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zcache-main.c
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zcache-main.c
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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);
}
}