| /* |
| * zcache.c |
| * |
| * Copyright (c) 2010,2011, 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 the crypto compression |
| * API: |
| * 1) "compression buddies" ("zbud") is used for ephemeral pages |
| * 2) zsmalloc 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 |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/cpu.h> |
| #include <linux/highmem.h> |
| #include <linux/list.h> |
| #include <linux/slab.h> |
| #include <linux/spinlock.h> |
| #include <linux/types.h> |
| #include <linux/atomic.h> |
| #include <linux/math64.h> |
| #include <linux/crypto.h> |
| #include <linux/string.h> |
| #include <linux/idr.h> |
| #include "tmem.h" |
| |
| #include "../zsmalloc/zsmalloc.h" |
| |
| #ifdef CONFIG_CLEANCACHE |
| #include <linux/cleancache.h> |
| #endif |
| #ifdef CONFIG_FRONTSWAP |
| #include <linux/frontswap.h> |
| #endif |
| |
| #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_CLIENTS 16 |
| #define LOCAL_CLIENT ((uint16_t)-1) |
| |
| MODULE_LICENSE("GPL"); |
| |
| struct zcache_client { |
| struct idr tmem_pools; |
| struct zs_pool *zspool; |
| 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 struct zcache_client *get_zcache_client(uint16_t cli_id) |
| { |
| if (cli_id == LOCAL_CLIENT) |
| return &zcache_host; |
| |
| if ((unsigned int)cli_id < MAX_CLIENTS) |
| return &zcache_clients[cli_id]; |
| |
| return NULL; |
| } |
| |
| static inline bool is_local_client(struct zcache_client *cli) |
| { |
| return cli == &zcache_host; |
| } |
| |
| /* crypto API for zcache */ |
| #define ZCACHE_COMP_NAME_SZ CRYPTO_MAX_ALG_NAME |
| static char zcache_comp_name[ZCACHE_COMP_NAME_SZ]; |
| static struct crypto_comp * __percpu *zcache_comp_pcpu_tfms; |
| |
| enum comp_op { |
| ZCACHE_COMPOP_COMPRESS, |
| ZCACHE_COMPOP_DECOMPRESS |
| }; |
| |
| static inline int zcache_comp_op(enum comp_op op, |
| const u8 *src, unsigned int slen, |
| u8 *dst, unsigned int *dlen) |
| { |
| struct crypto_comp *tfm; |
| int ret; |
| |
| BUG_ON(!zcache_comp_pcpu_tfms); |
| tfm = *per_cpu_ptr(zcache_comp_pcpu_tfms, get_cpu()); |
| BUG_ON(!tfm); |
| switch (op) { |
| case ZCACHE_COMPOP_COMPRESS: |
| ret = crypto_comp_compress(tfm, src, slen, dst, dlen); |
| break; |
| case ZCACHE_COMPOP_DECOMPRESS: |
| ret = crypto_comp_decompress(tfm, src, slen, dst, dlen); |
| break; |
| default: |
| ret = -EINVAL; |
| } |
| put_cpu(); |
| return ret; |
| } |
| |
| /********** |
| * 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. |
| */ |
| |
| #define ZBH_SENTINEL 0x43214321 |
| #define ZBPG_SENTINEL 0xdeadbeef |
| |
| #define ZBUD_MAX_BUDS 2 |
| |
| struct zbud_hdr { |
| 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 |
| }; |
| |
| 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 LIST_HEAD(zbpg_unused_list); |
| static unsigned long zcache_zbpg_unused_list_count; |
| |
| /* protects the unused page list */ |
| static DEFINE_SPINLOCK(zbpg_unused_list_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_mean_compress_poor; |
| |
| /* 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; |
| } |
| |
| /* |
| * zbud raw page management |
| */ |
| |
| static struct zbud_page *zbud_alloc_raw_page(void) |
| { |
| struct zbud_page *zbpg = NULL; |
| struct zbud_hdr *zh0, *zh1; |
| bool recycled = 0; |
| |
| /* if any pages on the zbpg list, use one */ |
| spin_lock(&zbpg_unused_list_spinlock); |
| if (!list_empty(&zbpg_unused_list)) { |
| zbpg = list_first_entry(&zbpg_unused_list, |
| struct zbud_page, bud_list); |
| list_del_init(&zbpg->bud_list); |
| zcache_zbpg_unused_list_count--; |
| recycled = 1; |
| } |
| spin_unlock(&zbpg_unused_list_spinlock); |
| if (zbpg == NULL) |
| /* none on zbpg list, try to get a kernel page */ |
| 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); |
| if (recycled) { |
| ASSERT_INVERTED_SENTINEL(zbpg, ZBPG); |
| SET_SENTINEL(zbpg, ZBPG); |
| BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid)); |
| BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid)); |
| } else { |
| 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); |
| spin_lock(&zbpg_unused_list_spinlock); |
| list_add(&zbpg->bud_list, &zbpg_unused_list); |
| zcache_zbpg_unused_list_count++; |
| spin_unlock(&zbpg_unused_list_spinlock); |
| } |
| |
| /* |
| * 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]); |
| |
| spin_lock(&zbud_budlists_spinlock); |
| spin_lock(&zbpg->lock); |
| if (list_empty(&zbpg->bud_list)) { |
| /* ignore zombie page... see zbud_evict_pages() */ |
| spin_unlock(&zbpg->lock); |
| spin_unlock(&zbud_budlists_spinlock); |
| 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) ; |
| 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) ; |
| 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); |
| unsigned int 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 = zcache_comp_op(ZCACHE_COMPOP_DECOMPRESS, from_va, size, |
| to_va, &out_len); |
| BUG_ON(ret); |
| 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; |
| |
| ASSERT_SPINLOCK(&zbpg->lock); |
| BUG_ON(!list_empty(&zbpg->bud_list)); |
| 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++; |
| zbud_free(zh); |
| } |
| } |
| spin_unlock(&zbpg->lock); |
| for (i = 0; i < j; i++) { |
| pool = zcache_get_pool_by_id(client_id[i], pool_id[i]); |
| if (pool != NULL) { |
| tmem_flush_page(pool, &oid[i], index[i]); |
| zcache_put_pool(pool); |
| } |
| } |
| ASSERT_SENTINEL(zbpg, ZBPG); |
| spin_lock(&zbpg->lock); |
| zbud_free_raw_page(zbpg); |
| } |
| |
| /* |
| * 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; |
| |
| /* first try freeing any pages on unused list */ |
| retry_unused_list: |
| spin_lock_bh(&zbpg_unused_list_spinlock); |
| if (!list_empty(&zbpg_unused_list)) { |
| /* can't walk list here, since it may change when unlocked */ |
| zbpg = list_first_entry(&zbpg_unused_list, |
| struct zbud_page, bud_list); |
| list_del_init(&zbpg->bud_list); |
| zcache_zbpg_unused_list_count--; |
| atomic_dec(&zcache_zbud_curr_raw_pages); |
| spin_unlock_bh(&zbpg_unused_list_spinlock); |
| zcache_free_page(zbpg); |
| zcache_evicted_raw_pages++; |
| if (--nr <= 0) |
| goto out; |
| goto retry_unused_list; |
| } |
| spin_unlock_bh(&zbpg_unused_list_spinlock); |
| |
| /* 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; |
| list_del_init(&zbpg->bud_list); |
| zbud_unbuddied[i].count--; |
| spin_unlock(&zbud_budlists_spinlock); |
| zcache_evicted_unbuddied_pages++; |
| /* want budlists unlocked when doing zbpg eviction */ |
| zbud_evict_zbpg(zbpg); |
| local_bh_enable(); |
| if (--nr <= 0) |
| goto out; |
| 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 out; |
| } |
| list_for_each_entry(zbpg, &zbud_buddied_list, bud_list) { |
| if (unlikely(!spin_trylock(&zbpg->lock))) |
| continue; |
| list_del_init(&zbpg->bud_list); |
| zcache_zbud_buddied_count--; |
| spin_unlock(&zbud_budlists_spinlock); |
| zcache_evicted_buddied_pages++; |
| /* want budlists unlocked when doing zbpg eviction */ |
| zbud_evict_zbpg(zbpg); |
| local_bh_enable(); |
| if (--nr <= 0) |
| goto out; |
| goto retry_bud_list; |
| } |
| spin_unlock_bh(&zbud_budlists_spinlock); |
| out: |
| return; |
| } |
| |
| static void __init zbud_init(void) |
| { |
| int i; |
| |
| INIT_LIST_HEAD(&zbud_buddied_list); |
| |
| for (i = 0; i < NCHUNKS; i++) |
| INIT_LIST_HEAD(&zbud_unbuddied[i].list); |
| } |
| |
| #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 slab-based zsmalloc |
| * with the crypto compression API 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. |
| */ |
| |
| #define ZVH_SENTINEL 0x43214321 |
| |
| struct zv_hdr { |
| uint32_t pool_id; |
| struct tmem_oid oid; |
| uint32_t index; |
| size_t size; |
| DECL_SENTINEL |
| }; |
| |
| /* 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 unsigned long zv_create(struct zs_pool *pool, uint32_t pool_id, |
| struct tmem_oid *oid, uint32_t index, |
| void *cdata, unsigned clen) |
| { |
| struct zv_hdr *zv; |
| u32 size = clen + sizeof(struct zv_hdr); |
| int chunks = (size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT; |
| unsigned long handle = 0; |
| |
| BUG_ON(!irqs_disabled()); |
| BUG_ON(chunks >= NCHUNKS); |
| handle = zs_malloc(pool, size); |
| if (!handle) |
| goto out; |
| atomic_inc(&zv_curr_dist_counts[chunks]); |
| atomic_inc(&zv_cumul_dist_counts[chunks]); |
| zv = zs_map_object(pool, handle, ZS_MM_WO); |
| zv->index = index; |
| zv->oid = *oid; |
| zv->pool_id = pool_id; |
| zv->size = clen; |
| SET_SENTINEL(zv, ZVH); |
| memcpy((char *)zv + sizeof(struct zv_hdr), cdata, clen); |
| zs_unmap_object(pool, handle); |
| out: |
| return handle; |
| } |
| |
| static void zv_free(struct zs_pool *pool, unsigned long handle) |
| { |
| unsigned long flags; |
| struct zv_hdr *zv; |
| uint16_t size; |
| int chunks; |
| |
| zv = zs_map_object(pool, handle, ZS_MM_RW); |
| ASSERT_SENTINEL(zv, ZVH); |
| size = zv->size + sizeof(struct zv_hdr); |
| INVERT_SENTINEL(zv, ZVH); |
| zs_unmap_object(pool, handle); |
| |
| chunks = (size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT; |
| BUG_ON(chunks >= NCHUNKS); |
| atomic_dec(&zv_curr_dist_counts[chunks]); |
| |
| local_irq_save(flags); |
| zs_free(pool, handle); |
| local_irq_restore(flags); |
| } |
| |
| static void zv_decompress(struct page *page, unsigned long handle) |
| { |
| unsigned int clen = PAGE_SIZE; |
| char *to_va; |
| int ret; |
| struct zv_hdr *zv; |
| |
| zv = zs_map_object(zcache_host.zspool, handle, ZS_MM_RO); |
| BUG_ON(zv->size == 0); |
| ASSERT_SENTINEL(zv, ZVH); |
| to_va = kmap_atomic(page); |
| ret = zcache_comp_op(ZCACHE_COMPOP_DECOMPRESS, (char *)zv + sizeof(*zv), |
| zv->size, to_va, &clen); |
| kunmap_atomic(to_va); |
| zs_unmap_object(zcache_host.zspool, handle); |
| BUG_ON(ret); |
| BUG_ON(clen != PAGE_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 |
| * arbitary 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_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; |
| |
| cli = get_zcache_client(cli_id); |
| if (!cli) |
| goto out; |
| |
| atomic_inc(&cli->refcount); |
| pool = idr_find(&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; |
| int ret = -1; |
| |
| cli = get_zcache_client(cli_id); |
| |
| if (cli == NULL) |
| goto out; |
| if (cli->allocated) |
| goto out; |
| cli->allocated = 1; |
| #ifdef CONFIG_FRONTSWAP |
| cli->zspool = zs_create_pool("zcache", ZCACHE_GFP_MASK); |
| if (cli->zspool == NULL) |
| goto out; |
| idr_init(&cli->tmem_pools); |
| #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 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]; |
| }; |
| 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; |
| void *page; |
| int ret = -ENOMEM; |
| |
| if (unlikely(zcache_objnode_cache == NULL)) |
| goto out; |
| if (unlikely(zcache_obj_cache == NULL)) |
| goto out; |
| |
| /* IRQ has already been disabled. */ |
| kp = &__get_cpu_var(zcache_preloads); |
| while (kp->nr < ARRAY_SIZE(kp->objnodes)) { |
| objnode = kmem_cache_alloc(zcache_objnode_cache, |
| ZCACHE_GFP_MASK); |
| if (unlikely(objnode == NULL)) { |
| zcache_failed_alloc++; |
| goto out; |
| } |
| |
| kp->objnodes[kp->nr++] = objnode; |
| } |
| |
| if (!kp->obj) { |
| obj = kmem_cache_alloc(zcache_obj_cache, ZCACHE_GFP_MASK); |
| if (unlikely(obj == NULL)) { |
| zcache_failed_alloc++; |
| goto out; |
| } |
| kp->obj = obj; |
| } |
| |
| if (!kp->page) { |
| page = (void *)__get_free_page(ZCACHE_GFP_MASK); |
| if (unlikely(page == NULL)) { |
| zcache_failed_get_free_pages++; |
| goto out; |
| } |
| kp->page = page; |
| } |
| |
| ret = 0; |
| out: |
| 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 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 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, unsigned *out_len); |
| |
| 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, *cdata; |
| unsigned clen; |
| int ret; |
| unsigned long count; |
| struct page *page = (struct page *)(data); |
| struct zcache_client *cli = pool->client; |
| uint16_t client_id = get_client_id_from_client(cli); |
| unsigned long zv_mean_zsize; |
| unsigned long curr_pers_pampd_count; |
| u64 total_zsize; |
| |
| if (eph) { |
| 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) { |
| count = atomic_inc_return(&zcache_curr_eph_pampd_count); |
| if (count > zcache_curr_eph_pampd_count_max) |
| zcache_curr_eph_pampd_count_max = count; |
| } |
| } else { |
| curr_pers_pampd_count = |
| atomic_read(&zcache_curr_pers_pampd_count); |
| if (curr_pers_pampd_count > |
| (zv_page_count_policy_percent * totalram_pages) / 100) |
| goto out; |
| ret = zcache_compress(page, &cdata, &clen); |
| if (ret == 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 = zs_get_total_size_bytes(cli->zspool); |
| 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; |
| } |
| } |
| pampd = (void *)zv_create(cli->zspool, pool->pool_id, |
| oid, index, cdata, clen); |
| if (pampd == NULL) |
| goto out; |
| count = atomic_inc_return(&zcache_curr_pers_pampd_count); |
| if (count > zcache_curr_pers_pampd_count_max) |
| zcache_curr_pers_pampd_count_max = count; |
| } |
| out: |
| 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(is_ephemeral(pool)); |
| zv_decompress((struct page *)(data), (unsigned long)pampd); |
| return ret; |
| } |
| |
| /* |
| * fill the pageframe corresponding to the struct page with the data |
| * from the passed pampd |
| */ |
| 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) |
| { |
| BUG_ON(!is_ephemeral(pool)); |
| if (zbud_decompress((struct page *)(data), pampd) < 0) |
| return -EINVAL; |
| zbud_free_and_delist((struct zbud_hdr *)pampd); |
| atomic_dec(&zcache_curr_eph_pampd_count); |
| return 0; |
| } |
| |
| /* |
| * 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) |
| { |
| struct zcache_client *cli = pool->client; |
| |
| if (is_ephemeral(pool)) { |
| zbud_free_and_delist((struct zbud_hdr *)pampd); |
| atomic_dec(&zcache_curr_eph_pampd_count); |
| BUG_ON(atomic_read(&zcache_curr_eph_pampd_count) < 0); |
| } else { |
| zv_free(cli->zspool, (unsigned long)pampd); |
| atomic_dec(&zcache_curr_pers_pampd_count); |
| BUG_ON(atomic_read(&zcache_curr_pers_pampd_count) < 0); |
| } |
| } |
| |
| static void zcache_pampd_free_obj(struct tmem_pool *pool, struct tmem_obj *obj) |
| { |
| } |
| |
| static void zcache_pampd_new_obj(struct tmem_obj *obj) |
| { |
| } |
| |
| static int zcache_pampd_replace_in_obj(void *pampd, struct tmem_obj *obj) |
| { |
| return -1; |
| } |
| |
| static bool zcache_pampd_is_remote(void *pampd) |
| { |
| return 0; |
| } |
| |
| static struct tmem_pamops zcache_pamops = { |
| .create = zcache_pampd_create, |
| .get_data = zcache_pampd_get_data, |
| .get_data_and_free = zcache_pampd_get_data_and_free, |
| .free = zcache_pampd_free, |
| .free_obj = zcache_pampd_free_obj, |
| .new_obj = zcache_pampd_new_obj, |
| .replace_in_obj = zcache_pampd_replace_in_obj, |
| .is_remote = zcache_pampd_is_remote, |
| }; |
| |
| /* |
| * zcache compression/decompression and related per-cpu stuff |
| */ |
| |
| static DEFINE_PER_CPU(unsigned char *, zcache_dstmem); |
| #define ZCACHE_DSTMEM_ORDER 1 |
| |
| static int zcache_compress(struct page *from, void **out_va, unsigned *out_len) |
| { |
| int ret = 0; |
| unsigned char *dmem = __get_cpu_var(zcache_dstmem); |
| char *from_va; |
| |
| BUG_ON(!irqs_disabled()); |
| if (unlikely(dmem == NULL)) |
| goto out; /* no buffer or no compressor so can't compress */ |
| *out_len = PAGE_SIZE << ZCACHE_DSTMEM_ORDER; |
| from_va = kmap_atomic(from); |
| mb(); |
| ret = zcache_comp_op(ZCACHE_COMPOP_COMPRESS, from_va, PAGE_SIZE, dmem, |
| out_len); |
| BUG_ON(ret); |
| *out_va = dmem; |
| kunmap_atomic(from_va); |
| ret = 1; |
| out: |
| return ret; |
| } |
| |
| static int zcache_comp_cpu_up(int cpu) |
| { |
| struct crypto_comp *tfm; |
| |
| tfm = crypto_alloc_comp(zcache_comp_name, 0, 0); |
| if (IS_ERR(tfm)) |
| return NOTIFY_BAD; |
| *per_cpu_ptr(zcache_comp_pcpu_tfms, cpu) = tfm; |
| return NOTIFY_OK; |
| } |
| |
| static void zcache_comp_cpu_down(int cpu) |
| { |
| struct crypto_comp *tfm; |
| |
| tfm = *per_cpu_ptr(zcache_comp_pcpu_tfms, cpu); |
| crypto_free_comp(tfm); |
| *per_cpu_ptr(zcache_comp_pcpu_tfms, cpu) = NULL; |
| } |
| |
| static int zcache_cpu_notifier(struct notifier_block *nb, |
| unsigned long action, void *pcpu) |
| { |
| int ret, cpu = (long)pcpu; |
| struct zcache_preload *kp; |
| |
| switch (action) { |
| case CPU_UP_PREPARE: |
| ret = zcache_comp_cpu_up(cpu); |
| if (ret != NOTIFY_OK) { |
| pr_err("zcache: can't allocate compressor transform\n"); |
| return ret; |
| } |
| per_cpu(zcache_dstmem, cpu) = (void *)__get_free_pages( |
| GFP_KERNEL | __GFP_REPEAT, ZCACHE_DSTMEM_ORDER); |
| break; |
| case CPU_DEAD: |
| case CPU_UP_CANCELED: |
| zcache_comp_cpu_down(cpu); |
| free_pages((unsigned long)per_cpu(zcache_dstmem, cpu), |
| ZCACHE_DSTMEM_ORDER); |
| per_cpu(zcache_dstmem, 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->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(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(zbpg_unused_list_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_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_failed_pers_puts_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_zbpg_unused_list_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", |
| }; |
| |
| #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 |
| */ |
| |
| static int zcache_put_page(int cli_id, int pool_id, struct tmem_oid *oidp, |
| uint32_t index, struct page *page) |
| { |
| 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, (char *)(page), |
| PAGE_SIZE, 0, is_ephemeral(pool)); |
| if (ret < 0) { |
| if (is_ephemeral(pool)) |
| zcache_failed_eph_puts++; |
| else |
| zcache_failed_pers_puts++; |
| } |
| } 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; |
| } |
| |
| static int zcache_get_page(int cli_id, int pool_id, struct tmem_oid *oidp, |
| uint32_t index, struct page *page) |
| { |
| struct tmem_pool *pool; |
| int ret = -1; |
| unsigned long flags; |
| size_t size = PAGE_SIZE; |
| |
| local_irq_save(flags); |
| pool = zcache_get_pool_by_id(cli_id, pool_id); |
| if (likely(pool != NULL)) { |
| if (atomic_read(&pool->obj_count) > 0) |
| ret = tmem_get(pool, oidp, index, (char *)(page), |
| &size, 0, is_ephemeral(pool)); |
| zcache_put_pool(pool); |
| } |
| local_irq_restore(flags); |
| return ret; |
| } |
| |
| static int zcache_flush_page(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); |
| 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; |
| } |
| |
| static 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); |
| 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; |
| } |
| |
| static int zcache_destroy_pool(int cli_id, int pool_id) |
| { |
| struct tmem_pool *pool = NULL; |
| struct zcache_client *cli; |
| int ret = -1; |
| |
| if (pool_id < 0) |
| goto out; |
| |
| cli = get_zcache_client(cli_id); |
| if (cli == NULL) |
| goto out; |
| |
| atomic_inc(&cli->refcount); |
| pool = idr_find(&cli->tmem_pools, pool_id); |
| if (pool == NULL) |
| goto out; |
| idr_remove(&cli->tmem_pools, pool_id); |
| /* 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("zcache: destroyed pool id=%d, cli_id=%d\n", |
| pool_id, cli_id); |
| out: |
| return ret; |
| } |
| |
| static int zcache_new_pool(uint16_t cli_id, uint32_t flags) |
| { |
| int poolid = -1; |
| struct tmem_pool *pool; |
| struct zcache_client *cli = NULL; |
| int r; |
| |
| cli = get_zcache_client(cli_id); |
| if (cli == NULL) |
| goto out; |
| |
| atomic_inc(&cli->refcount); |
| pool = kmalloc(sizeof(struct tmem_pool), GFP_ATOMIC); |
| if (pool == NULL) { |
| pr_info("zcache: pool creation failed: out of memory\n"); |
| goto out; |
| } |
| |
| do { |
| r = idr_pre_get(&cli->tmem_pools, GFP_ATOMIC); |
| if (r != 1) { |
| kfree(pool); |
| pr_info("zcache: pool creation failed: out of memory\n"); |
| goto out; |
| } |
| r = idr_get_new(&cli->tmem_pools, pool, &poolid); |
| } while (r == -EAGAIN); |
| if (r) { |
| pr_info("zcache: pool creation failed: error %d\n", r); |
| kfree(pool); |
| goto out; |
| } |
| |
| atomic_set(&pool->refcount, 0); |
| pool->client = cli; |
| pool->pool_id = poolid; |
| tmem_new_pool(pool, flags); |
| pr_info("zcache: 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; |
| } |
| |
| /********** |
| * 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; |
| |
| if (likely(ind == index)) |
| (void)zcache_put_page(LOCAL_CLIENT, pool_id, &oid, index, page); |
| } |
| |
| 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; |
| |
| if (likely(ind == index)) |
| ret = zcache_get_page(LOCAL_CLIENT, pool_id, &oid, index, page); |
| 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_page(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(LOCAL_CLIENT, 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_new_pool(LOCAL_CLIENT, 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_new_pool(LOCAL_CLIENT, 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 |
| * Setting SWIZ_BITS to 27 basically reconstructs the swap entry from |
| * frontswap_load(), but has side-effects. Hence using 8. |
| */ |
| #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; |
| |
| BUG_ON(!PageLocked(page)); |
| if (likely(ind64 == ind)) { |
| local_irq_save(flags); |
| ret = zcache_put_page(LOCAL_CLIENT, zcache_frontswap_poolid, |
| &oid, iswiz(ind), page); |
| 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; |
| |
| BUG_ON(!PageLocked(page)); |
| if (likely(ind64 == ind)) |
| ret = zcache_get_page(LOCAL_CLIENT, zcache_frontswap_poolid, |
| &oid, iswiz(ind), page); |
| 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_page(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_new_pool(LOCAL_CLIENT, 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 |
| |
| /* |
| * zcache initialization |
| * NOTE FOR NOW zcache MUST BE PROVIDED AS A KERNEL BOOT PARAMETER OR |
| * NOTHING HAPPENS! |
| */ |
| |
| static int zcache_enabled; |
| |
| static int __init enable_zcache(char *s) |
| { |
| zcache_enabled = 1; |
| return 1; |
| } |
| __setup("zcache", enable_zcache); |
| |
| /* allow independent dynamic disabling of cleancache and frontswap */ |
| |
| static int use_cleancache = 1; |
| |
| static int __init no_cleancache(char *s) |
| { |
| use_cleancache = 0; |
| return 1; |
| } |
| |
| __setup("nocleancache", no_cleancache); |
| |
| static int use_frontswap = 1; |
| |
| static int __init no_frontswap(char *s) |
| { |
| use_frontswap = 0; |
| return 1; |
| } |
| |
| __setup("nofrontswap", no_frontswap); |
| |
| static int __init enable_zcache_compressor(char *s) |
| { |
| strncpy(zcache_comp_name, s, ZCACHE_COMP_NAME_SZ); |
| zcache_enabled = 1; |
| return 1; |
| } |
| __setup("zcache=", enable_zcache_compressor); |
| |
| |
| static int __init zcache_comp_init(void) |
| { |
| int ret = 0; |
| |
| /* check crypto algorithm */ |
| if (*zcache_comp_name != '\0') { |
| ret = crypto_has_comp(zcache_comp_name, 0, 0); |
| if (!ret) |
| pr_info("zcache: %s not supported\n", |
| zcache_comp_name); |
| } |
| if (!ret) |
| strcpy(zcache_comp_name, "lzo"); |
| ret = crypto_has_comp(zcache_comp_name, 0, 0); |
| if (!ret) { |
| ret = 1; |
| goto out; |
| } |
| pr_info("zcache: using %s compressor\n", zcache_comp_name); |
| |
| /* alloc percpu transforms */ |
| ret = 0; |
| zcache_comp_pcpu_tfms = alloc_percpu(struct crypto_comp *); |
| if (!zcache_comp_pcpu_tfms) |
| ret = 1; |
| out: |
| return ret; |
| } |
| |
| static int __init zcache_init(void) |
| { |
| int ret = 0; |
| |
| #ifdef CONFIG_SYSFS |
| ret = sysfs_create_group(mm_kobj, &zcache_attr_group); |
| if (ret) { |
| pr_err("zcache: can't create sysfs\n"); |
| goto out; |
| } |
| #endif /* CONFIG_SYSFS */ |
| |
| if (zcache_enabled) { |
| unsigned int cpu; |
| |
| tmem_register_hostops(&zcache_hostops); |
| tmem_register_pamops(&zcache_pamops); |
| ret = register_cpu_notifier(&zcache_cpu_notifier_block); |
| if (ret) { |
| pr_err("zcache: can't register cpu notifier\n"); |
| goto out; |
| } |
| ret = zcache_comp_init(); |
| if (ret) { |
| pr_err("zcache: compressor initialization failed\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); |
| ret = zcache_new_client(LOCAL_CLIENT); |
| if (ret) { |
| pr_err("zcache: can't create client\n"); |
| goto out; |
| } |
| |
| #ifdef CONFIG_CLEANCACHE |
| if (zcache_enabled && use_cleancache) { |
| struct cleancache_ops old_ops; |
| |
| zbud_init(); |
| register_shrinker(&zcache_shrinker); |
| old_ops = zcache_cleancache_register_ops(); |
| pr_info("zcache: cleancache enabled using kernel " |
| "transcendent memory and compression buddies\n"); |
| if (old_ops.init_fs != NULL) |
| pr_warning("zcache: cleancache_ops overridden"); |
| } |
| #endif |
| #ifdef CONFIG_FRONTSWAP |
| if (zcache_enabled && use_frontswap) { |
| struct frontswap_ops old_ops; |
| |
| old_ops = zcache_frontswap_register_ops(); |
| pr_info("zcache: frontswap enabled using kernel " |
| "transcendent memory and zsmalloc\n"); |
| if (old_ops.init != NULL) |
| pr_warning("zcache: frontswap_ops overridden"); |
| } |
| #endif |
| out: |
| return ret; |
| } |
| |
| module_init(zcache_init) |