On Fri, Dec 19 2014 at 2:53pm -0500, Mike Snitzer <snitzer@xxxxxxxxxx> wrote: > On Thu, Dec 18 2014 at 10:37am -0500, > Mike Snitzer <snitzer@xxxxxxxxxx> wrote: > > > On Wed, Dec 17 2014 at 7:40pm -0500, > > Timofey Titovets <nefelim4ag@xxxxxxxxx> wrote: > > > > > io_schedule_timeout(5*HZ); > > > Introduced for avoidance dm bug: > > > http://linux.derkeiler.com/Mailing-Lists/Kernel/2006-08/msg04869.html > > > According to description must be replaced with io_schedule() ... > > So I'll have to read the thread you linked to to understand if DM raid1 > > (or DM core) still suffers from the problem that this hack papered over. > > Heinz also pointed out that the primary issue that forced the use of > io_schedule_timeout() was that dm-log-userspace (used by dm-raid1) makes > use of a single shared mempool for multiple devices. Unfortunately, > dm-log-userspace still has this shared mempool (flush_entry_pool). So > we'll need to fix that up to be per-device before mm/mempool.c code can > be switched to use io_schedule(). > > I'll add this to my TODO. But it'll have to wait until after the new > year. I finally got around to this. Heinz and/or Jon, would you be willing to test this? No real rush (won't go upstream until next merge window, 3.21). One question I have is: should FLUSH_ENTRY_POOL_SIZE be reduced from 100 (previous default global min_nr) now that this reserve is per-dirty-log? From: Mike Snitzer <snitzer@xxxxxxxxxx> Date: Thu, 12 Feb 2015 15:20:35 -0500 Subject: [PATCH] dm log userspace: split flush_entry_pool to be per dirty-log Use a single slab cache to allocate a mempool for each dirty-log. This _should_ eliminate DM's need for io_schedule_timeout() in mempool_alloc(); so io_schedule() should be sufficient now. Also, rename struct flush_entry to dm_dirty_log_flush_entry to allow KMEM_CACHE() to create a meaningful global name for the slab cache. Also, eliminate some holes in struct log_c by rearranging members. Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> --- drivers/md/dm-log-userspace-base.c | 84 ++++++++++++++++++++------------------ 1 file changed, 45 insertions(+), 39 deletions(-) diff --git a/drivers/md/dm-log-userspace-base.c b/drivers/md/dm-log-userspace-base.c index 03177ca..266bffc 100644 --- a/drivers/md/dm-log-userspace-base.c +++ b/drivers/md/dm-log-userspace-base.c @@ -17,7 +17,9 @@ #define DM_LOG_USERSPACE_VSN "1.3.0" -struct flush_entry { +#define FLUSH_ENTRY_POOL_SIZE 100 + +struct dm_dirty_log_flush_entry { int type; region_t region; struct list_head list; @@ -34,22 +36,14 @@ struct flush_entry { struct log_c { struct dm_target *ti; struct dm_dev *log_dev; - uint32_t region_size; - region_t region_count; - uint64_t luid; - char uuid[DM_UUID_LEN]; char *usr_argv_str; uint32_t usr_argc; - /* - * in_sync_hint gets set when doing is_remote_recovering. It - * represents the first region that needs recovery. IOW, the - * first zero bit of sync_bits. This can be useful for to limit - * traffic for calls like is_remote_recovering and get_resync_work, - * but be take care in its use for anything else. - */ - uint64_t in_sync_hint; + uint32_t region_size; + region_t region_count; + uint64_t luid; + char uuid[DM_UUID_LEN]; /* * Mark and clear requests are held until a flush is issued @@ -62,6 +56,15 @@ struct log_c { struct list_head clear_list; /* + * in_sync_hint gets set when doing is_remote_recovering. It + * represents the first region that needs recovery. IOW, the + * first zero bit of sync_bits. This can be useful for to limit + * traffic for calls like is_remote_recovering and get_resync_work, + * but be take care in its use for anything else. + */ + uint64_t in_sync_hint; + + /* * Workqueue for flush of clear region requests. */ struct workqueue_struct *dmlog_wq; @@ -72,19 +75,11 @@ struct log_c { * Combine userspace flush and mark requests for efficiency. */ uint32_t integrated_flush; -}; - -static mempool_t *flush_entry_pool; -static void *flush_entry_alloc(gfp_t gfp_mask, void *pool_data) -{ - return kmalloc(sizeof(struct flush_entry), gfp_mask); -} + mempool_t *flush_entry_pool; +}; -static void flush_entry_free(void *element, void *pool_data) -{ - kfree(element); -} +static struct kmem_cache *_flush_entry_cache; static int userspace_do_request(struct log_c *lc, const char *uuid, int request_type, char *data, size_t data_size, @@ -254,6 +249,14 @@ static int userspace_ctr(struct dm_dirty_log *log, struct dm_target *ti, goto out; } + lc->flush_entry_pool = mempool_create_slab_pool(FLUSH_ENTRY_POOL_SIZE, + _flush_entry_cache); + if (!lc->flush_entry_pool) { + DMERR("Failed to create flush_entry_pool"); + r = -ENOMEM; + goto out; + } + /* * Send table string and get back any opened device. */ @@ -310,6 +313,8 @@ static int userspace_ctr(struct dm_dirty_log *log, struct dm_target *ti, out: kfree(devices_rdata); if (r) { + if (lc->flush_entry_pool) + mempool_destroy(lc->flush_entry_pool); kfree(lc); kfree(ctr_str); } else { @@ -338,6 +343,8 @@ static void userspace_dtr(struct dm_dirty_log *log) if (lc->log_dev) dm_put_device(lc->ti, lc->log_dev); + mempool_destroy(lc->flush_entry_pool); + kfree(lc->usr_argv_str); kfree(lc); @@ -461,7 +468,7 @@ static int userspace_in_sync(struct dm_dirty_log *log, region_t region, static int flush_one_by_one(struct log_c *lc, struct list_head *flush_list) { int r = 0; - struct flush_entry *fe; + struct dm_dirty_log_flush_entry *fe; list_for_each_entry(fe, flush_list, list) { r = userspace_do_request(lc, lc->uuid, fe->type, @@ -481,7 +488,7 @@ static int flush_by_group(struct log_c *lc, struct list_head *flush_list, int r = 0; int count; uint32_t type = 0; - struct flush_entry *fe, *tmp_fe; + struct dm_dirty_log_flush_entry *fe, *tmp_fe; LIST_HEAD(tmp_list); uint64_t group[MAX_FLUSH_GROUP_COUNT]; @@ -563,7 +570,8 @@ static int userspace_flush(struct dm_dirty_log *log) LIST_HEAD(clear_list); int mark_list_is_empty; int clear_list_is_empty; - struct flush_entry *fe, *tmp_fe; + struct dm_dirty_log_flush_entry *fe, *tmp_fe; + mempool_t *flush_entry_pool = lc->flush_entry_pool; spin_lock_irqsave(&lc->flush_lock, flags); list_splice_init(&lc->mark_list, &mark_list); @@ -643,10 +651,10 @@ static void userspace_mark_region(struct dm_dirty_log *log, region_t region) { unsigned long flags; struct log_c *lc = log->context; - struct flush_entry *fe; + struct dm_dirty_log_flush_entry *fe; /* Wait for an allocation, but _never_ fail */ - fe = mempool_alloc(flush_entry_pool, GFP_NOIO); + fe = mempool_alloc(lc->flush_entry_pool, GFP_NOIO); BUG_ON(!fe); spin_lock_irqsave(&lc->flush_lock, flags); @@ -672,7 +680,7 @@ static void userspace_clear_region(struct dm_dirty_log *log, region_t region) { unsigned long flags; struct log_c *lc = log->context; - struct flush_entry *fe; + struct dm_dirty_log_flush_entry *fe; /* * If we fail to allocate, we skip the clearing of @@ -680,7 +688,7 @@ static void userspace_clear_region(struct dm_dirty_log *log, region_t region) * to cause the region to be resync'ed when the * device is activated next time. */ - fe = mempool_alloc(flush_entry_pool, GFP_ATOMIC); + fe = mempool_alloc(lc->flush_entry_pool, GFP_ATOMIC); if (!fe) { DMERR("Failed to allocate memory to clear region."); return; @@ -886,18 +894,16 @@ static int __init userspace_dirty_log_init(void) { int r = 0; - flush_entry_pool = mempool_create(100, flush_entry_alloc, - flush_entry_free, NULL); - - if (!flush_entry_pool) { - DMWARN("Unable to create flush_entry_pool: No memory."); + _flush_entry_cache = KMEM_CACHE(dm_dirty_log_flush_entry, 0); + if (!_flush_entry_cache) { + DMWARN("Unable to create flush_entry_cache: No memory."); return -ENOMEM; } r = dm_ulog_tfr_init(); if (r) { DMWARN("Unable to initialize userspace log communications"); - mempool_destroy(flush_entry_pool); + kmem_cache_destroy(_flush_entry_cache); return r; } @@ -905,7 +911,7 @@ static int __init userspace_dirty_log_init(void) if (r) { DMWARN("Couldn't register userspace dirty log type"); dm_ulog_tfr_exit(); - mempool_destroy(flush_entry_pool); + kmem_cache_destroy(_flush_entry_cache); return r; } @@ -917,7 +923,7 @@ static void __exit userspace_dirty_log_exit(void) { dm_dirty_log_type_unregister(&_userspace_type); dm_ulog_tfr_exit(); - mempool_destroy(flush_entry_pool); + kmem_cache_destroy(_flush_entry_cache); DMINFO("version " DM_LOG_USERSPACE_VSN " unloaded"); return; -- 1.8.3.1 -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
