we don't allow the value to get too close
* to PAGE_SIZE.
*/
static ssize_t zv_max_mean_zsize_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
{
return sprintf(buf, "%u\n", zv_max_mean_zsize);
}
static ssize_t zv_max_mean_zsize_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
unsigned long val;
int err;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
err = kstrtoul(buf, 10, &val);
if (err || (val == 0) || (val > (PAGE_SIZE / 8) * 7))
return -EINVAL;
zv_max_mean_zsize = val;
return count;
}
/*
* setting zv_page_count_policy_percent via sysfs sets an upper bound of
* persistent (e.g. swap) pages that will be retained according to:
* (zv_page_count_policy_percent * totalram_pages) / 100)
* when that limit is reached, further puts will be rejected (until
* some pages have been flushed). Note that, due to compression,
* this number may exceed 100; it defaults to 75 and we set an
* arbitrary limit of 150. A poor choice will almost certainly result
* in OOM's, so this value should only be changed prudently.
*/
static ssize_t zv_page_count_policy_percent_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
{
return sprintf(buf, "%u\n", zv_page_count_policy_percent);
}
static ssize_t zv_page_count_policy_percent_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
unsigned long val;
int err;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
err = kstrtoul(buf, 10, &val);
if (err || (val == 0) || (val > 150))
return -EINVAL;
zv_page_count_policy_percent = val;
return count;
}
static struct kobj_attribute zcache_zv_max_zsize_attr = {
.attr = { .name = "zv_max_zsize", .mode = 0644 },
.show = zv_max_zsize_show,
.store = zv_max_zsize_store,
};
static struct kobj_attribute zcache_zv_max_mean_zsize_attr = {
.attr = { .name = "zv_max_mean_zsize", .mode = 0644 },
.show = zv_max_mean_zsize_show,
.store = zv_max_mean_zsize_store,
};
static struct kobj_attribute zcache_zv_page_count_policy_percent_attr = {
.attr = { .name = "zv_page_count_policy_percent",
.mode = 0644 },
.show = zv_page_count_policy_percent_show,
.store = zv_page_count_policy_percent_store,
};
#endif
/*
* zcache core code starts here
*/
/* useful stats not collected by cleancache or frontswap */
static unsigned long zcache_flush_total;
static unsigned long zcache_flush_found;
static unsigned long zcache_flobj_total;
static unsigned long zcache_flobj_found;
static unsigned long zcache_failed_eph_puts;
static unsigned long zcache_nonactive_puts;
static unsigned long zcache_failed_pers_puts;
/*
* Tmem operations assume the poolid implies the invoking client.
* Zcache only has one client (the kernel itself): LOCAL_CLIENT.
* RAMster has each client numbered by cluster node, and a KVM version
* of zcache would have one client per guest and each client might
* have a poolid==N.
*/
static struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id, uint16_t poolid)
{
struct tmem_pool *pool = NULL;
struct zcache_client *cli = NULL;
if (cli_id == LOCAL_CLIENT)
cli = &zcache_host;
else {
if (cli_id >= MAX_CLIENTS)
goto out;
cli = &zcache_clients[cli_id];
if (cli == NULL)
goto out;
atomic_inc(&cli->refcount);
}
if (poolid < MAX_POOLS_PER_CLIENT) {
pool = cli->tmem_pools[poolid];
if (pool != NULL)
atomic_inc(&pool->refcount);
}
out:
return pool;
}
static void zcache_put_pool(struct tmem_pool *pool)
{
struct zcache_client *cli = NULL;
if (pool == NULL)
BUG();
cli = pool->client;
atomic_dec(&pool->refcount);
atomic_dec(&cli->refcount);
}
int zcache_new_client(uint16_t cli_id)
{
struct zcache_client *cli = NULL;
int ret = -1;
if (cli_id == LOCAL_CLIENT)
cli = &zcache_host;
else if ((unsigned int)cli_id < MAX_CLIENTS)
cli = &zcache_clients[cli_id];
if (cli == NULL)
goto out;
if (cli->allocated)
goto out;
cli->allocated = 1;
#ifdef CONFIG_FRONTSWAP
cli->xvpool = xv_create_pool();
if (cli->xvpool == NULL)
goto out;
#endif
ret = 0;
out:
return ret;
}
/* counters for debugging */
static unsigned long zcache_failed_get_free_pages;
static unsigned long zcache_failed_alloc;
static unsigned long zcache_put_to_flush;
/*
* for now, used named slabs so can easily track usage; later can
* either just use kmalloc, or perhaps add a slab-like allocator
* to more carefully manage total memory utilization
*/
static struct kmem_cache *zcache_objnode_cache;
static struct kmem_cache *zcache_obj_cache;
static struct kmem_cache *ramster_flnode_cache;
static atomic_t zcache_curr_obj_count = ATOMIC_INIT(0);
static unsigned long zcache_curr_obj_count_max;
static atomic_t zcache_curr_objnode_count = ATOMIC_INIT(0);
static unsigned long zcache_curr_objnode_count_max;
/*
* to avoid memory allocation recursion (e.g. due to direct reclaim), we
* preload all necessary data structures so the hostops callbacks never
* actually do a malloc
*/
struct zcache_preload {
void *page;
struct tmem_obj *obj;
int nr;
struct tmem_objnode *objnodes[OBJNODE_TREE_MAX_PATH];
struct flushlist_node *flnode;
};
static DEFINE_PER_CPU(struct zcache_preload, zcache_preloads) = { 0, };
static int zcache_do_preload(struct tmem_pool *pool)
{
struct zcache_preload *kp;
struct tmem_objnode *objnode;
struct tmem_obj *obj;
struct flushlist_node *flnode;
void *page;
int ret = -ENOMEM;
if (unlikely(zcache_objnode_cache == NULL))
goto out;
if (unlikely(zcache_obj_cache == NULL))
goto out;
preempt_disable();
kp = &__get_cpu_var(zcache_preloads);
while (kp->nr < ARRAY_SIZE(kp->objnodes)) {
preempt_enable_no_resched();
objnode = kmem_cache_alloc(zcache_objnode_cache,
ZCACHE_GFP_MASK);
if (unlikely(objnode == NULL)) {
zcache_failed_alloc++;
goto out;
}
preempt_disable();
kp = &__get_cpu_var(zcache_preloads);
if (kp->nr < ARRAY_SIZE(kp->objnodes))
kp->objnodes[kp->nr++] = objnode;
else
kmem_cache_free(zcache_objnode_cache, objnode);
}
preempt_enable_no_resched();
obj = kmem_cache_alloc(zcache_obj_cache, ZCACHE_GFP_MASK);
if (unlikely(obj == NULL)) {
zcache_failed_alloc++;
goto out;
}
flnode = kmem_cache_alloc(ramster_flnode_cache, ZCACHE_GFP_MASK);
if (unlikely(flnode == NULL)) {
zcache_failed_alloc++;
goto out;
}
if (is_ephemeral(pool)) {
page = (void *)__get_free_page(ZCACHE_GFP_MASK);
if (unlikely(page == NULL)) {
zcache_failed_get_free_pages++;
kmem_cache_free(zcache_obj_cache, obj);
kmem_cache_free(ramster_flnode_cache, flnode);
goto out;
}
}
preempt_disable();
kp = &__get_cpu_var(zcache_preloads);
if (kp->obj == NULL)
kp->obj = obj;
else
kmem_cache_free(zcache_obj_cache, obj);
if (kp->flnode == NULL)
kp->flnode = flnode;
else
kmem_cache_free(ramster_flnode_cache, flnode);
if (is_ephemeral(pool)) {
if (kp->page == NULL)
kp->page = page;
else
free_page((unsigned long)page);
}
ret = 0;
out:
return ret;
}
static int ramster_do_preload_flnode_only(struct tmem_pool *pool)
{
struct zcache_preload *kp;
struct flushlist_node *flnode;
int ret = -ENOMEM;
BUG_ON(!irqs_disabled());
if (unlikely(ramster_flnode_cache == NULL))
BUG();
kp = &__get_cpu_var(zcache_preloads);
flnode = kmem_cache_alloc(ramster_flnode_cache, GFP_ATOMIC);
if (unlikely(flnode == NULL) && kp->flnode == NULL)
BUG(); /* FIXME handle more gracefully, but how??? */
else if (kp->flnode == NULL)
kp->flnode = flnode;
else
kmem_cache_free(ramster_flnode_cache, flnode);
return ret;
}
static void *zcache_get_free_page(void)
{
struct zcache_preload *kp;
void *page;
kp = &__get_cpu_var(zcache_preloads);
page = kp->page;
BUG_ON(page == NULL);
kp->page = NULL;
return page;
}
static void zcache_free_page(void *p)
{
free_page((unsigned long)p);
}
/*
* zcache implementation for tmem host ops
*/
static struct tmem_objnode *zcache_objnode_alloc(struct tmem_pool *pool)
{
struct tmem_objnode *objnode = NULL;
unsigned long count;
struct zcache_preload *kp;
kp = &__get_cpu_var(zcache_preloads);
if (kp->nr <= 0)
goto out;
objnode = kp->objnodes[kp->nr - 1];
BUG_ON(objnode == NULL);
kp->objnodes[kp->nr - 1] = NULL;
kp->nr--;
count = atomic_inc_return(&zcache_curr_objnode_count);
if (count > zcache_curr_objnode_count_max)
zcache_curr_objnode_count_max = count;
out:
return objnode;
}
static void zcache_objnode_free(struct tmem_objnode *objnode,
struct tmem_pool *pool)
{
atomic_dec(&zcache_curr_objnode_count);
BUG_ON(atomic_read(&zcache_curr_objnode_count) < 0);
kmem_cache_free(zcache_objnode_cache, objnode);
}
static struct tmem_obj *zcache_obj_alloc(struct tmem_pool *pool)
{
struct tmem_obj *obj = NULL;
unsigned long count;
struct zcache_preload *kp;
kp = &__get_cpu_var(zcache_preloads);
obj = kp->obj;
BUG_ON(obj == NULL);
kp->obj = NULL;
count = atomic_inc_return(&zcache_curr_obj_count);
if (count > zcache_curr_obj_count_max)
zcache_curr_obj_count_max = count;
return obj;
}
static void zcache_obj_free(struct tmem_obj *obj, struct tmem_pool *pool)
{
atomic_dec(&zcache_curr_obj_count);
BUG_ON(atomic_read(&zcache_curr_obj_count) < 0);
kmem_cache_free(zcache_obj_cache, obj);
}
static struct flushlist_node *ramster_flnode_alloc(struct tmem_pool *pool)
{
struct flushlist_node *flnode = NULL;
struct zcache_preload *kp;
int count;
kp = &__get_cpu_var(zcache_preloads);
flnode = kp->flnode;
BUG_ON(flnode == NULL);
kp->flnode = NULL;
count = atomic_inc_return(&ramster_curr_flnode_count);
if (count > ramster_curr_flnode_count_max)
ramster_curr_flnode_count_max = count;
return flnode;
}
static void ramster_flnode_free(struct flushlist_node *flnode,
struct tmem_pool *pool)
{
atomic_dec(&ramster_curr_flnode_count);
BUG_ON(atomic_read(&ramster_curr_flnode_count) < 0);
kmem_cache_free(ramster_flnode_cache, flnode);
}
static struct tmem_hostops zcache_hostops = {
.obj_alloc = zcache_obj_alloc,
.obj_free = zcache_obj_free,
.objnode_alloc = zcache_objnode_alloc,
.objnode_free = zcache_objnode_free,
};
/*
* zcache implementations for PAM page descriptor ops
*/
static inline void dec_and_check(atomic_t *pvar)
{
atomic_dec(pvar);
/* later when all accounting is fixed, make this a BUG */
WARN_ON_ONCE(atomic_read(pvar) < 0);
}
static atomic_t zcache_curr_eph_pampd_count = ATOMIC_INIT(0);
static unsigned long zcache_curr_eph_pampd_count_max;
static atomic_t zcache_curr_pers_pampd_count = ATOMIC_INIT(0);
static unsigned long zcache_curr_pers_pampd_count_max;
/* forward reference */
static int zcache_compress(struct page *from, void **out_va, size_t *out_len);
static int zcache_pampd_eph_create(char *data, size_t size, bool raw,
struct tmem_pool *pool, struct tmem_oid *oid,
uint32_t index, void **pampd)
{
int ret = -1;
void *cdata = data;
size_t clen = size;
struct zcache_client *cli = pool->client;
uint16_t client_id = get_client_id_from_client(cli);
struct page *page = NULL;
unsigned long count;
if (!raw) {
page = virt_to_page(data);
ret = zcache_compress(page, &cdata, &clen);
if (ret == 0)
goto out;
if (clen == 0 || clen > zbud_max_buddy_size()) {
zcache_compress_poor++;
goto out;
}
}
*pampd = (void *)zbud_create(client_id, pool->pool_id, oid,
index, page, cdata, clen);
if (*pampd == NULL) {
ret = -ENOMEM;
goto out;
}
ret = 0;
count = atomic_inc_return(&zcache_curr_eph_pampd_count);
if (count > zcache_curr_eph_pampd_count_max)
zcache_curr_eph_pampd_count_max = count;
if (client_id != LOCAL_CLIENT) {
count = atomic_inc_return(&ramster_foreign_eph_pampd_count);
if (count > ramster_foreign_eph_pampd_count_max)
ramster_foreign_eph_pampd_count_max = count;
}
out:
return ret;
}
static int zcache_pampd_pers_create(char *data, size_t size, bool raw,
struct tmem_pool *pool, struct tmem_oid *oid,
uint32_t index, void **pampd)
{
int ret = -1;
void *cdata = data;
size_t clen = size;
struct zcache_client *cli = pool->client;
struct page *page;
unsigned long count;
unsigned long zv_mean_zsize;
struct zv_hdr *zv;
long curr_pers_pampd_count;
u64 total_zsize;
#ifdef RAMSTER_TESTING
static bool pampd_neg_warned;
#endif
curr_pers_pampd_count = atomic_read(&zcache_curr_pers_pampd_count) -
atomic_read(&ramster_remote_pers_pages);
#ifdef RAMSTER_TESTING
/* should always be positive, but warn if accounting is off */
if (!pampd_neg_warned) {
pr_warn("ramster: bad accounting for curr_pers_pampd_count\n");
pampd_neg_warned = true;
}
#endif
if (curr_pers_pampd_count >
(zv_page_count_policy_percent * totalram_pages) / 100) {
zcache_policy_percent_exceeded++;
goto out;
}
if (raw)
goto ok_to_create;
page = virt_to_page(data);
if (zcache_compress(page, &cdata, &clen) == 0)
goto out;
/* reject if compression is too poor */
if (clen > zv_max_zsize) {
zcache_compress_poor++;
goto out;
}
/* reject if mean compression is too poor */
if ((clen > zv_max_mean_zsize) && (curr_pers_pampd_count > 0)) {
total_zsize = xv_get_total_size_bytes(cli->xvpool);
zv_mean_zsize = div_u64(total_zsize, curr_pers_pampd_count);
if (zv_mean_zsize > zv_max_mean_zsize) {
zcache_mean_compress_poor++;
goto out;
}
}
ok_to_create:
*pampd = (void *)zv_create(cli, pool->pool_id, oid, index, cdata, clen);
if (*pampd == NULL) {
ret = -ENOMEM;
goto out;
}
ret = 0;
count = atomic_inc_return(&zcache_curr_pers_pampd_count);
if (count > zcache_curr_pers_pampd_count_max)
zcache_curr_pers_pampd_count_max = count;
if (is_local_client(cli))
goto out;
zv = *(struct zv_hdr **)pampd;
count = atomic_inc_return(&ramster_foreign_pers_pampd_count);
if (count > ramster_foreign_pers_pampd_count_max)
ramster_foreign_pers_pampd_count_max = count;
out:
return ret;
}
static void *zcache_pampd_create(char *data, size_t size, bool raw, int eph,
struct tmem_pool *pool, struct tmem_oid *oid,
uint32_t index)
{
void *pampd = NULL;
int ret;
bool ephemeral;
BUG_ON(preemptible());
ephemeral = (eph == 1) || ((eph == 0) && is_ephemeral(pool));
if (ephemeral)
ret = zcache_pampd_eph_create(data, size, raw, pool,
oid, index, &pampd);
else
ret = zcache_pampd_pers_create(data, size, raw, pool,
oid, index, &pampd);
/* FIXME add some counters here for failed creates? */
return pampd;
}
/*
* fill the pageframe corresponding to the struct page with the data
* from the passed pampd
*/
static int zcache_pampd_get_data(char *data, size_t *bufsize, bool raw,
void *pampd, struct tmem_pool *pool,
struct tmem_oid *oid, uint32_t index)
{
int ret = 0;
BUG_ON(preemptible());
BUG_ON(is_ephemeral(pool)); /* Fix later for shared pools? */
BUG_ON(pampd_is_remote(pampd));
if (raw)
zv_copy_from_pampd(data, bufsize, pampd);
else
zv_decompress(virt_to_page(data), pampd);
return ret;
}
static int zcache_pampd_get_data_and_free(char *data, size_t *bufsize, bool raw,
void *pampd, struct tmem_pool *pool,
struct tmem_oid *oid, uint32_t index)
{
int ret = 0;
unsigned long flags;
struct zcache_client *cli = pool->client;
BUG_ON(preemptible());
BUG_ON(pampd_is_remote(pampd));
if (is_ephemeral(pool)) {
local_irq_save(flags);
if (raw)
zbud_copy_from_pampd(data, bufsize, pampd);
else
ret = zbud_decompress(virt_to_page(data), pampd);
zbud_free_and_delist((struct zbud_hdr *)pampd);
local_irq_restore(flags);
if (!is_local_client(cli))
dec_and_check(&ramster_foreign_eph_pampd_count);
dec_and_check(&zcache_curr_eph_pampd_count);
} else {
if (is_local_client(cli))
BUG();
if (raw)
zv_copy_from_pampd(data, bufsize, pampd);
else
zv_decompress(virt_to_page(data), pampd);
zv_free(cli->xvpool, pampd);
if (!is_local_client(cli))
dec_and_check(&ramster_foreign_pers_pampd_count);
dec_and_check(&zcache_curr_pers_pampd_count);
ret = 0;
}
return ret;
}
static bool zcache_pampd_is_remote(void *pampd)
{
return pampd_is_remote(pampd);
}
/*
* free the pampd and remove it from any zcache lists
* pampd must no longer be pointed to from any tmem data structures!
*/
static void zcache_pampd_free(void *pampd, struct tmem_pool *pool,
struct tmem_oid *oid, uint32_t index, bool acct)
{
struct zcache_client *cli = pool->client;
bool eph = is_ephemeral(pool);
struct zv_hdr *zv;
BUG_ON(preemptible());
if (pampd_is_remote(pampd)) {
WARN_ON(acct == false);
if (oid == NULL) {
/*
* a NULL oid means to ignore this pampd free
* as the remote freeing will be handled elsewhere
*/
} else if (eph) {
/* FIXME remote flush optional but probably good idea */
/* FIXME get these working properly again */
dec_and_check(&zcache_curr_eph_pampd_count);
} else if (pampd_is_intransit(pampd)) {
/* did a pers remote get_and_free, so just free local */
pampd = pampd_mask_intransit_and_remote(pampd);
goto local_pers;
} else {
struct flushlist_node *flnode =
ramster_flnode_alloc(pool);
flnode->xh.client_id = pampd_remote_node(pampd);
flnode->xh.pool_id = pool->pool_id;
flnode->xh.oid = *oid;
flnode->xh.index = index;
flnode->rem_op.op = RAMSTER_REMOTIFY_FLUSH_PAGE;
spin_lock(&zcache_rem_op_list_lock);
list_add(&flnode->rem_op.list, &zcache_rem_op_list);
spin_unlock(&zcache_rem_op_list_lock);
dec_and_check(&zcache_curr_pers_pampd_count);
dec_and_check(&ramster_remote_pers_pages);
}
} else if (eph) {
zbud_free_and_delist((struct zbud_hdr *)pampd);
if (!is_local_client(pool->client))
dec_and_check(&ramster_foreign_eph_pampd_count);
if (acct)
/* FIXME get these working properly again */
dec_and_check(&zcache_curr_eph_pampd_count);
} else {
local_pers:
zv = (struct zv_hdr *)pampd;
if (!is_local_client(pool->client))
dec_and_check(&ramster_foreign_pers_pampd_count);
zv_free(cli->xvpool, zv);
if (acct)
/* FIXME get these working properly again */
dec_and_check(&zcache_curr_pers_pampd_count);
}
}
static void zcache_pampd_free_obj(struct tmem_pool *pool,
struct tmem_obj *obj)
{
struct flushlist_node *flnode;
BUG_ON(preemptible());
if (obj->extra == NULL)
return;
BUG_ON(!pampd_is_remote(obj->extra));
flnode = ramster_flnode_alloc(pool);
flnode->xh.client_id = pampd_remote_node(obj->extra);
flnode->xh.pool_id = pool->pool_id;
flnode->xh.oid = obj->oid;
flnode->xh.index = FLUSH_ENTIRE_OBJECT;
flnode->rem_op.op = RAMSTER_REMOTIFY_FLUSH_OBJ;
spin_lock(&zcache_rem_op_list_lock);
list_add(&flnode->rem_op.list, &zcache_rem_op_list);
spin_unlock(&zcache_rem_op_list_lock);
}
void zcache_pampd_new_obj(struct tmem_obj *obj)
{
obj->extra = NULL;
}
int zcache_pampd_replace_in_obj(void *new_pampd, struct tmem_obj *obj)
{
int ret = -1;
if (new_pampd != NULL) {
if (obj->extra == NULL)
obj->extra = new_pampd;
/* enforce that all remote pages in an object reside
* in the same node! */
else if (pampd_remote_node(new_pampd) !=
pampd_remote_node((void *)(obj->extra)))
BUG();
ret = 0;
}
return ret;
}
/*
* Called by the message handler after a (still compressed) page has been
* fetched from the remote machine in response to an "is_remote" tmem_get
* or persistent tmem_localify. For a tmem_get, "extra" is the address of
* the page that is to be filled to successfully resolve the tmem_get; for
* a (persistent) tmem_localify, "extra" is NULL (as the data is placed only
* in the local zcache). "data" points to "size" bytes of (compressed) data
* passed in the message. In the case of a persistent remote get, if
* pre-allocation was successful (see zcache_repatriate_preload), the page
* is placed into both local zcache and at "extra".
*/
int zcache_localify(int pool_id, struct tmem_oid *oidp,
uint32_t index, char *data, size_t size,
void *extra)
{
int ret = -ENOENT;
unsigned long flags;
struct tmem_pool *pool;
bool ephemeral, delete = false;
size_t clen = PAGE_SIZE;
void *pampd, *saved_hb;
struct tmem_obj *obj;
pool = zcache_get_pool_by_id(LOCAL_CLIENT, pool_id);
if (unlikely(pool == NULL))
/* pool doesn't exist anymore */
goto out;
ephemeral = is_ephemeral(pool);
local_irq_save(flags); /* FIXME: maybe only disable softirqs? */
pampd = tmem_localify_get_pampd(pool, oidp, index, &obj, &saved_hb);
if (pampd == NULL) {
/* hmmm... must have been a flush while waiting */
#ifdef RAMSTER_TESTING
pr_err("UNTESTED pampd==NULL in zcache_localify\n");
#endif
if (ephemeral)
ramster_remote_eph_pages_unsucc_get++;
else
ramster_remote_pers_pages_unsucc_get++;
obj = NULL;
goto finish;
} else if (unlikely(!pampd_is_remote(pampd))) {
/* hmmm... must have been a dup put while waiting */
#ifdef RAMSTER_TESTING
pr_err("UNTESTED dup while waiting in zcache_localify\n");
#endif
if (ephemeral)
ramster_remote_eph_pages_unsucc_get++;
else
ramster_remote_pers_pages_unsucc_get++;
obj = NULL;
pampd = NULL;
ret = -EEXIST;
goto finish;
} else if (size == 0) {
/* no remote data, delete the local is_remote pampd */
pampd = NULL;
if (ephemeral)
ramster_remote_eph_pages_unsucc_get++;
else
BUG();
delete = true;
goto finish;
}
if (!ephemeral && pampd_is_intransit(pampd)) {
/* localify to zcache */
pampd = pampd_mask_intransit_and_remote(pampd);
zv_copy_to_pampd(pampd, data, size);
} else {
pampd = NULL;
obj = NULL;
}
if (extra != NULL) {
/* decompress direct-to-memory to complete remotify */
ret = lzo1x_decompress_safe((char *)data, size,
(char *)extra, &clen);
BUG_ON(ret != LZO_E_OK);
BUG_ON(clen != PAGE_SIZE);
}
if (ephemeral)
ramster_remote_eph_pages_succ_get++;
else
ramster_remote_pers_pages_succ_get++;
ret = 0;
finish:
tmem_localify_finish(obj, index, pampd, saved_hb, delete);
zcache_put_pool(pool);
local_irq_restore(flags);
out:
return ret;
}
/*
* Called on a remote persistent tmem_get to attempt to preallocate
* local storage for the data contained in the remote persistent page.
* If successfully preallocated, returns the pampd, marked as remote and
* in_transit. Else returns NULL. Note that the appropriate tmem data
* structure must be locked.
*/
static void *zcache_pampd_repatriate_preload(void *pampd,
struct tmem_pool *pool,
struct tmem_oid *oid,
uint32_t index,
bool *intransit)
{
int clen = pampd_remote_size(pampd);
void *ret_pampd = NULL;
unsigned long flags;
if (!pampd_is_remote(pampd))
BUG();
if (is_ephemeral(pool))
BUG();
if (pampd_is_intransit(pampd)) {
/*
* to avoid multiple allocations (and maybe a memory leak)
* don't preallocate if already in the process of being
* repatriated
*/
*intransit = true;
goto out;
}
*intransit = false;
local_irq_save(flags);
ret_pampd = (void *)zv_alloc(pool, oid, index, clen);
if (ret_pampd != NULL) {
/*
* a pampd is marked intransit if it is remote and space has
* been allocated for it locally (note, only happens for
* persistent pages, in which case the remote copy is freed)
*/
ret_pampd = pampd_mark_intransit(ret_pampd);
dec_and_check(&ramster_remote_pers_pages);
} else
ramster_pers_pages_remote_nomem++;
local_irq_restore(flags);
out:
return ret_pampd;
}
/*
* Called on a remote tmem_get to invoke a message to fetch the page.
* Might sleep so no tmem locks can be held. "extra" is passed
* all the way through the round-trip messaging to zcache_localify.
*/
static int zcache_pampd_repatriate(void *fake_pampd, void *real_pampd,
struct tmem_pool *pool,
struct tmem_oid *oid, uint32_t index,
bool free, void *extra)
{
struct tmem_xhandle xh;
int ret;
if (pampd_is_intransit(real_pampd))
/* have local space pre-reserved, so free remote copy */
free = true;
xh = tmem_xhandle_fill(LOCAL_CLIENT, pool, oid, index);
/* unreliable request/response for now */
ret = ramster_remote_async_get(&xh, free,
pampd_remote_node(fake_pampd),
pampd_remote_size(fake_pampd),
pampd_remote_cksum(fake_pampd),
extra);
#ifdef RAMSTER_TESTING
if (ret != 0 && ret != -ENOENT)
pr_err("TESTING zcache_pampd_repatriate returns, ret=%d\n",
ret);
#endif
return ret;
}
static struct tmem_pamops zcache_pamops = {
.create = zcache_pampd_create,
.get_data = zcache_pampd_get_data,
.free = zcache_pampd_free,
.get_data_and_free = zcache_pampd_get_data_and_free,
.free_obj = zcache_pampd_free_obj,
.is_remote = zcache_pampd_is_remote,
.repatriate_preload = zcache_pampd_repatriate_preload,
.repatriate = zcache_pampd_repatriate,
.new_obj = zcache_pampd_new_obj,
.replace_in_obj = zcache_pampd_replace_in_obj,
};
/*
* zcache compression/decompression and related per-cpu stuff
*/
#define LZO_WORKMEM_BYTES LZO1X_1_MEM_COMPRESS
#define LZO_DSTMEM_PAGE_ORDER 1
static DEFINE_PER_CPU(unsigned char *, zcache_workmem);
static DEFINE_PER_CPU(unsigned char *, zcache_dstmem);
static int zcache_compress(struct page *from, void **out_va, size_t *out_len)
{
int ret = 0;
unsigned char *dmem = __get_cpu_var(zcache_dstmem);
unsigned char *wmem = __get_cpu_var(zcache_workmem);
char *from_va;
BUG_ON(!irqs_disabled());
if (unlikely(dmem == NULL || wmem == NULL))
goto out; /* no buffer, so can't compress */
from_va = kmap_atomic(from);
mb();
ret = lzo1x_1_compress(from_va, PAGE_SIZE, dmem, out_len, wmem);
BUG_ON(ret != LZO_E_OK);
*out_va = dmem;
kunmap_atomic(from_va);
ret = 1;
out:
return ret;
}
static int zcache_cpu_notifier(struct notifier_block *nb,
unsigned long action, void *pcpu)
{
int cpu = (long)pcpu;
struct zcache_preload *kp;
switch (action) {
case CPU_UP_PREPARE:
per_cpu(zcache_dstmem, cpu) = (void *)__get_free_pages(
GFP_KERNEL | __GFP_REPEAT,
LZO_DSTMEM_PAGE_ORDER),
per_cpu(zcache_workmem, cpu) =
kzalloc(LZO1X_MEM_COMPRESS,
GFP_KERNEL | __GFP_REPEAT);
per_cpu(zcache_remoteputmem, cpu) =
kzalloc(PAGE_SIZE, GFP_KERNEL | __GFP_REPEAT);
break;
case CPU_DEAD:
case CPU_UP_CANCELED:
kfree(per_cpu(zcache_remoteputmem, cpu));
per_cpu(zcache_remoteputmem, cpu) = NULL;
free_pages((unsigned long)per_cpu(zcache_dstmem, cpu),
LZO_DSTMEM_PAGE_ORDER);
per_cpu(zcache_dstmem, cpu) = NULL;
kfree(per_cpu(zcache_workmem, cpu));
per_cpu(zcache_workmem, cpu) = NULL;
kp = &per_cpu(zcache_preloads, cpu);
while (kp->nr) {
kmem_cache_free(zcache_objnode_cache,
kp->objnodes[kp->nr - 1]);
kp->objnodes[kp->nr - 1] = NULL;
kp->nr--;
}
if (kp->obj) {
kmem_cache_free(zcache_obj_cache, kp->obj);
kp->obj = NULL;
}
if (kp->flnode) {
kmem_cache_free(ramster_flnode_cache, kp->flnode);
kp->flnode = NULL;
}
if (kp->page) {
free_page((unsigned long)kp->page);
kp->page = NULL;
}
break;
default:
break;
}
return NOTIFY_OK;
}
static struct notifier_block zcache_cpu_notifier_block = {
.notifier_call = zcache_cpu_notifier
};
#ifdef CONFIG_SYSFS
#define ZCACHE_SYSFS_RO(_name) \
static ssize_t zcache_##_name##_show(struct kobject *kobj, \
struct kobj_attribute *attr, char *buf) \
{ \
return sprintf(buf, "%lu\n", zcache_##_name); \
} \
static struct kobj_attribute zcache_##_name##_attr = { \
.attr = { .name = __stringify(_name), .mode = 0444 }, \
.show = zcache_##_name##_show, \
}
#define ZCACHE_SYSFS_RO_ATOMIC(_name) \
static ssize_t zcache_##_name##_show(struct kobject *kobj, \
struct kobj_attribute *attr, char *buf) \
{ \
return sprintf(buf, "%d\n", atomic_read(&zcache_##_name)); \
} \
static struct kobj_attribute zcache_##_name##_attr = { \
.attr = { .name = __stringify(_name), .mode = 0444 }, \
.show = zcache_##_name##_show, \
}
#define ZCACHE_SYSFS_RO_CUSTOM(_name, _func) \
static ssize_t zcache_##_name##_show(struct kobject *kobj, \
struct kobj_attribute *attr, char *buf) \
{ \
return _func(buf); \
} \
static struct kobj_attribute zcache_##_name##_attr = { \
.attr = { .name = __stringify(_name), .mode = 0444 }, \
.show = zcache_##_name##_show, \
}
ZCACHE_SYSFS_RO(curr_obj_count_max);
ZCACHE_SYSFS_RO(curr_objnode_count_max);
ZCACHE_SYSFS_RO(flush_total);
ZCACHE_SYSFS_RO(flush_found);
ZCACHE_SYSFS_RO(flobj_total);
ZCACHE_SYSFS_RO(flobj_found);
ZCACHE_SYSFS_RO(failed_eph_puts);
ZCACHE_SYSFS_RO(nonactive_puts);
ZCACHE_SYSFS_RO(failed_pers_puts);
ZCACHE_SYSFS_RO(zbud_curr_zbytes);
ZCACHE_SYSFS_RO(zbud_cumul_zpages);
ZCACHE_SYSFS_RO(zbud_cumul_zbytes);
ZCACHE_SYSFS_RO(zbud_buddied_count);
ZCACHE_SYSFS_RO(evicted_raw_pages);
ZCACHE_SYSFS_RO(evicted_unbuddied_pages);
ZCACHE_SYSFS_RO(evicted_buddied_pages);
ZCACHE_SYSFS_RO(failed_get_free_pages);
ZCACHE_SYSFS_RO(failed_alloc);
ZCACHE_SYSFS_RO(put_to_flush);
ZCACHE_SYSFS_RO(compress_poor);
ZCACHE_SYSFS_RO(mean_compress_poor);
ZCACHE_SYSFS_RO(policy_percent_exceeded);
ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_raw_pages);
ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_zpages);
ZCACHE_SYSFS_RO_ATOMIC(curr_obj_count);
ZCACHE_SYSFS_RO_ATOMIC(curr_objnode_count);
ZCACHE_SYSFS_RO_CUSTOM(zbud_unbuddied_list_counts,
zbud_show_unbuddied_list_counts);
ZCACHE_SYSFS_RO_CUSTOM(zbud_cumul_chunk_counts,
zbud_show_cumul_chunk_counts);
ZCACHE_SYSFS_RO_CUSTOM(zv_curr_dist_counts,
zv_curr_dist_counts_show);
ZCACHE_SYSFS_RO_CUSTOM(zv_cumul_dist_counts,
zv_cumul_dist_counts_show);
static struct attribute *zcache_attrs[] = {
&zcache_curr_obj_count_attr.attr,
&zcache_curr_obj_count_max_attr.attr,
&zcache_curr_objnode_count_attr.attr,
&zcache_curr_objnode_count_max_attr.attr,
&zcache_flush_total_attr.attr,
&zcache_flobj_total_attr.attr,
&zcache_flush_found_attr.attr,
&zcache_flobj_found_attr.attr,
&zcache_failed_eph_puts_attr.attr,
&zcache_nonactive_puts_attr.attr,
&zcache_failed_pers_puts_attr.attr,
&zcache_policy_percent_exceeded_attr.attr,
&zcache_compress_poor_attr.attr,
&zcache_mean_compress_poor_attr.attr,
&zcache_zbud_curr_raw_pages_attr.attr,
&zcache_zbud_curr_zpages_attr.attr,
&zcache_zbud_curr_zbytes_attr.attr,
&zcache_zbud_cumul_zpages_attr.attr,
&zcache_zbud_cumul_zbytes_attr.attr,
&zcache_zbud_buddied_count_attr.attr,
&zcache_evicted_raw_pages_attr.attr,
&zcache_evicted_unbuddied_pages_attr.attr,
&zcache_evicted_buddied_pages_attr.attr,
&zcache_failed_get_free_pages_attr.attr,
&zcache_failed_alloc_attr.attr,
&zcache_put_to_flush_attr.attr,
&zcache_zbud_unbuddied_list_counts_attr.attr,
&zcache_zbud_cumul_chunk_counts_attr.attr,
&zcache_zv_curr_dist_counts_attr.attr,
&zcache_zv_cumul_dist_counts_attr.attr,
&zcache_zv_max_zsize_attr.attr,
&zcache_zv_max_mean_zsize_attr.attr,
&zcache_zv_page_count_policy_percent_attr.attr,
NULL,
};
static struct attribute_group zcache_attr_group = {
.attrs = zcache_attrs,
.name = "zcache",
};
#define RAMSTER_SYSFS_RO(_name) \
static ssize_t ramster_##_name##_show(struct kobject *kobj, \
struct kobj_attribute *attr, char *buf) \
{ \
return sprintf(buf, "%lu\n", ramster_##_name); \
} \
static struct kobj_attribute ramster_##_name##_attr = { \
.attr = { .name = __stringify(_name), .mode = 0444 }, \
.show = ramster_##_name##_show, \
}
#define RAMSTER_SYSFS_RW(_name) \
static ssize_t ramster_##_name##_show(struct kobject *kobj, \
struct kobj_attribute *attr, char *buf) \
{ \
return sprintf(buf, "%lu\n", ramster_##_name); \
} \
static ssize_t ramster_##_name##_store(struct kobject *kobj, \
struct kobj_attribute *attr, const char *buf, size_t count) \
{ \
int err; \
unsigned long enable; \
err = kstrtoul(buf, 10, &enable); \
if (err) \
return -EINVAL; \
ramster_##_name = enable; \
return count; \
} \
static struct kobj_attribute ramster_##_name##_attr = { \
.attr = { .name = __stringify(_name), .mode = 0644 }, \
.show = ramster_##_name##_show, \
.store = ramster_##_name##_store, \
}
#define RAMSTER_SYSFS_RO_ATOMIC(_name) \
static ssize_t ramster_##_name##_show(struct kobject *kobj, \
struct kobj_attribute *attr, char *buf) \
{ \
return sprintf(buf, "%d\n", atomic_read(&ramster_##_name)); \
} \
static struct kobj_attribute ramster_##_name##_attr = { \
.attr = { .name = __stringify(_name), .mode = 0444 }, \
.show = ramster_##_name##_show, \
}
RAMSTER_SYSFS_RO(interface_revision);
RAMSTER_SYSFS_RO_ATOMIC(remote_pers_pages);
RAMSTER_SYSFS_RW(pers_remotify_enable);
RAMSTER_SYSFS_RW(eph_remotify_enable);
RAMSTER_SYSFS_RO(eph_pages_remoted);
RAMSTER_SYSFS_RO(eph_pages_remote_failed);
RAMSTER_SYSFS_RO(pers_pages_remoted);
RAMSTER_SYSFS_RO(pers_pages_remote_failed);
RAMSTER_SYSFS_RO(pers_pages_remote_nomem);
RAMSTER_SYSFS_RO(remote_pages_flushed);
RAMSTER_SYSFS_RO(remote_page_flushes_failed);
RAMSTER_SYSFS_RO(remote_objects_flushed);
RAMSTER_SYSFS_RO(remote_object_flushes_failed);
RAMSTER_SYSFS_RO(remote_eph_pages_succ_get);
RAMSTER_SYSFS_RO(remote_eph_pages_unsucc_get);
RAMSTER_SYSFS_RO(remote_pers_pages_succ_get);
RAMSTER_SYSFS_RO(remote_pers_pages_unsucc_get);
RAMSTER_SYSFS_RO_ATOMIC(foreign_eph_pampd_count);
RAMSTER_SYSFS_RO(foreign_eph_pampd_count_max);
RAMSTER_SYSFS_RO_ATOMIC(foreign_pers_pampd_count);
RAMSTER_SYSFS_RO(foreign_pers_pampd_count_max);
RAMSTER_SYSFS_RO_ATOMIC(curr_flnode_count);
RAMSTER_SYSFS_RO(curr_flnode_count_max);
#define MANUAL_NODES 8
static bool ramster_nodes_manual_up[MANUAL_NODES];
static ssize_t ramster_manual_node_up_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
int i;
char *p = buf;
for (i = 0; i < MANUAL_NODES; i++)
if (ramster_nodes_manual_up[i])
p += sprintf(p, "%d ", i);
p += sprintf(p, "\n");
return p - buf;
}
static ssize_t ramster_manual_node_up_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
int err;
unsigned long node_num;
err = kstrtoul(buf, 10, &node_num);
if (err) {
pr_err("ramster: bad strtoul?\n");
return -EINVAL;
}
if (node_num >= MANUAL_NODES) {
pr_err("ramster: bad node_num=%lu?\n", node_num);
return -EINVAL;
}
if (ramster_nodes_manual_up[node_num]) {
pr_err("ramster: node %d already up, ignoring\n",
(int)node_num);
} else {
ramster_nodes_manual_up[node_num] = true;
r2net_hb_node_up_manual((int)node_num);
}
return count;
}
static struct kobj_attribute ramster_manual_node_up_attr = {
.attr = { .name = "manual_node_up", .mode = 0644 },
.show = ramster_manual_node_up_show,
.store = ramster_manual_node_up_store,
};
static ssize_t ramster_remote_target_nodenum_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
if (ramster_remote_target_nodenum == -1UL)
return sprintf(buf, "unset\n");
else
return sprintf(buf, "%d\n", ramster_remote_target_nodenum);
}
static ssize_t ramster_remote_target_nodenum_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
int err;
unsigned long node_num;
err = kstrtoul(buf, 10, &node_num);
if (err) {
pr_err("ramster: bad strtoul?\n");
return -EINVAL;
} else if (node_num == -1UL) {
pr_err("ramster: disabling all remotification, "
"data may still reside on remote nodes however\n");
return -EINVAL;
} else if (node_num >= MANUAL_NODES) {
pr_err("ramster: bad node_num=%lu?\n", node_num);
return -EINVAL;
} else if (!ramster_nodes_manual_up[node_num]) {
pr_err("ramster: node %d not up, ignoring setting "
"of remotification target\n", (int)node_num);
} else if (r2net_remote_target_node_set((int)node_num) >= 0) {
pr_info("ramster: node %d set as remotification target\n",
(int)node_num);
ramster_remote_target_nodenum = (int)node_num;
} else {
pr_err("ramster: bad num to node node_num=%d?\n",
(int)node_num);
return -EINVAL;
}
return count;
}
static struct kobj_attribute ramster_remote_target_nodenum_attr = {
.attr = { .name = "remote_target_nodenum", .mode = 0644 },
.show = ramster_remote_target_nodenum_show,
.store = ramster_remote_target_nodenum_store,
};
static struct attribute *ramster_attrs[] = {
&ramster_interface_revision_attr.attr,
&ramster_pers_remotify_enable_attr.attr,
&ramster_eph_remotify_enable_attr.attr,
&ramster_remote_pers_pages_attr.attr,
&ramster_eph_pages_remoted_attr.attr,
&ramster_eph_pages_remote_failed_attr.attr,
&ramster_pers_pages_remoted_attr.attr,
&ramster_pers_pages_remote_failed_attr.attr,
&ramster_pers_pages_remote_nomem_attr.attr,
&ramster_remote_pages_flushed_attr.attr,
&ramster_remote_page_flushes_failed_attr.attr,
&ramster_remote_objects_flushed_attr.attr,
&ramster_remote_object_flushes_failed_attr.attr,
&ramster_remote_eph_pages_succ_get_attr.attr,
&ramster_remote_eph_pages_unsucc_get_attr.attr,
&ramster_remote_pers_pages_succ_get_attr.attr,
&ramster_remote_pers_pages_unsucc_get_attr.attr,
&ramster_foreign_eph_pampd_count_attr.attr,
&ramster_foreign_eph_pampd_count_max_attr.attr,
&ramster_foreign_pers_pampd_count_attr.attr,
&ramster_foreign_pers_pampd_count_max_attr.attr,
&ramster_curr_flnode_count_attr.attr,
&ramster_curr_flnode_count_max_attr.attr,
&ramster_manual_node_up_attr.attr,
&ramster_remote_target_nodenum_attr.attr,
NULL,
};
static struct attribute_group ramster_attr_group = {
.attrs = ramster_attrs,
.name = "ramster",
};
#endif /* CONFIG_SYSFS */
/*
* When zcache is disabled ("frozen"), pools can be created and destroyed,
* but all puts (and thus all other operations that require memory allocation)
* must fail. If zcache is unfrozen, accepts puts, then frozen again,
* data consistency requires all puts while frozen to be converted into
* flushes.
*/
static bool zcache_freeze;
/*
* zcache shrinker interface (only useful for ephemeral pages, so zbud only)
*/
static int shrink_zcache_memory(struct shrinker *shrink,
struct shrink_control *sc)
{
int ret = -1;
int nr = sc->nr_to_scan;
gfp_t gfp_mask = sc->gfp_mask;
if (nr >= 0) {
if (!(gfp_mask & __GFP_FS))
/* does this case really need to be skipped? */
goto out;
zbud_evict_pages(nr);
}
ret = (int)atomic_read(&zcache_zbud_curr_raw_pages);
out:
return ret;
}
static struct shrinker zcache_shrinker = {
.shrink = shrink_zcache_memory,
.seeks = DEFAULT_SEEKS,
};
/*
* zcache shims between cleancache/frontswap ops and tmem
*/
int zcache_put(int cli_id, int pool_id, struct tmem_oid *oidp,
uint32_t index, char *data, size_t size,
bool raw, int ephemeral)
{
struct tmem_pool *pool;
int ret = -1;
BUG_ON(!irqs_disabled());
pool = zcache_get_pool_by_id(cli_id, pool_id);
if (unlikely(pool == NULL))
goto out;
if (!zcache_freeze && zcache_do_preload(pool) == 0) {
/* preload does preempt_disable on success */
ret = tmem_put(pool, oidp, index, data, size, raw, ephemeral);
if (ret < 0) {
if (is_ephemeral(pool))
zcache_failed_eph_puts++;
else
zcache_failed_pers_puts++;
}
zcache_put_pool(pool);
preempt_enable_no_resched();
} else {
zcache_put_to_flush++;
if (atomic_read(&pool->obj_count) > 0)
/* the put fails whether the flush succeeds or not */
(void)tmem_flush_page(pool, oidp, index);
zcache_put_pool(pool);
}
out:
return ret;
}
int zcache_get(int cli_id, int pool_id, struct tmem_oid *oidp,
uint32_t index, char *data, size_t *sizep,
bool raw, int get_and_free)
{
struct tmem_pool *pool;
int ret = -1;
bool eph;
if (!raw) {
BUG_ON(irqs_disabled());
BUG_ON(in_softirq());
}
pool = zcache_get_pool_by_id(cli_id, pool_id);
eph = is_ephemeral(pool);
if (likely(pool != NULL)) {
if (atomic_read(&pool->obj_count) > 0)
ret = tmem_get(pool, oidp, index, data, sizep,
raw, get_and_free);
zcache_put_pool(pool);
}
WARN_ONCE((!eph && (ret != 0)), "zcache_get fails on persistent pool, "
"bad things are very likely to happen soon\n");
#ifdef RAMSTER_TESTING
if (ret != 0 && ret != -1 && !(ret == -EINVAL && is_ephemeral(pool)))
pr_err("TESTING zcache_get tmem_get returns ret=%d\n", ret);
#endif
if (ret == -EAGAIN)
BUG(); /* FIXME... don't need this anymore??? let's ensure */
return ret;
}
int zcache_flush(int cli_id, int pool_id,
struct tmem_oid *oidp, uint32_t index)
{
struct tmem_pool *pool;
int ret = -1;
unsigned long flags;
local_irq_save(flags);
zcache_flush_total++;
pool = zcache_get_pool_by_id(cli_id, pool_id);
ramster_do_preload_flnode_only(pool);
if (likely(pool != NULL)) {
if (atomic_read(&pool->obj_count) > 0)
ret = tmem_flush_page(pool, oidp, index);
zcache_put_pool(pool);
}
if (ret >= 0)
zcache_flush_found++;
local_irq_restore(flags);
return ret;
}
int zcache_flush_object(int cli_id, int pool_id, struct tmem_oid *oidp)
{
struct tmem_pool *pool;
int ret = -1;
unsigned long flags;
local_irq_save(flags);
zcache_flobj_total++;
pool = zcache_get_pool_by_id(cli_id, pool_id);
ramster_do_preload_flnode_only(pool);
if (likely(pool != NULL)) {
if (atomic_read(&pool->obj_count) > 0)
ret = tmem_flush_object(pool, oidp);
zcache_put_pool(pool);
}
if (ret >= 0)
zcache_flobj_found++;
local_irq_restore(flags);
return ret;
}
int zcache_client_destroy_pool(int cli_id, int pool_id)
{
struct tmem_pool *pool = NULL;
struct zcache_client *cli = NULL;
int ret = -1;
if (pool_id < 0)
goto out;
if (cli_id == LOCAL_CLIENT)
cli = &zcache_host;
else if ((unsigned int)cli_id < MAX_CLIENTS)
cli = &zcache_clients[cli_id];
if (cli == NULL)
goto out;
atomic_inc(&cli->refcount);
pool = cli->tmem_pools[pool_id];
if (pool == NULL)
goto out;
cli->tmem_pools[pool_id] = NULL;
/* wait for pool activity on other cpus to quiesce */
while (atomic_read(&pool->refcount) != 0)
;
atomic_dec(&cli->refcount);
local_bh_disable();
ret = tmem_destroy_pool(pool);
local_bh_enable();
kfree(pool);
pr_info("ramster: destroyed pool id=%d cli_id=%d\n", pool_id, cli_id);
out:
return ret;
}
static int zcache_destroy_pool(int pool_id)
{
return zcache_client_destroy_pool(LOCAL_CLIENT, pool_id);
}
int zcache_new_pool(uint16_t cli_id, uint32_t flags)
{
int poolid = -1;
struct tmem_pool *pool;
struct zcache_client *cli = NULL;
if (cli_id == LOCAL_CLIENT)
cli = &zcache_host;
else if ((unsigned int)cli_id < MAX_CLIENTS)
cli = &zcache_clients[cli_id];
if (cli == NULL)
goto out;
atomic_inc(&cli->refcount);
pool = kmalloc(sizeof(struct tmem_pool), GFP_ATOMIC);
if (pool == NULL) {
pr_info("ramster: pool creation failed: out of memory\n");
goto out;
}
for (poolid = 0; poolid < MAX_POOLS_PER_CLIENT; poolid++)
if (cli->tmem_pools[poolid] == NULL)
break;
if (poolid >= MAX_POOLS_PER_CLIENT) {
pr_info("ramster: pool creation failed: max exceeded\n");
kfree(pool);
poolid = -1;
goto out;
}
atomic_set(&pool->refcount, 0);
pool->client = cli;
pool->pool_id = poolid;
tmem_new_pool(pool, flags);
cli->tmem_pools[poolid] = pool;
if (cli_id == LOCAL_CLIENT)
pr_info("ramster: created %s tmem pool, id=%d, local client\n",
flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral",
poolid);
else
pr_info("ramster: created %s tmem pool, id=%d, client=%d\n",
flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral",
poolid, cli_id);
out:
if (cli != NULL)
atomic_dec(&cli->refcount);
return poolid;
}
static int zcache_local_new_pool(uint32_t flags)
{
return zcache_new_pool(LOCAL_CLIENT, flags);
}
int zcache_autocreate_pool(int cli_id, int pool_id, bool ephemeral)
{
struct tmem_pool *pool;
struct zcache_client *cli = NULL;
uint32_t flags = ephemeral ? 0 : TMEM_POOL_PERSIST;
int ret = -1;
if (cli_id == LOCAL_CLIENT)
goto out;
if (pool_id >= MAX_POOLS_PER_CLIENT)
goto out;
else if ((unsigned int)cli_id < MAX_CLIENTS)
cli = &zcache_clients[cli_id];
if ((ephemeral && !use_cleancache) || (!ephemeral && !use_frontswap))
BUG(); /* FIXME, handle more gracefully later */
if (!cli->allocated) {
if (zcache_new_client(cli_id))
BUG(); /* FIXME, handle more gracefully later */
cli = &zcache_clients[cli_id];
}
atomic_inc(&cli->refcount);
pool = cli->tmem_pools[pool_id];
if (pool != NULL) {
if (pool->persistent && ephemeral) {
pr_err("zcache_autocreate_pool: type mismatch\n");
goto out;
}
ret = 0;
goto out;
}
pool = kmalloc(sizeof(struct tmem_pool), GFP_KERNEL);
if (pool == NULL) {
pr_info("ramster: pool creation failed: out of memory\n");
goto out;
}
atomic_set(&pool->refcount, 0);
pool->client = cli;
pool->pool_id = pool_id;
tmem_new_pool(pool, flags);
cli->tmem_pools[pool_id] = pool;
pr_info("ramster: AUTOcreated %s tmem poolid=%d, for remote client=%d\n",
flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral",
pool_id, cli_id);
ret = 0;
out:
if (cli == NULL)
BUG(); /* FIXME, handle more gracefully later */
/* pr_err("zcache_autocreate_pool: failed\n"); */
if (cli != NULL)
atomic_dec(&cli->refcount);
return ret;
}
/**********
* Two kernel functionalities currently can be layered on top of tmem.
* These are "cleancache" which is used as a second-chance cache for clean
* page cache pages; and "frontswap" which is used for swap pages
* to avoid writes to disk. A generic "shim" is provided here for each
* to translate in-kernel semantics to zcache semantics.
*/
#ifdef CONFIG_CLEANCACHE
static void zcache_cleancache_put_page(int pool_id,
struct cleancache_filekey key,
pgoff_t index, struct page *page)
{
u32 ind = (u32) index;
struct tmem_oid oid = *(struct tmem_oid *)&key;
#ifdef __PG_WAS_ACTIVE
if (!PageWasActive(page)) {
zcache_nonactive_puts++;
return;
}
#endif
if (likely(ind == index)) {
char *kva = page_address(page);
(void)zcache_put(LOCAL_CLIENT, pool_id, &oid, index,
kva, PAGE_SIZE, 0, 1);
}
}
static int zcache_cleancache_get_page(int pool_id,
struct cleancache_filekey key,
pgoff_t index, struct page *page)
{
u32 ind = (u32) index;
struct tmem_oid oid = *(struct tmem_oid *)&key;
int ret = -1;
preempt_disable();
if (likely(ind == index)) {
char *kva = page_address(page);
size_t size = PAGE_SIZE;
ret = zcache_get(LOCAL_CLIENT, pool_id, &oid, index,
kva, &size, 0, 0);
#ifdef __PG_WAS_ACTIVE
if (ret == 0)
SetPageWasActive(page);
#endif
}
preempt_enable();
return ret;
}
static void zcache_cleancache_flush_page(int pool_id,
struct cleancache_filekey key,
pgoff_t index)
{
u32 ind = (u32) index;
struct tmem_oid oid = *(struct tmem_oid *)&key;
if (likely(ind == index))
(void)zcache_flush(LOCAL_CLIENT, pool_id, &oid, ind);
}
static void zcache_cleancache_flush_inode(int pool_id,
struct cleancache_filekey key)
{
struct tmem_oid oid = *(struct tmem_oid *)&key;
(void)zcache_flush_object(LOCAL_CLIENT, pool_id, &oid);
}
static void zcache_cleancache_flush_fs(int pool_id)
{
if (pool_id >= 0)
(void)zcache_destroy_pool(pool_id);
}
static int zcache_cleancache_init_fs(size_t pagesize)
{
BUG_ON(sizeof(struct cleancache_filekey) !=
sizeof(struct tmem_oid));
BUG_ON(pagesize != PAGE_SIZE);
return zcache_local_new_pool(0);
}
static int zcache_cleancache_init_shared_fs(char *uuid, size_t pagesize)
{
/* shared pools are unsupported and map to private */
BUG_ON(sizeof(struct cleancache_filekey) !=
sizeof(struct tmem_oid));
BUG_ON(pagesize != PAGE_SIZE);
return zcache_local_new_pool(0);
}
static struct cleancache_ops zcache_cleancache_ops = {
.put_page = zcache_cleancache_put_page,
.get_page = zcache_cleancache_get_page,
.invalidate_page = zcache_cleancache_flush_page,
.invalidate_inode = zcache_cleancache_flush_inode,
.invalidate_fs = zcache_cleancache_flush_fs,
.init_shared_fs = zcache_cleancache_init_shared_fs,
.init_fs = zcache_cleancache_init_fs
};
struct cleancache_ops zcache_cleancache_register_ops(void)
{
struct cleancache_ops old_ops =
cleancache_register_ops(&zcache_cleancache_ops);
return old_ops;
}
#endif
#ifdef CONFIG_FRONTSWAP
/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
static int zcache_frontswap_poolid = -1;
/*
* Swizzling increases objects per swaptype, increasing tmem concurrency
* for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS
*/
#define SWIZ_BITS 8
#define SWIZ_MASK ((1 << SWIZ_BITS) - 1)
#define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK))
#define iswiz(_ind) (_ind >> SWIZ_BITS)
static inline struct tmem_oid oswiz(unsigned type, u32 ind)
{
struct tmem_oid oid = { .oid = { 0 } };
oid.oid[0] = _oswiz(type, ind);
return oid;
}
static int zcache_frontswap_store(unsigned type, pgoff_t offset,
struct page *page)
{
u64 ind64 = (u64)offset;
u32 ind = (u32)offset;
struct tmem_oid oid = oswiz(type, ind);
int ret = -1;
unsigned long flags;
char *kva;
BUG_ON(!PageLocked(page));
if (likely(ind64 == ind)) {
local_irq_save(flags);
kva = page_address(page);
ret = zcache_put(LOCAL_CLIENT, zcache_frontswap_poolid,
&oid, iswiz(ind), kva, PAGE_SIZE, 0, 0);
local_irq_restore(flags);
}
return ret;
}
/* returns 0 if the page was successfully gotten from frontswap, -1 if
* was not present (should never happen!) */
static int zcache_frontswap_load(unsigned type, pgoff_t offset,
struct page *page)
{
u64 ind64 = (u64)offset;
u32 ind = (u32)offset;
struct tmem_oid oid = oswiz(type, ind);
int ret = -1;
preempt_disable(); /* FIXME, remove this? */
BUG_ON(!PageLocked(page));
if (likely(ind64 == ind)) {
char *kva = page_address(page);
size_t size = PAGE_SIZE;
ret = zcache_get(LOCAL_CLIENT, zcache_frontswap_poolid,
&oid, iswiz(ind), kva, &size, 0, -1);
}
preempt_enable(); /* FIXME, remove this? */
return ret;
}
/* flush a single page from frontswap */
static void zcache_frontswap_flush_page(unsigned type, pgoff_t offset)
{
u64 ind64 = (u64)offset;
u32 ind = (u32)offset;
struct tmem_oid oid = oswiz(type, ind);
if (likely(ind64 == ind))
(void)zcache_flush(LOCAL_CLIENT, zcache_frontswap_poolid,
&oid, iswiz(ind));
}
/* flush all pages from the passed swaptype */
static void zcache_frontswap_flush_area(unsigned type)
{
struct tmem_oid oid;
int ind;
for (ind = SWIZ_MASK; ind >= 0; ind--) {
oid = oswiz(type, ind);
(void)zcache_flush_object(LOCAL_CLIENT,
zcache_frontswap_poolid, &oid);
}
}
static void zcache_frontswap_init(unsigned ignored)
{
/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
if (zcache_frontswap_poolid < 0)
zcache_frontswap_poolid =
zcache_local_new_pool(TMEM_POOL_PERSIST);
}
static struct frontswap_ops zcache_frontswap_ops = {
.store = zcache_frontswap_store,
.load = zcache_frontswap_load,
.invalidate_page = zcache_frontswap_flush_page,
.invalidate_area = zcache_frontswap_flush_area,
.init = zcache_frontswap_init
};
struct frontswap_ops zcache_frontswap_register_ops(void)
{
struct frontswap_ops old_ops =
frontswap_register_ops(&zcache_frontswap_ops);
return old_ops;
}
#endif
/*
* frontswap selfshrinking
*/
#ifdef CONFIG_FRONTSWAP
/* In HZ, controls frequency of worker invocation. */
static unsigned int selfshrink_interval __read_mostly = 5;
static void selfshrink_process(struct work_struct *work);
static DECLARE_DELAYED_WORK(selfshrink_worker, selfshrink_process);
/* Enable/disable with sysfs. */
static bool frontswap_selfshrinking __read_mostly;
/* Enable/disable with kernel boot option. */
static bool use_frontswap_selfshrink __initdata = true;
/*
* The default values for the following parameters were deemed reasonable
* by experimentation, may be workload-dependent, and can all be
* adjusted via sysfs.
*/
/* Control rate for frontswap shrinking. Higher hysteresis is slower. */
static unsigned int frontswap_hysteresis __read_mostly = 20;
/*
* Number of selfshrink worker invocations to wait before observing that
* frontswap selfshrinking should commence. Note that selfshrinking does
* not use a separate worker thread.
*/
static unsigned int frontswap_inertia __read_mostly = 3;
/* Countdown to next invocation of frontswap_shrink() */
static unsigned long frontswap_inertia_counter;
/*
* Invoked by the selfshrink worker thread, uses current number of pages
* in frontswap (frontswap_curr_pages()), previous status, and control
* values (hysteresis and inertia) to determine if frontswap should be
* shrunk and what the new frontswap size should be. Note that
* frontswap_shrink is essentially a partial swapoff that immediately
* transfers pages from the "swap device" (frontswap) back into kernel
* RAM; despite the name, frontswap "shrinking" is very different from
* the "shrinker" interface used by the kernel MM subsystem to reclaim
* memory.
*/
static void frontswap_selfshrink(void)
{
static unsigned long cur_frontswap_pages;
static unsigned long last_frontswap_pages;
static unsigned long tgt_frontswap_pages;
last_frontswap_pages = cur_frontswap_pages;
cur_frontswap_pages = frontswap_curr_pages();
if (!cur_frontswap_pages ||
(cur_frontswap_pages > last_frontswap_pages)) {
frontswap_inertia_counter = frontswap_inertia;
return;
}
if (frontswap_inertia_counter && --frontswap_inertia_counter)
return;
if (cur_frontswap_pages <= frontswap_hysteresis)
tgt_frontswap_pages = 0;
else
tgt_frontswap_pages = cur_frontswap_pages -
(cur_frontswap_pages / frontswap_hysteresis);
frontswap_shrink(tgt_frontswap_pages);
}
static int __init ramster_nofrontswap_selfshrink_setup(char *s)
{
use_frontswap_selfshrink = false;
return 1;
}
__setup("noselfshrink", ramster_nofrontswap_selfshrink_setup);
static void selfshrink_process(struct work_struct *work)
{
if (frontswap_selfshrinking && frontswap_enabled) {
frontswap_selfshrink();
schedule_delayed_work(&selfshrink_worker,
selfshrink_interval * HZ);
}
}
static int ramster_enabled;
static int __init ramster_selfshrink_init(void)
{
frontswap_selfshrinking = ramster_enabled && use_frontswap_selfshrink;
if (frontswap_selfshrinking)
pr_info("ramster: Initializing frontswap "
"selfshrinking driver.\n");
else
return -ENODEV;
schedule_delayed_work(&selfshrink_worker, selfshrink_interval * HZ);
return 0;
}
subsys_initcall(ramster_selfshrink_init);
#endif
/*
* zcache initialization
* NOTE FOR NOW ramster MUST BE PROVIDED AS A KERNEL BOOT PARAMETER OR
* NOTHING HAPPENS!
*/
static int ramster_enabled;
static int __init enable_ramster(char *s)
{
ramster_enabled = 1;
return 1;
}
__setup("ramster", enable_ramster);
/* allow independent dynamic disabling of cleancache and frontswap */
static int use_cleancache = 1;
static int __init no_cleancache(char *s)
{
pr_info("INIT no_cleancache called\n");
use_cleancache = 0;
return 1;
}
/*
* FIXME: need to guarantee this gets checked before zcache_init is called
* What is the correct way to achieve this?
*/
early_param("nocleancache", no_cleancache);
static int use_frontswap = 1;
static int __init no_frontswap(char *s)
{
pr_info("INIT no_frontswap called\n");
use_frontswap = 0;
return 1;
}
__setup("nofrontswap", no_frontswap);
static int __init zcache_init(void)
{
int ret = 0;
#ifdef CONFIG_SYSFS
ret = sysfs_create_group(mm_kobj, &zcache_attr_group);
ret = sysfs_create_group(mm_kobj, &ramster_attr_group);
if (ret) {
pr_err("ramster: can't create sysfs\n");
goto out;
}
#endif /* CONFIG_SYSFS */
#if defined(CONFIG_CLEANCACHE) || defined(CONFIG_FRONTSWAP)
if (ramster_enabled) {
unsigned int cpu;
(void)r2net_register_handlers();
tmem_register_hostops(&zcache_hostops);
tmem_register_pamops(&zcache_pamops);
ret = register_cpu_notifier(&zcache_cpu_notifier_block);
if (ret) {
pr_err("ramster: can't register cpu notifier\n");
goto out;
}
for_each_online_cpu(cpu) {
void *pcpu = (void *)(long)cpu;
zcache_cpu_notifier(&zcache_cpu_notifier_block,
CPU_UP_PREPARE, pcpu);
}
}
zcache_objnode_cache = kmem_cache_create("zcache_objnode",
sizeof(struct tmem_objnode), 0, 0, NULL);
zcache_obj_cache = kmem_cache_create("zcache_obj",
sizeof(struct tmem_obj), 0, 0, NULL);
ramster_flnode_cache = kmem_cache_create("ramster_flnode",
sizeof(struct flushlist_node), 0, 0, NULL);
#endif
#ifdef CONFIG_CLEANCACHE
pr_info("INIT ramster_enabled=%d use_cleancache=%d\n",
ramster_enabled, use_cleancache);
if (ramster_enabled && use_cleancache) {
struct cleancache_ops old_ops;
zbud_init();
register_shrinker(&zcache_shrinker);
old_ops = zcache_cleancache_register_ops();
pr_info("ramster: cleancache enabled using kernel "
"transcendent memory and compression buddies\n");
if (old_ops.init_fs != NULL)
pr_warning("ramster: cleancache_ops overridden");
}
#endif
#ifdef CONFIG_FRONTSWAP
pr_info("INIT ramster_enabled=%d use_frontswap=%d\n",
ramster_enabled, use_frontswap);
if (ramster_enabled && use_frontswap) {
struct frontswap_ops old_ops;
zcache_new_client(LOCAL_CLIENT);
old_ops = zcache_frontswap_register_ops();
pr_info("ramster: frontswap enabled using kernel "
"transcendent memory and xvmalloc\n");
if (old_ops.init != NULL)
pr_warning("ramster: frontswap_ops overridden");
}
if (ramster_enabled && (use_frontswap || use_cleancache))
ramster_remotify_init();
#endif
out:
return ret;
}
module_init(zcache_init)
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