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Message-ID: <20150618155730.GA9958@cerebellum.local.variantweb.net>
Date: Thu, 18 Jun 2015 10:57:30 -0500
From: Seth Jennings <sjennings@...iantweb.net>
To: Dan Streetman <ddstreet@...e.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
Linux-MM <linux-mm@...ck.org>,
linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] zswap: dynamic pool creation
On Thu, Jun 11, 2015 at 01:51:45PM -0500, Seth Jennings wrote:
> On Wed, Jun 10, 2015 at 04:54:24PM -0400, Dan Streetman wrote:
> > On Thu, Jun 4, 2015 at 8:13 AM, Dan Streetman <ddstreet@...e.org> wrote:
> > > On Thu, Jun 4, 2015 at 8:02 AM, Dan Streetman <ddstreet@...e.org> wrote:
> > >> Add dynamic creation of pools. Move the static crypto compression
> > >> per-cpu transforms into each pool. Add a pointer to zswap_entry to
> > >> the pool it's in.
> > >
> > > Seth, as far as the design, from your previous comments I assume you
> > > were thinking of maintaining separate lists of zpools and compressors?
> > > I do see how that will reduce duplication of zpools and compressors,
> > > but it also requires adding a new pointer to each zswap_entry, and
> > > increasing the amount of code to manage each list separately. And the
> > > most common case in zswap will be just a single zpool and compressor,
> > > not repeatedly changing params. What do you think?
> >
> > Any opinion on this patch? If you want, I can break it up so there's
> > a list of zpools and a list of compressors. Either the combined way
> > (this patch) or separate lists works for me, as long as the params are
> > changeable at runtime :-)
>
> I'm still reviewing the code. I was going to test it too but it doesn't
> compile for me:
>
> CC mm/zswap.o
> mm/zswap.c: In function ‘__zswap_pool_create_fallback’:
> mm/zswap.c:605:10: warning: argument to ‘sizeof’ in ‘strncpy’ call is the same expression as the destination; did you mean to provide an explicit length? [-Wsizeof-pointer-memaccess]
> sizeof(zswap_compressor));
> ^
> mm/zswap.c:607:7: error: implicit declaration of function ‘zpool_has_pool’ [-Werror=implicit-function-declaration]
> if (!zpool_has_pool(zswap_zpool_type)) {
> ^
> mm/zswap.c:611:10: warning: argument to ‘sizeof’ in ‘strncpy’ call is the same expression as the destination; did you mean to provide an explicit length? [-Wsizeof-pointer-memaccess]
> sizeof(zswap_zpool_type));
> ^
> mm/zswap.c: At top level:
> mm/zswap.c:664:1: error: expected identifier or ‘(’ before ‘}’ token
> }
> ^
> mm/zswap.c:99:22: warning: ‘zswap_pool’ defined but not used [-Wunused-variable]
> static struct zpool *zswap_pool;
> ^
> mm/zswap.c:531:27: warning: ‘zswap_pool_find_get’ defined but not used [-Wunused-function]
> static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
> ^
Dan, I never heard back from you on this, but I figured it out. PATCH
1/5 from your original patchset wasn't pulled in, but you didn't roll it
into this new patch either.
Seth
>
> Seth
>
> >
> >
> > >
> > >>
> > >> This is required by a separate patch which enables changing the
> > >> zswap zpool and compressor params at runtime.
> > >>
> > >> Signed-off-by: Dan Streetman <ddstreet@...e.org>
> > >> ---
> > >> mm/zswap.c | 550 +++++++++++++++++++++++++++++++++++++++++++++----------------
> > >> 1 file changed, 408 insertions(+), 142 deletions(-)
> > >>
> > >> diff --git a/mm/zswap.c b/mm/zswap.c
> > >> index 2d5727b..fc93770 100644
> > >> --- a/mm/zswap.c
> > >> +++ b/mm/zswap.c
> > >> @@ -99,66 +99,19 @@ module_param_named(zpool, zswap_zpool_type, charp, 0444);
> > >> static struct zpool *zswap_pool;
> > >>
> > >> /*********************************
> > >> -* compression functions
> > >> +* data structures
> > >> **********************************/
> > >> -/* per-cpu compression transforms */
> > >> -static struct crypto_comp * __percpu *zswap_comp_pcpu_tfms;
> > >>
> > >> -enum comp_op {
> > >> - ZSWAP_COMPOP_COMPRESS,
> > >> - ZSWAP_COMPOP_DECOMPRESS
> > >> +struct zswap_pool {
> > >> + struct zpool *zpool;
> > >> + struct kref kref;
> > >> + struct list_head list;
> > >> + struct rcu_head rcu_head;
> > >> + struct notifier_block notifier;
> > >> + char tfm_name[CRYPTO_MAX_ALG_NAME];
> > >> + struct crypto_comp * __percpu *tfm;
> > >> };
> > >>
> > >> -static int zswap_comp_op(enum comp_op op, const u8 *src, unsigned int slen,
> > >> - u8 *dst, unsigned int *dlen)
> > >> -{
> > >> - struct crypto_comp *tfm;
> > >> - int ret;
> > >> -
> > >> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, get_cpu());
> > >> - switch (op) {
> > >> - case ZSWAP_COMPOP_COMPRESS:
> > >> - ret = crypto_comp_compress(tfm, src, slen, dst, dlen);
> > >> - break;
> > >> - case ZSWAP_COMPOP_DECOMPRESS:
> > >> - ret = crypto_comp_decompress(tfm, src, slen, dst, dlen);
> > >> - break;
> > >> - default:
> > >> - ret = -EINVAL;
> > >> - }
> > >> -
> > >> - put_cpu();
> > >> - return ret;
> > >> -}
> > >> -
> > >> -static int __init zswap_comp_init(void)
> > >> -{
> > >> - if (!crypto_has_comp(zswap_compressor, 0, 0)) {
> > >> - pr_info("%s compressor not available\n", zswap_compressor);
> > >> - /* fall back to default compressor */
> > >> - zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;
> > >> - if (!crypto_has_comp(zswap_compressor, 0, 0))
> > >> - /* can't even load the default compressor */
> > >> - return -ENODEV;
> > >> - }
> > >> - pr_info("using %s compressor\n", zswap_compressor);
> > >> -
> > >> - /* alloc percpu transforms */
> > >> - zswap_comp_pcpu_tfms = alloc_percpu(struct crypto_comp *);
> > >> - if (!zswap_comp_pcpu_tfms)
> > >> - return -ENOMEM;
> > >> - return 0;
> > >> -}
> > >> -
> > >> -static void __init zswap_comp_exit(void)
> > >> -{
> > >> - /* free percpu transforms */
> > >> - free_percpu(zswap_comp_pcpu_tfms);
> > >> -}
> > >> -
> > >> -/*********************************
> > >> -* data structures
> > >> -**********************************/
> > >> /*
> > >> * struct zswap_entry
> > >> *
> > >> @@ -166,22 +119,24 @@ static void __init zswap_comp_exit(void)
> > >> * page within zswap.
> > >> *
> > >> * rbnode - links the entry into red-black tree for the appropriate swap type
> > >> + * offset - the swap offset for the entry. Index into the red-black tree.
> > >> * refcount - the number of outstanding reference to the entry. This is needed
> > >> * to protect against premature freeing of the entry by code
> > >> * concurrent calls to load, invalidate, and writeback. The lock
> > >> * 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.
> > >> - * offset - the swap offset for the entry. Index into the red-black tree.
> > >> - * handle - zpool allocation handle that stores the compressed page data
> > >> * length - the length in bytes of the compressed page data. Needed during
> > >> * decompression
> > >> + * pool - the zswap_pool the entry's data is in
> > >> + * handle - zpool allocation handle that stores the compressed page data
> > >> */
> > >> struct zswap_entry {
> > >> struct rb_node rbnode;
> > >> pgoff_t offset;
> > >> int refcount;
> > >> unsigned int length;
> > >> + struct zswap_pool *pool;
> > >> unsigned long handle;
> > >> };
> > >>
> > >> @@ -201,6 +156,44 @@ struct zswap_tree {
> > >>
> > >> static struct zswap_tree *zswap_trees[MAX_SWAPFILES];
> > >>
> > >> +/* RCU-protected iteration */
> > >> +static LIST_HEAD(zswap_pools);
> > >> +/* protects zswap_pools list modification */
> > >> +static DEFINE_SPINLOCK(zswap_pools_lock);
> > >> +
> > >> +/*********************************
> > >> +* helpers and fwd declarations
> > >> +**********************************/
> > >> +
> > >> +#define zswap_pool_debug(msg, p) \
> > >> + pr_debug("%s pool %s/%s\n", 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 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;
> > >> +}
> > >> +
> > >> /*********************************
> > >> * zswap entry functions
> > >> **********************************/
> > >> @@ -294,10 +287,11 @@ static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry)
> > >> */
> > >> static void zswap_free_entry(struct zswap_entry *entry)
> > >> {
> > >> - zpool_free(zswap_pool, entry->handle);
> > >> + zpool_free(entry->pool->zpool, entry->handle);
> > >> + zswap_pool_put(entry->pool);
> > >> zswap_entry_cache_free(entry);
> > >> atomic_dec(&zswap_stored_pages);
> > >> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
> > >> + zswap_update_total_size();
> > >> }
> > >>
> > >> /* caller must hold the tree lock */
> > >> @@ -339,35 +333,21 @@ static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
> > >> **********************************/
> > >> static DEFINE_PER_CPU(u8 *, zswap_dstmem);
> > >>
> > >> -static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
> > >> +static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
> > >> {
> > >> - struct crypto_comp *tfm;
> > >> u8 *dst;
> > >>
> > >> switch (action) {
> > >> case CPU_UP_PREPARE:
> > >> - tfm = crypto_alloc_comp(zswap_compressor, 0, 0);
> > >> - if (IS_ERR(tfm)) {
> > >> - pr_err("can't allocate compressor transform\n");
> > >> - return NOTIFY_BAD;
> > >> - }
> > >> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = tfm;
> > >> dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
> > >> if (!dst) {
> > >> pr_err("can't allocate compressor buffer\n");
> > >> - crypto_free_comp(tfm);
> > >> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
> > >> return NOTIFY_BAD;
> > >> }
> > >> per_cpu(zswap_dstmem, cpu) = dst;
> > >> break;
> > >> case CPU_DEAD:
> > >> case CPU_UP_CANCELED:
> > >> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu);
> > >> - if (tfm) {
> > >> - crypto_free_comp(tfm);
> > >> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
> > >> - }
> > >> dst = per_cpu(zswap_dstmem, cpu);
> > >> kfree(dst);
> > >> per_cpu(zswap_dstmem, cpu) = NULL;
> > >> @@ -378,43 +358,309 @@ static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
> > >> return NOTIFY_OK;
> > >> }
> > >>
> > >> -static int zswap_cpu_notifier(struct notifier_block *nb,
> > >> - unsigned long action, void *pcpu)
> > >> +static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
> > >> + unsigned long action, void *pcpu)
> > >> {
> > >> - unsigned long cpu = (unsigned long)pcpu;
> > >> - return __zswap_cpu_notifier(action, cpu);
> > >> + return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
> > >> }
> > >>
> > >> -static struct notifier_block zswap_cpu_notifier_block = {
> > >> - .notifier_call = zswap_cpu_notifier
> > >> +static struct notifier_block zswap_dstmem_notifier = {
> > >> + .notifier_call = zswap_cpu_dstmem_notifier,
> > >> };
> > >>
> > >> -static int __init zswap_cpu_init(void)
> > >> +static int __init zswap_cpu_dstmem_init(void)
> > >> {
> > >> unsigned long cpu;
> > >>
> > >> cpu_notifier_register_begin();
> > >> for_each_online_cpu(cpu)
> > >> - if (__zswap_cpu_notifier(CPU_UP_PREPARE, cpu) != NOTIFY_OK)
> > >> + if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
> > >> + NOTIFY_BAD)
> > >> goto cleanup;
> > >> - __register_cpu_notifier(&zswap_cpu_notifier_block);
> > >> + __register_cpu_notifier(&zswap_dstmem_notifier);
> > >> cpu_notifier_register_done();
> > >> return 0;
> > >>
> > >> cleanup:
> > >> for_each_online_cpu(cpu)
> > >> - __zswap_cpu_notifier(CPU_UP_CANCELED, 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\n",
> > >> + 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)
> > >> +{
> > >> + unsigned long cpu;
> > >> +
> > >> + memset(&pool->notifier, 0, sizeof(pool->notifier));
> > >> + pool->notifier.notifier_call = zswap_cpu_comp_notifier;
> > >> +
> > >> + cpu_notifier_register_begin();
> > >> + for_each_online_cpu(cpu)
> > >> + if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) ==
> > >> + NOTIFY_BAD)
> > >> + goto cleanup;
> > >> + __register_cpu_notifier(&pool->notifier);
> > >> + cpu_notifier_register_done();
> > >> + return 0;
> > >> +
> > >> +cleanup:
> > >> + for_each_online_cpu(cpu)
> > >> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
> > >> + cpu_notifier_register_done();
> > >> + return -ENOMEM;
> > >> +}
> > >> +
> > >> +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();
> > >> +}
> > >> +
> > >> /*********************************
> > >> -* helpers
> > >> +* pool functions
> > >> **********************************/
> > >> -static bool zswap_is_full(void)
> > >> +
> > >> +static struct zswap_pool *__zswap_pool_current(void)
> > >> {
> > >> - return totalram_pages * zswap_max_pool_percent / 100 <
> > >> - DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
> > >> + 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;
> > >> +}
> > >> +
> > >> +static struct zpool_ops zswap_zpool_ops = {
> > >> + .evict = zswap_writeback_entry
> > >> +};
> > >> +
> > >> +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) {
> > >> + if (strncmp(pool->tfm_name, compressor, sizeof(pool->tfm_name)))
> > >> + continue;
> > >> + if (strncmp(zpool_get_type(pool->zpool), type,
> > >> + sizeof(zswap_zpool_type)))
> > >> + 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;
> > >> + gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
> > >> +
> > >> + pool = kzalloc(sizeof(*pool), GFP_KERNEL);
> > >> + if (!pool) {
> > >> + pr_err("pool alloc failed\n");
> > >> + return NULL;
> > >> + }
> > >> +
> > >> + pool->zpool = zpool_create_pool(type, "zswap", gfp, &zswap_zpool_ops);
> > >> + if (!pool->zpool) {
> > >> + pr_err("%s zpool not available\n", type);
> > >> + goto error;
> > >> + }
> > >> + pr_debug("using %s zpool\n", 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\n");
> > >> + goto error;
> > >> + }
> > >> +
> > >> + if (zswap_cpu_comp_init(pool))
> > >> + goto error;
> > >> + pr_debug("using %s compressor\n", 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;
> > >> +}
> > >> +
> > >> +static struct zswap_pool *__zswap_pool_create_fallback(void)
> > >> +{
> > >> + if (!crypto_has_comp(zswap_compressor, 0, 0)) {
> > >> + pr_err("compressor %s not available, using default %s\n",
> > >> + zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT);
> > >> + strncpy(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT,
> > >> + sizeof(zswap_compressor));
> > >> + }
> > >> + if (!zpool_has_pool(zswap_zpool_type)) {
> > >> + pr_err("zpool %s not available, using default %s\n",
> > >> + zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT);
> > >> + strncpy(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT,
> > >> + sizeof(zswap_zpool_type));
> > >> + }
> > >> +
> > >> + 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);
> > >> +}
> > >> +
> > >> +static void __zswap_pool_release(struct rcu_head *head)
> > >> +{
> > >> + struct zswap_pool *pool = container_of(head, typeof(*pool), rcu_head);
> > >> +
> > >> + /* 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);
> > >> + call_rcu(&pool->rcu_head, __zswap_pool_release);
> > >> +
> > >> + spin_unlock(&zswap_pools_lock);
> > >> +}
> > >> +
> > >> +static void zswap_pool_put(struct zswap_pool *pool)
> > >> +{
> > >> + kref_put(&pool->kref, __zswap_pool_empty);
> > >> +}
> > >> +
> > >> }
> > >>
> > >> /*********************************
> > >> @@ -538,6 +784,7 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
> > >> pgoff_t offset;
> > >> struct zswap_entry *entry;
> > >> struct page *page;
> > >> + struct crypto_comp *tfm;
> > >> u8 *src, *dst;
> > >> unsigned int dlen;
> > >> int ret;
> > >> @@ -578,13 +825,15 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
> > >> case ZSWAP_SWAPCACHE_NEW: /* page is locked */
> > >> /* decompress */
> > >> dlen = PAGE_SIZE;
> > >> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
> > >> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
> > >> ZPOOL_MM_RO) + sizeof(struct zswap_header);
> > >> dst = kmap_atomic(page);
> > >> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src,
> > >> - entry->length, dst, &dlen);
> > >> + tfm = *get_cpu_ptr(entry->pool->tfm);
> > >> + ret = crypto_comp_decompress(tfm, src, entry->length,
> > >> + dst, &dlen);
> > >> + put_cpu_ptr(entry->pool->tfm);
> > >> kunmap_atomic(dst);
> > >> - zpool_unmap_handle(zswap_pool, entry->handle);
> > >> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
> > >> BUG_ON(ret);
> > >> BUG_ON(dlen != PAGE_SIZE);
> > >>
> > >> @@ -633,6 +882,22 @@ end:
> > >> return ret;
> > >> }
> > >>
> > >> +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;
> > >> +}
> > >> +
> > >> /*********************************
> > >> * frontswap hooks
> > >> **********************************/
> > >> @@ -642,6 +907,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> > >> {
> > >> struct zswap_tree *tree = zswap_trees[type];
> > >> struct zswap_entry *entry, *dupentry;
> > >> + struct crypto_comp *tfm;
> > >> int ret;
> > >> unsigned int dlen = PAGE_SIZE, len;
> > >> unsigned long handle;
> > >> @@ -657,7 +923,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> > >> /* reclaim space if needed */
> > >> if (zswap_is_full()) {
> > >> zswap_pool_limit_hit++;
> > >> - if (zpool_shrink(zswap_pool, 1, NULL)) {
> > >> + if (zswap_shrink()) {
> > >> zswap_reject_reclaim_fail++;
> > >> ret = -ENOMEM;
> > >> goto reject;
> > >> @@ -672,33 +938,42 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> > >> goto reject;
> > >> }
> > >>
> > >> + /* if entry is successfully added, it keeps the reference */
> > >> + entry->pool = zswap_pool_current_get();
> > >> + if (!entry->pool) {
> > >> + ret = -EINVAL;
> > >> + goto freepage;
> > >> + }
> > >> +
> > >> /* compress */
> > >> dst = get_cpu_var(zswap_dstmem);
> > >> + tfm = *get_cpu_ptr(entry->pool->tfm);
> > >> src = kmap_atomic(page);
> > >> - ret = zswap_comp_op(ZSWAP_COMPOP_COMPRESS, src, PAGE_SIZE, dst, &dlen);
> > >> + ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
> > >> kunmap_atomic(src);
> > >> + put_cpu_ptr(entry->pool->tfm);
> > >> if (ret) {
> > >> ret = -EINVAL;
> > >> - goto freepage;
> > >> + goto put_dstmem;
> > >> }
> > >>
> > >> /* store */
> > >> len = dlen + sizeof(struct zswap_header);
> > >> - ret = zpool_malloc(zswap_pool, len, __GFP_NORETRY | __GFP_NOWARN,
> > >> - &handle);
> > >> + ret = zpool_malloc(entry->pool->zpool, len,
> > >> + __GFP_NORETRY | __GFP_NOWARN, &handle);
> > >> if (ret == -ENOSPC) {
> > >> zswap_reject_compress_poor++;
> > >> - goto freepage;
> > >> + goto put_dstmem;
> > >> }
> > >> if (ret) {
> > >> zswap_reject_alloc_fail++;
> > >> - goto freepage;
> > >> + goto put_dstmem;
> > >> }
> > >> - zhdr = zpool_map_handle(zswap_pool, handle, ZPOOL_MM_RW);
> > >> + zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW);
> > >> zhdr->swpentry = swp_entry(type, offset);
> > >> buf = (u8 *)(zhdr + 1);
> > >> memcpy(buf, dst, dlen);
> > >> - zpool_unmap_handle(zswap_pool, handle);
> > >> + zpool_unmap_handle(entry->pool->zpool, handle);
> > >> put_cpu_var(zswap_dstmem);
> > >>
> > >> /* populate entry */
> > >> @@ -721,12 +996,14 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> > >>
> > >> /* update stats */
> > >> atomic_inc(&zswap_stored_pages);
> > >> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
> > >> + zswap_update_total_size();
> > >>
> > >> return 0;
> > >>
> > >> -freepage:
> > >> +put_dstmem:
> > >> put_cpu_var(zswap_dstmem);
> > >> + zswap_pool_put(entry->pool);
> > >> +freepage:
> > >> zswap_entry_cache_free(entry);
> > >> reject:
> > >> return ret;
> > >> @@ -741,6 +1018,7 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
> > >> {
> > >> struct zswap_tree *tree = zswap_trees[type];
> > >> struct zswap_entry *entry;
> > >> + struct crypto_comp *tfm;
> > >> u8 *src, *dst;
> > >> unsigned int dlen;
> > >> int ret;
> > >> @@ -757,13 +1035,14 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
> > >>
> > >> /* decompress */
> > >> dlen = PAGE_SIZE;
> > >> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
> > >> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
> > >> ZPOOL_MM_RO) + sizeof(struct zswap_header);
> > >> dst = kmap_atomic(page);
> > >> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src, entry->length,
> > >> - dst, &dlen);
> > >> + tfm = *get_cpu_ptr(entry->pool->tfm);
> > >> + ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen);
> > >> + put_cpu_ptr(entry->pool->tfm);
> > >> kunmap_atomic(dst);
> > >> - zpool_unmap_handle(zswap_pool, entry->handle);
> > >> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
> > >> BUG_ON(ret);
> > >>
> > >> spin_lock(&tree->lock);
> > >> @@ -816,10 +1095,6 @@ static void zswap_frontswap_invalidate_area(unsigned type)
> > >> zswap_trees[type] = NULL;
> > >> }
> > >>
> > >> -static struct zpool_ops zswap_zpool_ops = {
> > >> - .evict = zswap_writeback_entry
> > >> -};
> > >> -
> > >> static void zswap_frontswap_init(unsigned type)
> > >> {
> > >> struct zswap_tree *tree;
> > >> @@ -900,49 +1175,40 @@ static void __exit zswap_debugfs_exit(void) { }
> > >> **********************************/
> > >> static int __init init_zswap(void)
> > >> {
> > >> - gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
> > >> + struct zswap_pool *pool;
> > >>
> > >> - pr_info("loading zswap\n");
> > >> -
> > >> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
> > >> - &zswap_zpool_ops);
> > >> - if (!zswap_pool && strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) {
> > >> - pr_info("%s zpool not available\n", zswap_zpool_type);
> > >> - zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
> > >> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
> > >> - &zswap_zpool_ops);
> > >> - }
> > >> - if (!zswap_pool) {
> > >> - pr_err("%s zpool not available\n", zswap_zpool_type);
> > >> - pr_err("zpool creation failed\n");
> > >> - goto error;
> > >> - }
> > >> - pr_info("using %s pool\n", zswap_zpool_type);
> > >> + pr_info("loading\n");
> > >>
> > >> if (zswap_entry_cache_create()) {
> > >> pr_err("entry cache creation failed\n");
> > >> - goto cachefail;
> > >> + goto cache_fail;
> > >> }
> > >> - if (zswap_comp_init()) {
> > >> - pr_err("compressor initialization failed\n");
> > >> - goto compfail;
> > >> +
> > >> + if (zswap_cpu_dstmem_init()) {
> > >> + pr_err("dstmem alloc failed\n");
> > >> + goto dstmem_fail;
> > >> }
> > >> - if (zswap_cpu_init()) {
> > >> - pr_err("per-cpu initialization failed\n");
> > >> - goto pcpufail;
> > >> +
> > >> + pool = __zswap_pool_create_fallback();
> > >> + if (!pool) {
> > >> + pr_err("pool creation failed\n");
> > >> + goto pool_fail;
> > >> }
> > >> + pr_info("loaded using pool %s/%s\n", pool->tfm_name,
> > >> + zpool_get_type(pool->zpool));
> > >> +
> > >> + list_add(&pool->list, &zswap_pools);
> > >>
> > >> frontswap_register_ops(&zswap_frontswap_ops);
> > >> if (zswap_debugfs_init())
> > >> pr_warn("debugfs initialization failed\n");
> > >> return 0;
> > >> -pcpufail:
> > >> - zswap_comp_exit();
> > >> -compfail:
> > >> +
> > >> +pool_fail:
> > >> + zswap_cpu_dstmem_destroy();
> > >> +dstmem_fail:
> > >> zswap_entry_cache_destroy();
> > >> -cachefail:
> > >> - zpool_destroy_pool(zswap_pool);
> > >> -error:
> > >> +cache_fail:
> > >> return -ENOMEM;
> > >> }
> > >> /* must be late so crypto has time to come up */
> > >> --
> > >> 2.1.0
> > >>
--
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