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mm/zswap.c
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/* * zswap.c - zswap driver file * * zswap is a backend for frontswap that takes pages that are in the process * of being swapped out and attempts to compress and store them in a * RAM-based memory pool. This can result in a significant I/O reduction on * the swap device and, in the case where decompressing from RAM is faster * than reading from the swap device, can also improve workload performance. * * Copyright (C) 2012 Seth Jennings <sjenning@linux.vnet.ibm.com> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/module.h> #include <linux/cpu.h> #include <linux/highmem.h> #include <linux/slab.h> #include <linux/spinlock.h> #include <linux/types.h> #include <linux/atomic.h> #include <linux/frontswap.h> #include <linux/rbtree.h> #include <linux/swap.h> #include <linux/crypto.h> #include <linux/mempool.h> |
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#include <linux/zpool.h> |
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#include <linux/mm_types.h> #include <linux/page-flags.h> #include <linux/swapops.h> #include <linux/writeback.h> #include <linux/pagemap.h> /********************************* * statistics **********************************/ |
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/* Total bytes used by the compressed storage */ static u64 zswap_pool_total_size; |
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/* The number of compressed pages currently stored in zswap */ static atomic_t zswap_stored_pages = ATOMIC_INIT(0); /* * The statistics below are not protected from concurrent access for * performance reasons so they may not be a 100% accurate. However, * they do provide useful information on roughly how many times a * certain event is occurring. */ /* Pool limit was hit (see zswap_max_pool_percent) */ static u64 zswap_pool_limit_hit; /* Pages written back when pool limit was reached */ static u64 zswap_written_back_pages; /* Store failed due to a reclaim failure after pool limit was reached */ static u64 zswap_reject_reclaim_fail; /* Compressed page was too big for the allocator to (optimally) store */ static u64 zswap_reject_compress_poor; /* Store failed because underlying allocator could not get memory */ static u64 zswap_reject_alloc_fail; /* Store failed because the entry metadata could not be allocated (rare) */ static u64 zswap_reject_kmemcache_fail; /* Duplicate store was encountered (rare) */ static u64 zswap_duplicate_entry; /********************************* * tunables **********************************/ |
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/* Enable/disable zswap (disabled by default) */ static bool zswap_enabled; |
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static int zswap_enabled_param_set(const char *, const struct kernel_param *); static struct kernel_param_ops zswap_enabled_param_ops = { .set = zswap_enabled_param_set, .get = param_get_bool, }; module_param_cb(enabled, &zswap_enabled_param_ops, &zswap_enabled, 0644); |
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/* Crypto compressor to use */ |
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#define ZSWAP_COMPRESSOR_DEFAULT "lzo" |
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static char *zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT; |
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static int zswap_compressor_param_set(const char *, const struct kernel_param *); static struct kernel_param_ops zswap_compressor_param_ops = { .set = zswap_compressor_param_set, |
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.get = param_get_charp, .free = param_free_charp, |
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}; module_param_cb(compressor, &zswap_compressor_param_ops, |
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&zswap_compressor, 0644); |
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|
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/* Compressed storage zpool to use */ |
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#define ZSWAP_ZPOOL_DEFAULT "zbud" |
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static char *zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT; |
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static int zswap_zpool_param_set(const char *, const struct kernel_param *); static struct kernel_param_ops zswap_zpool_param_ops = { |
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.set = zswap_zpool_param_set, .get = param_get_charp, .free = param_free_charp, |
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}; |
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module_param_cb(zpool, &zswap_zpool_param_ops, &zswap_zpool_type, 0644); |
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/* The maximum percentage of memory that the compressed pool can occupy */ static unsigned int zswap_max_pool_percent = 20; module_param_named(max_pool_percent, zswap_max_pool_percent, uint, 0644); |
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/********************************* |
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* data structures |
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**********************************/ |
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|
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struct zswap_pool { struct zpool *zpool; struct crypto_comp * __percpu *tfm; struct kref kref; struct list_head list; |
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struct work_struct work; |
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struct notifier_block notifier; char tfm_name[CRYPTO_MAX_ALG_NAME]; |
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}; |
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/* * struct zswap_entry * * This structure contains the metadata for tracking a single compressed * page within zswap. * * rbnode - links the entry into red-black tree for the appropriate swap type |
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* offset - the swap offset for the entry. Index into the red-black tree. |
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* refcount - the number of outstanding reference to the entry. This is needed * to protect against premature freeing of the entry by code |
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* concurrent calls to load, invalidate, and writeback. The lock |
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* for the zswap_tree structure that contains the entry must * be held while changing the refcount. Since the lock must * be held, there is no reason to also make refcount atomic. |
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* length - the length in bytes of the compressed page data. Needed during |
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* decompression |
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* pool - the zswap_pool the entry's data is in * handle - zpool allocation handle that stores the compressed page data |
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*/ struct zswap_entry { struct rb_node rbnode; pgoff_t offset; int refcount; unsigned int length; |
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struct zswap_pool *pool; |
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unsigned long handle; }; struct zswap_header { swp_entry_t swpentry; }; /* * The tree lock in the zswap_tree struct protects a few things: * - the rbtree * - the refcount field of each entry in the tree */ struct zswap_tree { struct rb_root rbroot; spinlock_t lock; |
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}; static struct zswap_tree *zswap_trees[MAX_SWAPFILES]; |
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/* RCU-protected iteration */ static LIST_HEAD(zswap_pools); /* protects zswap_pools list modification */ static DEFINE_SPINLOCK(zswap_pools_lock); |
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/* pool counter to provide unique names to zpool */ static atomic_t zswap_pools_count = ATOMIC_INIT(0); |
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/* used by param callback function */ static bool zswap_init_started; |
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/* fatal error during init */ static bool zswap_init_failed; |
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/********************************* * helpers and fwd declarations **********************************/ #define zswap_pool_debug(msg, p) \ pr_debug("%s pool %s/%s ", msg, (p)->tfm_name, \ zpool_get_type((p)->zpool)) static int zswap_writeback_entry(struct zpool *pool, unsigned long handle); static int zswap_pool_get(struct zswap_pool *pool); static void zswap_pool_put(struct zswap_pool *pool); static const struct zpool_ops zswap_zpool_ops = { .evict = zswap_writeback_entry }; static bool zswap_is_full(void) { return totalram_pages * zswap_max_pool_percent / 100 < DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE); } static void zswap_update_total_size(void) { struct zswap_pool *pool; u64 total = 0; rcu_read_lock(); list_for_each_entry_rcu(pool, &zswap_pools, list) total += zpool_get_total_size(pool->zpool); rcu_read_unlock(); zswap_pool_total_size = total; } |
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/********************************* * zswap entry functions **********************************/ static struct kmem_cache *zswap_entry_cache; |
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static int __init zswap_entry_cache_create(void) |
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{ zswap_entry_cache = KMEM_CACHE(zswap_entry, 0); |
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return zswap_entry_cache == NULL; |
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} |
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static void __init zswap_entry_cache_destroy(void) |
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{ kmem_cache_destroy(zswap_entry_cache); } static struct zswap_entry *zswap_entry_cache_alloc(gfp_t gfp) { struct zswap_entry *entry; entry = kmem_cache_alloc(zswap_entry_cache, gfp); if (!entry) return NULL; entry->refcount = 1; |
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RB_CLEAR_NODE(&entry->rbnode); |
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return entry; } static void zswap_entry_cache_free(struct zswap_entry *entry) { kmem_cache_free(zswap_entry_cache, entry); } |
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/********************************* * rbtree functions **********************************/ static struct zswap_entry *zswap_rb_search(struct rb_root *root, pgoff_t offset) { struct rb_node *node = root->rb_node; struct zswap_entry *entry; while (node) { entry = rb_entry(node, struct zswap_entry, rbnode); if (entry->offset > offset) node = node->rb_left; else if (entry->offset < offset) node = node->rb_right; else return entry; } return NULL; } /* * In the case that a entry with the same offset is found, a pointer to * the existing entry is stored in dupentry and the function returns -EEXIST */ static int zswap_rb_insert(struct rb_root *root, struct zswap_entry *entry, struct zswap_entry **dupentry) { struct rb_node **link = &root->rb_node, *parent = NULL; struct zswap_entry *myentry; while (*link) { parent = *link; myentry = rb_entry(parent, struct zswap_entry, rbnode); if (myentry->offset > entry->offset) link = &(*link)->rb_left; else if (myentry->offset < entry->offset) link = &(*link)->rb_right; else { *dupentry = myentry; return -EEXIST; } } rb_link_node(&entry->rbnode, parent, link); rb_insert_color(&entry->rbnode, root); return 0; } |
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static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry) { if (!RB_EMPTY_NODE(&entry->rbnode)) { rb_erase(&entry->rbnode, root); RB_CLEAR_NODE(&entry->rbnode); } } /* |
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* Carries out the common pattern of freeing and entry's zpool allocation, |
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* freeing the entry itself, and decrementing the number of stored pages. */ |
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static void zswap_free_entry(struct zswap_entry *entry) |
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{ |
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zpool_free(entry->pool->zpool, entry->handle); zswap_pool_put(entry->pool); |
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zswap_entry_cache_free(entry); atomic_dec(&zswap_stored_pages); |
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zswap_update_total_size(); |
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} /* caller must hold the tree lock */ static void zswap_entry_get(struct zswap_entry *entry) { entry->refcount++; } /* caller must hold the tree lock * remove from the tree and free it, if nobody reference the entry */ static void zswap_entry_put(struct zswap_tree *tree, struct zswap_entry *entry) { int refcount = --entry->refcount; BUG_ON(refcount < 0); if (refcount == 0) { zswap_rb_erase(&tree->rbroot, entry); |
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zswap_free_entry(entry); |
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} } /* caller must hold the tree lock */ static struct zswap_entry *zswap_entry_find_get(struct rb_root *root, pgoff_t offset) { |
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struct zswap_entry *entry; |
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entry = zswap_rb_search(root, offset); if (entry) zswap_entry_get(entry); return entry; } |
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/********************************* * per-cpu code **********************************/ static DEFINE_PER_CPU(u8 *, zswap_dstmem); |
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static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu) |
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{ |
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u8 *dst; switch (action) { case CPU_UP_PREPARE: |
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dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu)); |
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if (!dst) { pr_err("can't allocate compressor buffer "); |
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return NOTIFY_BAD; } per_cpu(zswap_dstmem, cpu) = dst; break; case CPU_DEAD: case CPU_UP_CANCELED: |
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dst = per_cpu(zswap_dstmem, cpu); kfree(dst); per_cpu(zswap_dstmem, cpu) = NULL; break; default: break; } return NOTIFY_OK; } |
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static int zswap_cpu_dstmem_notifier(struct notifier_block *nb, unsigned long action, void *pcpu) |
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{ |
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return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu); |
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} |
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static struct notifier_block zswap_dstmem_notifier = { .notifier_call = zswap_cpu_dstmem_notifier, |
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}; |
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static int __init zswap_cpu_dstmem_init(void) { unsigned long cpu; cpu_notifier_register_begin(); for_each_online_cpu(cpu) if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) == NOTIFY_BAD) goto cleanup; __register_cpu_notifier(&zswap_dstmem_notifier); cpu_notifier_register_done(); return 0; cleanup: for_each_online_cpu(cpu) __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu); cpu_notifier_register_done(); return -ENOMEM; } static void zswap_cpu_dstmem_destroy(void) { unsigned long cpu; cpu_notifier_register_begin(); for_each_online_cpu(cpu) __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu); __unregister_cpu_notifier(&zswap_dstmem_notifier); cpu_notifier_register_done(); } static int __zswap_cpu_comp_notifier(struct zswap_pool *pool, unsigned long action, unsigned long cpu) { struct crypto_comp *tfm; switch (action) { case CPU_UP_PREPARE: if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu))) break; tfm = crypto_alloc_comp(pool->tfm_name, 0, 0); if (IS_ERR_OR_NULL(tfm)) { pr_err("could not alloc crypto comp %s : %ld ", pool->tfm_name, PTR_ERR(tfm)); return NOTIFY_BAD; } *per_cpu_ptr(pool->tfm, cpu) = tfm; break; case CPU_DEAD: case CPU_UP_CANCELED: tfm = *per_cpu_ptr(pool->tfm, cpu); if (!IS_ERR_OR_NULL(tfm)) crypto_free_comp(tfm); *per_cpu_ptr(pool->tfm, cpu) = NULL; break; default: break; } return NOTIFY_OK; } static int zswap_cpu_comp_notifier(struct notifier_block *nb, unsigned long action, void *pcpu) { unsigned long cpu = (unsigned long)pcpu; struct zswap_pool *pool = container_of(nb, typeof(*pool), notifier); return __zswap_cpu_comp_notifier(pool, action, cpu); } static int zswap_cpu_comp_init(struct zswap_pool *pool) |
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{ unsigned long cpu; |
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memset(&pool->notifier, 0, sizeof(pool->notifier)); pool->notifier.notifier_call = zswap_cpu_comp_notifier; |
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cpu_notifier_register_begin(); |
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for_each_online_cpu(cpu) |
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if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) == NOTIFY_BAD) |
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goto cleanup; |
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__register_cpu_notifier(&pool->notifier); |
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cpu_notifier_register_done(); |
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return 0; cleanup: for_each_online_cpu(cpu) |
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__zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu); |
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cpu_notifier_register_done(); |
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return -ENOMEM; } |
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static void zswap_cpu_comp_destroy(struct zswap_pool *pool) { unsigned long cpu; cpu_notifier_register_begin(); for_each_online_cpu(cpu) __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu); __unregister_cpu_notifier(&pool->notifier); cpu_notifier_register_done(); } |
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/********************************* |
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* pool functions |
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**********************************/ |
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static struct zswap_pool *__zswap_pool_current(void) |
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{ |
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struct zswap_pool *pool; pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list); WARN_ON(!pool); return pool; } static struct zswap_pool *zswap_pool_current(void) { assert_spin_locked(&zswap_pools_lock); return __zswap_pool_current(); } static struct zswap_pool *zswap_pool_current_get(void) { struct zswap_pool *pool; rcu_read_lock(); pool = __zswap_pool_current(); if (!pool || !zswap_pool_get(pool)) pool = NULL; rcu_read_unlock(); return pool; } static struct zswap_pool *zswap_pool_last_get(void) { struct zswap_pool *pool, *last = NULL; rcu_read_lock(); list_for_each_entry_rcu(pool, &zswap_pools, list) last = pool; if (!WARN_ON(!last) && !zswap_pool_get(last)) last = NULL; rcu_read_unlock(); return last; } |
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/* type and compressor must be null-terminated */ |
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static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor) { struct zswap_pool *pool; assert_spin_locked(&zswap_pools_lock); list_for_each_entry_rcu(pool, &zswap_pools, list) { |
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if (strcmp(pool->tfm_name, compressor)) |
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continue; |
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if (strcmp(zpool_get_type(pool->zpool), type)) |
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continue; /* if we can't get it, it's about to be destroyed */ if (!zswap_pool_get(pool)) continue; return pool; } return NULL; } static struct zswap_pool *zswap_pool_create(char *type, char *compressor) { struct zswap_pool *pool; |
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char name[38]; /* 'zswap' + 32 char (max) num + \0 */ |
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gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM; |
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pool = kzalloc(sizeof(*pool), GFP_KERNEL); if (!pool) { pr_err("pool alloc failed "); return NULL; } |
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/* unique name for each pool specifically required by zsmalloc */ snprintf(name, 38, "zswap%x", atomic_inc_return(&zswap_pools_count)); pool->zpool = zpool_create_pool(type, name, gfp, &zswap_zpool_ops); |
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if (!pool->zpool) { pr_err("%s zpool not available ", type); goto error; } pr_debug("using %s zpool ", zpool_get_type(pool->zpool)); strlcpy(pool->tfm_name, compressor, sizeof(pool->tfm_name)); pool->tfm = alloc_percpu(struct crypto_comp *); if (!pool->tfm) { pr_err("percpu alloc failed "); goto error; } if (zswap_cpu_comp_init(pool)) goto error; pr_debug("using %s compressor ", pool->tfm_name); /* being the current pool takes 1 ref; this func expects the * caller to always add the new pool as the current pool */ kref_init(&pool->kref); INIT_LIST_HEAD(&pool->list); zswap_pool_debug("created", pool); return pool; error: free_percpu(pool->tfm); if (pool->zpool) zpool_destroy_pool(pool->zpool); kfree(pool); return NULL; } |
c99b42c35 zswap: use charp ... |
614 |
static __init struct zswap_pool *__zswap_pool_create_fallback(void) |
f1c54846e zswap: dynamic po... |
615 616 |
{ if (!crypto_has_comp(zswap_compressor, 0, 0)) { |
c99b42c35 zswap: use charp ... |
617 618 619 620 621 622 |
if (!strcmp(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT)) { pr_err("default compressor %s not available ", zswap_compressor); return NULL; } |
f1c54846e zswap: dynamic po... |
623 624 625 |
pr_err("compressor %s not available, using default %s ", zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT); |
c99b42c35 zswap: use charp ... |
626 627 |
param_free_charp(&zswap_compressor); zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT; |
f1c54846e zswap: dynamic po... |
628 629 |
} if (!zpool_has_pool(zswap_zpool_type)) { |
c99b42c35 zswap: use charp ... |
630 631 632 633 634 635 |
if (!strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) { pr_err("default zpool %s not available ", zswap_zpool_type); return NULL; } |
f1c54846e zswap: dynamic po... |
636 637 638 |
pr_err("zpool %s not available, using default %s ", zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT); |
c99b42c35 zswap: use charp ... |
639 640 |
param_free_charp(&zswap_zpool_type); zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT; |
f1c54846e zswap: dynamic po... |
641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 |
} return zswap_pool_create(zswap_zpool_type, zswap_compressor); } static void zswap_pool_destroy(struct zswap_pool *pool) { zswap_pool_debug("destroying", pool); zswap_cpu_comp_destroy(pool); free_percpu(pool->tfm); zpool_destroy_pool(pool->zpool); kfree(pool); } static int __must_check zswap_pool_get(struct zswap_pool *pool) { return kref_get_unless_zero(&pool->kref); } |
200867af4 mm/zswap: use wor... |
660 |
static void __zswap_pool_release(struct work_struct *work) |
f1c54846e zswap: dynamic po... |
661 |
{ |
200867af4 mm/zswap: use wor... |
662 663 664 |
struct zswap_pool *pool = container_of(work, typeof(*pool), work); synchronize_rcu(); |
f1c54846e zswap: dynamic po... |
665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 |
/* nobody should have been able to get a kref... */ WARN_ON(kref_get_unless_zero(&pool->kref)); /* pool is now off zswap_pools list and has no references. */ zswap_pool_destroy(pool); } static void __zswap_pool_empty(struct kref *kref) { struct zswap_pool *pool; pool = container_of(kref, typeof(*pool), kref); spin_lock(&zswap_pools_lock); WARN_ON(pool == zswap_pool_current()); list_del_rcu(&pool->list); |
200867af4 mm/zswap: use wor... |
684 685 686 |
INIT_WORK(&pool->work, __zswap_pool_release); schedule_work(&pool->work); |
f1c54846e zswap: dynamic po... |
687 688 689 690 691 692 693 |
spin_unlock(&zswap_pools_lock); } static void zswap_pool_put(struct zswap_pool *pool) { kref_put(&pool->kref, __zswap_pool_empty); |
2b2811178 zswap: add to mm/ |
694 |
} |
2b2811178 zswap: add to mm/ |
695 |
/********************************* |
90b0fc26d zswap: change zpo... |
696 697 |
* param callbacks **********************************/ |
c99b42c35 zswap: use charp ... |
698 |
/* val must be a null-terminated string */ |
90b0fc26d zswap: change zpo... |
699 700 701 702 |
static int __zswap_param_set(const char *val, const struct kernel_param *kp, char *type, char *compressor) { struct zswap_pool *pool, *put_pool = NULL; |
c99b42c35 zswap: use charp ... |
703 |
char *s = strstrip((char *)val); |
90b0fc26d zswap: change zpo... |
704 |
int ret; |
f0c3a0ac3 zswap: disable ch... |
705 706 707 708 709 |
if (zswap_init_failed) { pr_err("can't set param, initialization failed "); return -ENODEV; } |
c99b42c35 zswap: use charp ... |
710 711 712 |
/* no change required */ if (!strcmp(s, *(char **)kp->arg)) return 0; |
90b0fc26d zswap: change zpo... |
713 714 715 716 717 |
/* if this is load-time (pre-init) param setting, * don't create a pool; that's done during init. */ if (!zswap_init_started) |
c99b42c35 zswap: use charp ... |
718 |
return param_set_charp(s, kp); |
90b0fc26d zswap: change zpo... |
719 720 |
if (!type) { |
c99b42c35 zswap: use charp ... |
721 722 723 |
if (!zpool_has_pool(s)) { pr_err("zpool %s not available ", s); |
90b0fc26d zswap: change zpo... |
724 725 |
return -ENOENT; } |
c99b42c35 zswap: use charp ... |
726 |
type = s; |
90b0fc26d zswap: change zpo... |
727 |
} else if (!compressor) { |
c99b42c35 zswap: use charp ... |
728 729 730 |
if (!crypto_has_comp(s, 0, 0)) { pr_err("compressor %s not available ", s); |
90b0fc26d zswap: change zpo... |
731 732 |
return -ENOENT; } |
c99b42c35 zswap: use charp ... |
733 734 735 736 |
compressor = s; } else { WARN_ON(1); return -EINVAL; |
90b0fc26d zswap: change zpo... |
737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 |
} spin_lock(&zswap_pools_lock); pool = zswap_pool_find_get(type, compressor); if (pool) { zswap_pool_debug("using existing", pool); list_del_rcu(&pool->list); } else { spin_unlock(&zswap_pools_lock); pool = zswap_pool_create(type, compressor); spin_lock(&zswap_pools_lock); } if (pool) |
c99b42c35 zswap: use charp ... |
752 |
ret = param_set_charp(s, kp); |
90b0fc26d zswap: change zpo... |
753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 |
else ret = -EINVAL; if (!ret) { put_pool = zswap_pool_current(); list_add_rcu(&pool->list, &zswap_pools); } else if (pool) { /* add the possibly pre-existing pool to the end of the pools * list; if it's new (and empty) then it'll be removed and * destroyed by the put after we drop the lock */ list_add_tail_rcu(&pool->list, &zswap_pools); put_pool = pool; } spin_unlock(&zswap_pools_lock); /* drop the ref from either the old current pool, * or the new pool we failed to add */ if (put_pool) zswap_pool_put(put_pool); return ret; } static int zswap_compressor_param_set(const char *val, const struct kernel_param *kp) { return __zswap_param_set(val, kp, zswap_zpool_type, NULL); } static int zswap_zpool_param_set(const char *val, const struct kernel_param *kp) { return __zswap_param_set(val, kp, NULL, zswap_compressor); } |
f0c3a0ac3 zswap: disable ch... |
790 791 792 793 794 795 796 797 798 799 800 |
static int zswap_enabled_param_set(const char *val, const struct kernel_param *kp) { if (zswap_init_failed) { pr_err("can't enable, initialization failed "); return -ENODEV; } return param_set_bool(val, kp); } |
90b0fc26d zswap: change zpo... |
801 |
/********************************* |
2b2811178 zswap: add to mm/ |
802 803 804 805 806 807 |
* writeback code **********************************/ /* return enum for zswap_get_swap_cache_page */ enum zswap_get_swap_ret { ZSWAP_SWAPCACHE_NEW, ZSWAP_SWAPCACHE_EXIST, |
67d13fe84 mm/zswap: bugfix:... |
808 |
ZSWAP_SWAPCACHE_FAIL, |
2b2811178 zswap: add to mm/ |
809 810 811 812 813 814 815 816 817 818 819 820 821 |
}; /* * zswap_get_swap_cache_page * * This is an adaption of read_swap_cache_async() * * This function tries to find a page with the given swap entry * in the swapper_space address space (the swap cache). If the page * is found, it is returned in retpage. Otherwise, a page is allocated, * added to the swap cache, and returned in retpage. * * If success, the swap cache page is returned in retpage |
67d13fe84 mm/zswap: bugfix:... |
822 823 824 825 |
* Returns ZSWAP_SWAPCACHE_EXIST if page was already in the swap cache * Returns ZSWAP_SWAPCACHE_NEW if the new page needs to be populated, * the new page is added to swapcache and locked * Returns ZSWAP_SWAPCACHE_FAIL on error |
2b2811178 zswap: add to mm/ |
826 827 828 829 |
*/ static int zswap_get_swap_cache_page(swp_entry_t entry, struct page **retpage) { |
5b999aadb mm: swap: zswap: ... |
830 |
bool page_was_allocated; |
2b2811178 zswap: add to mm/ |
831 |
|
5b999aadb mm: swap: zswap: ... |
832 833 834 835 836 |
*retpage = __read_swap_cache_async(entry, GFP_KERNEL, NULL, 0, &page_was_allocated); if (page_was_allocated) return ZSWAP_SWAPCACHE_NEW; if (!*retpage) |
67d13fe84 mm/zswap: bugfix:... |
837 |
return ZSWAP_SWAPCACHE_FAIL; |
2b2811178 zswap: add to mm/ |
838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 |
return ZSWAP_SWAPCACHE_EXIST; } /* * Attempts to free an entry by adding a page to the swap cache, * decompressing the entry data into the page, and issuing a * bio write to write the page back to the swap device. * * This can be thought of as a "resumed writeback" of the page * to the swap device. We are basically resuming the same swap * writeback path that was intercepted with the frontswap_store() * in the first place. After the page has been decompressed into * the swap cache, the compressed version stored by zswap can be * freed. */ |
12d79d64b mm/zpool: update ... |
853 |
static int zswap_writeback_entry(struct zpool *pool, unsigned long handle) |
2b2811178 zswap: add to mm/ |
854 855 856 857 858 859 860 |
{ struct zswap_header *zhdr; swp_entry_t swpentry; struct zswap_tree *tree; pgoff_t offset; struct zswap_entry *entry; struct page *page; |
f1c54846e zswap: dynamic po... |
861 |
struct crypto_comp *tfm; |
2b2811178 zswap: add to mm/ |
862 863 |
u8 *src, *dst; unsigned int dlen; |
0ab0abcf5 mm/zswap: refacto... |
864 |
int ret; |
2b2811178 zswap: add to mm/ |
865 866 867 868 869 |
struct writeback_control wbc = { .sync_mode = WB_SYNC_NONE, }; /* extract swpentry from data */ |
12d79d64b mm/zpool: update ... |
870 |
zhdr = zpool_map_handle(pool, handle, ZPOOL_MM_RO); |
2b2811178 zswap: add to mm/ |
871 |
swpentry = zhdr->swpentry; /* here */ |
12d79d64b mm/zpool: update ... |
872 |
zpool_unmap_handle(pool, handle); |
2b2811178 zswap: add to mm/ |
873 874 |
tree = zswap_trees[swp_type(swpentry)]; offset = swp_offset(swpentry); |
2b2811178 zswap: add to mm/ |
875 876 877 |
/* find and ref zswap entry */ spin_lock(&tree->lock); |
0ab0abcf5 mm/zswap: refacto... |
878 |
entry = zswap_entry_find_get(&tree->rbroot, offset); |
2b2811178 zswap: add to mm/ |
879 880 881 882 883 |
if (!entry) { /* entry was invalidated */ spin_unlock(&tree->lock); return 0; } |
2b2811178 zswap: add to mm/ |
884 885 886 887 888 |
spin_unlock(&tree->lock); BUG_ON(offset != entry->offset); /* try to allocate swap cache page */ switch (zswap_get_swap_cache_page(swpentry, &page)) { |
67d13fe84 mm/zswap: bugfix:... |
889 |
case ZSWAP_SWAPCACHE_FAIL: /* no memory or invalidate happened */ |
2b2811178 zswap: add to mm/ |
890 891 |
ret = -ENOMEM; goto fail; |
67d13fe84 mm/zswap: bugfix:... |
892 |
case ZSWAP_SWAPCACHE_EXIST: |
2b2811178 zswap: add to mm/ |
893 |
/* page is already in the swap cache, ignore for now */ |
09cbfeaf1 mm, fs: get rid o... |
894 |
put_page(page); |
2b2811178 zswap: add to mm/ |
895 896 897 898 899 900 |
ret = -EEXIST; goto fail; case ZSWAP_SWAPCACHE_NEW: /* page is locked */ /* decompress */ dlen = PAGE_SIZE; |
f1c54846e zswap: dynamic po... |
901 |
src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle, |
12d79d64b mm/zpool: update ... |
902 |
ZPOOL_MM_RO) + sizeof(struct zswap_header); |
2b2811178 zswap: add to mm/ |
903 |
dst = kmap_atomic(page); |
f1c54846e zswap: dynamic po... |
904 905 906 907 |
tfm = *get_cpu_ptr(entry->pool->tfm); ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen); put_cpu_ptr(entry->pool->tfm); |
2b2811178 zswap: add to mm/ |
908 |
kunmap_atomic(dst); |
f1c54846e zswap: dynamic po... |
909 |
zpool_unmap_handle(entry->pool->zpool, entry->handle); |
2b2811178 zswap: add to mm/ |
910 911 912 913 914 915 |
BUG_ON(ret); BUG_ON(dlen != PAGE_SIZE); /* page is up to date */ SetPageUptodate(page); } |
b349acc76 mm/zswap: avoid u... |
916 917 |
/* move it to the tail of the inactive list after end_writeback */ SetPageReclaim(page); |
2b2811178 zswap: add to mm/ |
918 919 |
/* start writeback */ __swap_writepage(page, &wbc, end_swap_bio_write); |
09cbfeaf1 mm, fs: get rid o... |
920 |
put_page(page); |
2b2811178 zswap: add to mm/ |
921 922 923 |
zswap_written_back_pages++; spin_lock(&tree->lock); |
2b2811178 zswap: add to mm/ |
924 |
/* drop local reference */ |
0ab0abcf5 mm/zswap: refacto... |
925 |
zswap_entry_put(tree, entry); |
2b2811178 zswap: add to mm/ |
926 927 |
/* |
0ab0abcf5 mm/zswap: refacto... |
928 929 930 931 932 933 934 935 |
* There are two possible situations for entry here: * (1) refcount is 1(normal case), entry is valid and on the tree * (2) refcount is 0, entry is freed and not on the tree * because invalidate happened during writeback * search the tree and free the entry if find entry */ if (entry == zswap_rb_search(&tree->rbroot, offset)) zswap_entry_put(tree, entry); |
2b2811178 zswap: add to mm/ |
936 |
spin_unlock(&tree->lock); |
2b2811178 zswap: add to mm/ |
937 |
|
0ab0abcf5 mm/zswap: refacto... |
938 939 940 941 942 943 944 945 946 |
goto end; /* * if we get here due to ZSWAP_SWAPCACHE_EXIST * a load may happening concurrently * it is safe and okay to not free the entry * if we free the entry in the following put * it it either okay to return !0 */ |
2b2811178 zswap: add to mm/ |
947 948 |
fail: spin_lock(&tree->lock); |
0ab0abcf5 mm/zswap: refacto... |
949 |
zswap_entry_put(tree, entry); |
2b2811178 zswap: add to mm/ |
950 |
spin_unlock(&tree->lock); |
0ab0abcf5 mm/zswap: refacto... |
951 952 |
end: |
2b2811178 zswap: add to mm/ |
953 954 |
return ret; } |
f1c54846e zswap: dynamic po... |
955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 |
static int zswap_shrink(void) { struct zswap_pool *pool; int ret; pool = zswap_pool_last_get(); if (!pool) return -ENOENT; ret = zpool_shrink(pool->zpool, 1, NULL); zswap_pool_put(pool); return ret; } |
2b2811178 zswap: add to mm/ |
970 971 972 973 974 975 976 977 978 |
/********************************* * frontswap hooks **********************************/ /* attempts to compress and store an single page */ static int zswap_frontswap_store(unsigned type, pgoff_t offset, struct page *page) { struct zswap_tree *tree = zswap_trees[type]; struct zswap_entry *entry, *dupentry; |
f1c54846e zswap: dynamic po... |
979 |
struct crypto_comp *tfm; |
2b2811178 zswap: add to mm/ |
980 981 982 983 984 985 |
int ret; unsigned int dlen = PAGE_SIZE, len; unsigned long handle; char *buf; u8 *src, *dst; struct zswap_header *zhdr; |
c00ed16a9 zswap: runtime en... |
986 |
if (!zswap_enabled || !tree) { |
2b2811178 zswap: add to mm/ |
987 988 989 990 991 992 993 |
ret = -ENODEV; goto reject; } /* reclaim space if needed */ if (zswap_is_full()) { zswap_pool_limit_hit++; |
f1c54846e zswap: dynamic po... |
994 |
if (zswap_shrink()) { |
2b2811178 zswap: add to mm/ |
995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 |
zswap_reject_reclaim_fail++; ret = -ENOMEM; goto reject; } } /* allocate entry */ entry = zswap_entry_cache_alloc(GFP_KERNEL); if (!entry) { zswap_reject_kmemcache_fail++; ret = -ENOMEM; goto reject; } |
f1c54846e zswap: dynamic po... |
1008 1009 1010 1011 1012 1013 |
/* if entry is successfully added, it keeps the reference */ entry->pool = zswap_pool_current_get(); if (!entry->pool) { ret = -EINVAL; goto freepage; } |
2b2811178 zswap: add to mm/ |
1014 1015 |
/* compress */ dst = get_cpu_var(zswap_dstmem); |
f1c54846e zswap: dynamic po... |
1016 |
tfm = *get_cpu_ptr(entry->pool->tfm); |
2b2811178 zswap: add to mm/ |
1017 |
src = kmap_atomic(page); |
f1c54846e zswap: dynamic po... |
1018 |
ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen); |
2b2811178 zswap: add to mm/ |
1019 |
kunmap_atomic(src); |
f1c54846e zswap: dynamic po... |
1020 |
put_cpu_ptr(entry->pool->tfm); |
2b2811178 zswap: add to mm/ |
1021 1022 |
if (ret) { ret = -EINVAL; |
f1c54846e zswap: dynamic po... |
1023 |
goto put_dstmem; |
2b2811178 zswap: add to mm/ |
1024 1025 1026 1027 |
} /* store */ len = dlen + sizeof(struct zswap_header); |
f1c54846e zswap: dynamic po... |
1028 |
ret = zpool_malloc(entry->pool->zpool, len, |
d0164adc8 mm, page_alloc: d... |
1029 1030 |
__GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM, &handle); |
2b2811178 zswap: add to mm/ |
1031 1032 |
if (ret == -ENOSPC) { zswap_reject_compress_poor++; |
f1c54846e zswap: dynamic po... |
1033 |
goto put_dstmem; |
2b2811178 zswap: add to mm/ |
1034 1035 1036 |
} if (ret) { zswap_reject_alloc_fail++; |
f1c54846e zswap: dynamic po... |
1037 |
goto put_dstmem; |
2b2811178 zswap: add to mm/ |
1038 |
} |
f1c54846e zswap: dynamic po... |
1039 |
zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW); |
2b2811178 zswap: add to mm/ |
1040 1041 1042 |
zhdr->swpentry = swp_entry(type, offset); buf = (u8 *)(zhdr + 1); memcpy(buf, dst, dlen); |
f1c54846e zswap: dynamic po... |
1043 |
zpool_unmap_handle(entry->pool->zpool, handle); |
2b2811178 zswap: add to mm/ |
1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 |
put_cpu_var(zswap_dstmem); /* populate entry */ entry->offset = offset; entry->handle = handle; entry->length = dlen; /* map */ spin_lock(&tree->lock); do { ret = zswap_rb_insert(&tree->rbroot, entry, &dupentry); if (ret == -EEXIST) { zswap_duplicate_entry++; /* remove from rbtree */ |
0ab0abcf5 mm/zswap: refacto... |
1058 1059 |
zswap_rb_erase(&tree->rbroot, dupentry); zswap_entry_put(tree, dupentry); |
2b2811178 zswap: add to mm/ |
1060 1061 1062 1063 1064 1065 |
} } while (ret == -EEXIST); spin_unlock(&tree->lock); /* update stats */ atomic_inc(&zswap_stored_pages); |
f1c54846e zswap: dynamic po... |
1066 |
zswap_update_total_size(); |
2b2811178 zswap: add to mm/ |
1067 1068 |
return 0; |
f1c54846e zswap: dynamic po... |
1069 |
put_dstmem: |
2b2811178 zswap: add to mm/ |
1070 |
put_cpu_var(zswap_dstmem); |
f1c54846e zswap: dynamic po... |
1071 1072 |
zswap_pool_put(entry->pool); freepage: |
2b2811178 zswap: add to mm/ |
1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 |
zswap_entry_cache_free(entry); reject: return ret; } /* * returns 0 if the page was successfully decompressed * return -1 on entry not found or error */ static int zswap_frontswap_load(unsigned type, pgoff_t offset, struct page *page) { struct zswap_tree *tree = zswap_trees[type]; struct zswap_entry *entry; |
f1c54846e zswap: dynamic po... |
1087 |
struct crypto_comp *tfm; |
2b2811178 zswap: add to mm/ |
1088 1089 |
u8 *src, *dst; unsigned int dlen; |
0ab0abcf5 mm/zswap: refacto... |
1090 |
int ret; |
2b2811178 zswap: add to mm/ |
1091 1092 1093 |
/* find */ spin_lock(&tree->lock); |
0ab0abcf5 mm/zswap: refacto... |
1094 |
entry = zswap_entry_find_get(&tree->rbroot, offset); |
2b2811178 zswap: add to mm/ |
1095 1096 1097 1098 1099 |
if (!entry) { /* entry was written back */ spin_unlock(&tree->lock); return -1; } |
2b2811178 zswap: add to mm/ |
1100 1101 1102 1103 |
spin_unlock(&tree->lock); /* decompress */ dlen = PAGE_SIZE; |
f1c54846e zswap: dynamic po... |
1104 |
src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle, |
12d79d64b mm/zpool: update ... |
1105 |
ZPOOL_MM_RO) + sizeof(struct zswap_header); |
2b2811178 zswap: add to mm/ |
1106 |
dst = kmap_atomic(page); |
f1c54846e zswap: dynamic po... |
1107 1108 1109 |
tfm = *get_cpu_ptr(entry->pool->tfm); ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen); put_cpu_ptr(entry->pool->tfm); |
2b2811178 zswap: add to mm/ |
1110 |
kunmap_atomic(dst); |
f1c54846e zswap: dynamic po... |
1111 |
zpool_unmap_handle(entry->pool->zpool, entry->handle); |
2b2811178 zswap: add to mm/ |
1112 1113 1114 |
BUG_ON(ret); spin_lock(&tree->lock); |
0ab0abcf5 mm/zswap: refacto... |
1115 |
zswap_entry_put(tree, entry); |
2b2811178 zswap: add to mm/ |
1116 |
spin_unlock(&tree->lock); |
2b2811178 zswap: add to mm/ |
1117 1118 1119 1120 1121 1122 1123 1124 |
return 0; } /* frees an entry in zswap */ static void zswap_frontswap_invalidate_page(unsigned type, pgoff_t offset) { struct zswap_tree *tree = zswap_trees[type]; struct zswap_entry *entry; |
2b2811178 zswap: add to mm/ |
1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 |
/* find */ spin_lock(&tree->lock); entry = zswap_rb_search(&tree->rbroot, offset); if (!entry) { /* entry was written back */ spin_unlock(&tree->lock); return; } /* remove from rbtree */ |
0ab0abcf5 mm/zswap: refacto... |
1136 |
zswap_rb_erase(&tree->rbroot, entry); |
2b2811178 zswap: add to mm/ |
1137 1138 |
/* drop the initial reference from entry creation */ |
0ab0abcf5 mm/zswap: refacto... |
1139 |
zswap_entry_put(tree, entry); |
2b2811178 zswap: add to mm/ |
1140 1141 |
spin_unlock(&tree->lock); |
2b2811178 zswap: add to mm/ |
1142 1143 1144 1145 1146 1147 |
} /* frees all zswap entries for the given swap type */ static void zswap_frontswap_invalidate_area(unsigned type) { struct zswap_tree *tree = zswap_trees[type]; |
0bd42136f mm/zswap: use pos... |
1148 |
struct zswap_entry *entry, *n; |
2b2811178 zswap: add to mm/ |
1149 1150 1151 1152 1153 1154 |
if (!tree) return; /* walk the tree and free everything */ spin_lock(&tree->lock); |
0ab0abcf5 mm/zswap: refacto... |
1155 |
rbtree_postorder_for_each_entry_safe(entry, n, &tree->rbroot, rbnode) |
60105e124 mm/zswap: support... |
1156 |
zswap_free_entry(entry); |
2b2811178 zswap: add to mm/ |
1157 1158 |
tree->rbroot = RB_ROOT; spin_unlock(&tree->lock); |
aa9bca05a mm/zswap: bugfix:... |
1159 1160 |
kfree(tree); zswap_trees[type] = NULL; |
2b2811178 zswap: add to mm/ |
1161 |
} |
2b2811178 zswap: add to mm/ |
1162 1163 1164 1165 1166 |
static void zswap_frontswap_init(unsigned type) { struct zswap_tree *tree; tree = kzalloc(sizeof(struct zswap_tree), GFP_KERNEL); |
60105e124 mm/zswap: support... |
1167 1168 1169 1170 1171 |
if (!tree) { pr_err("alloc failed, zswap disabled for swap type %d ", type); return; } |
2b2811178 zswap: add to mm/ |
1172 1173 1174 |
tree->rbroot = RB_ROOT; spin_lock_init(&tree->lock); zswap_trees[type] = tree; |
2b2811178 zswap: add to mm/ |
1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 |
} static struct frontswap_ops zswap_frontswap_ops = { .store = zswap_frontswap_store, .load = zswap_frontswap_load, .invalidate_page = zswap_frontswap_invalidate_page, .invalidate_area = zswap_frontswap_invalidate_area, .init = zswap_frontswap_init }; /********************************* * debugfs functions **********************************/ #ifdef CONFIG_DEBUG_FS #include <linux/debugfs.h> static struct dentry *zswap_debugfs_root; static int __init zswap_debugfs_init(void) { if (!debugfs_initialized()) return -ENODEV; zswap_debugfs_root = debugfs_create_dir("zswap", NULL); if (!zswap_debugfs_root) return -ENOMEM; debugfs_create_u64("pool_limit_hit", S_IRUGO, zswap_debugfs_root, &zswap_pool_limit_hit); debugfs_create_u64("reject_reclaim_fail", S_IRUGO, zswap_debugfs_root, &zswap_reject_reclaim_fail); debugfs_create_u64("reject_alloc_fail", S_IRUGO, zswap_debugfs_root, &zswap_reject_alloc_fail); debugfs_create_u64("reject_kmemcache_fail", S_IRUGO, zswap_debugfs_root, &zswap_reject_kmemcache_fail); debugfs_create_u64("reject_compress_poor", S_IRUGO, zswap_debugfs_root, &zswap_reject_compress_poor); debugfs_create_u64("written_back_pages", S_IRUGO, zswap_debugfs_root, &zswap_written_back_pages); debugfs_create_u64("duplicate_entry", S_IRUGO, zswap_debugfs_root, &zswap_duplicate_entry); |
12d79d64b mm/zpool: update ... |
1216 1217 |
debugfs_create_u64("pool_total_size", S_IRUGO, zswap_debugfs_root, &zswap_pool_total_size); |
2b2811178 zswap: add to mm/ |
1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 |
debugfs_create_atomic_t("stored_pages", S_IRUGO, zswap_debugfs_root, &zswap_stored_pages); return 0; } static void __exit zswap_debugfs_exit(void) { debugfs_remove_recursive(zswap_debugfs_root); } #else static int __init zswap_debugfs_init(void) { return 0; } static void __exit zswap_debugfs_exit(void) { } #endif /********************************* * module init and exit **********************************/ static int __init init_zswap(void) { |
f1c54846e zswap: dynamic po... |
1242 |
struct zswap_pool *pool; |
60105e124 mm/zswap: support... |
1243 |
|
90b0fc26d zswap: change zpo... |
1244 |
zswap_init_started = true; |
2b2811178 zswap: add to mm/ |
1245 1246 1247 |
if (zswap_entry_cache_create()) { pr_err("entry cache creation failed "); |
f1c54846e zswap: dynamic po... |
1248 |
goto cache_fail; |
2b2811178 zswap: add to mm/ |
1249 |
} |
f1c54846e zswap: dynamic po... |
1250 1251 1252 1253 1254 |
if (zswap_cpu_dstmem_init()) { pr_err("dstmem alloc failed "); goto dstmem_fail; |
2b2811178 zswap: add to mm/ |
1255 |
} |
f1c54846e zswap: dynamic po... |
1256 1257 1258 1259 1260 1261 |
pool = __zswap_pool_create_fallback(); if (!pool) { pr_err("pool creation failed "); goto pool_fail; |
2b2811178 zswap: add to mm/ |
1262 |
} |
f1c54846e zswap: dynamic po... |
1263 1264 1265 1266 1267 |
pr_info("loaded using pool %s/%s ", pool->tfm_name, zpool_get_type(pool->zpool)); list_add(&pool->list, &zswap_pools); |
60105e124 mm/zswap: support... |
1268 |
|
2b2811178 zswap: add to mm/ |
1269 1270 1271 1272 1273 |
frontswap_register_ops(&zswap_frontswap_ops); if (zswap_debugfs_init()) pr_warn("debugfs initialization failed "); return 0; |
f1c54846e zswap: dynamic po... |
1274 1275 1276 1277 |
pool_fail: zswap_cpu_dstmem_destroy(); dstmem_fail: |
c119239b1 mm/zswap.c: add _... |
1278 |
zswap_entry_cache_destroy(); |
f1c54846e zswap: dynamic po... |
1279 |
cache_fail: |
f0c3a0ac3 zswap: disable ch... |
1280 1281 1282 |
/* if built-in, we aren't unloaded on failure; don't allow use */ zswap_init_failed = true; zswap_enabled = false; |
2b2811178 zswap: add to mm/ |
1283 1284 1285 1286 1287 1288 |
return -ENOMEM; } /* must be late so crypto has time to come up */ late_initcall(init_zswap); MODULE_LICENSE("GPL"); |
68386da82 zbud, zswap: chan... |
1289 |
MODULE_AUTHOR("Seth Jennings <sjennings@variantweb.net>"); |
2b2811178 zswap: add to mm/ |
1290 |
MODULE_DESCRIPTION("Compressed cache for swap pages"); |