From 5036c3902054358ee293b8cecfea13342d8019e8 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 21 Dec 2015 10:51:02 +1100 Subject: raid5: allow r5l_io_unit allocations to fail And propagate the error up the stack so we can add the stripe to no_stripes_list and retry our log operation later. This avoids blocking raid5d due to reclaim, an it allows to get rid of the deadlock-prone GFP_NOFAIL allocation. shli: add missing mempool_destroy() Signed-off-by: Christoph Hellwig Signed-off-by: NeilBrown --- drivers/md/raid5-cache.c | 67 ++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 57 insertions(+), 10 deletions(-) (limited to 'drivers/md/raid5-cache.c') diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c index fa2d632..6d2b478 100644 --- a/drivers/md/raid5-cache.c +++ b/drivers/md/raid5-cache.c @@ -75,7 +75,10 @@ struct r5l_log { struct list_head finished_ios; /* io_units which settle down in log disk */ struct bio flush_bio; + struct list_head no_mem_stripes; /* pending stripes, -ENOMEM */ + struct kmem_cache *io_kc; + mempool_t *io_pool; struct bio_set *bs; mempool_t *meta_pool; @@ -287,8 +290,11 @@ static struct r5l_io_unit *r5l_new_meta(struct r5l_log *log) struct r5l_io_unit *io; struct r5l_meta_block *block; - /* We can't handle memory allocate failure so far */ - io = kmem_cache_zalloc(log->io_kc, GFP_NOIO | __GFP_NOFAIL); + io = mempool_alloc(log->io_pool, GFP_ATOMIC); + if (!io) + return NULL; + memset(io, 0, sizeof(*io)); + io->log = log; INIT_LIST_HEAD(&io->log_sibling); INIT_LIST_HEAD(&io->stripe_list); @@ -326,8 +332,12 @@ static int r5l_get_meta(struct r5l_log *log, unsigned int payload_size) log->current_io->meta_offset + payload_size > PAGE_SIZE) r5l_submit_current_io(log); - if (!log->current_io) + if (!log->current_io) { log->current_io = r5l_new_meta(log); + if (!log->current_io) + return -ENOMEM; + } + return 0; } @@ -372,11 +382,12 @@ static void r5l_append_payload_page(struct r5l_log *log, struct page *page) r5_reserve_log_entry(log, io); } -static void r5l_log_stripe(struct r5l_log *log, struct stripe_head *sh, +static int r5l_log_stripe(struct r5l_log *log, struct stripe_head *sh, int data_pages, int parity_pages) { int i; int meta_size; + int ret; struct r5l_io_unit *io; meta_size = @@ -385,7 +396,10 @@ static void r5l_log_stripe(struct r5l_log *log, struct stripe_head *sh, sizeof(struct r5l_payload_data_parity) + sizeof(__le32) * parity_pages; - r5l_get_meta(log, meta_size); + ret = r5l_get_meta(log, meta_size); + if (ret) + return ret; + io = log->current_io; for (i = 0; i < sh->disks; i++) { @@ -415,6 +429,8 @@ static void r5l_log_stripe(struct r5l_log *log, struct stripe_head *sh, list_add_tail(&sh->log_list, &io->stripe_list); atomic_inc(&io->pending_stripe); sh->log_io = io; + + return 0; } static void r5l_wake_reclaim(struct r5l_log *log, sector_t space); @@ -429,6 +445,7 @@ int r5l_write_stripe(struct r5l_log *log, struct stripe_head *sh) int meta_size; int reserve; int i; + int ret = 0; if (!log) return -EAGAIN; @@ -477,17 +494,22 @@ int r5l_write_stripe(struct r5l_log *log, struct stripe_head *sh) mutex_lock(&log->io_mutex); /* meta + data */ reserve = (1 + write_disks) << (PAGE_SHIFT - 9); - if (r5l_has_free_space(log, reserve)) - r5l_log_stripe(log, sh, data_pages, parity_pages); - else { + if (!r5l_has_free_space(log, reserve)) { spin_lock(&log->no_space_stripes_lock); list_add_tail(&sh->log_list, &log->no_space_stripes); spin_unlock(&log->no_space_stripes_lock); r5l_wake_reclaim(log, reserve); + } else { + ret = r5l_log_stripe(log, sh, data_pages, parity_pages); + if (ret) { + spin_lock_irq(&log->io_list_lock); + list_add_tail(&sh->log_list, &log->no_mem_stripes); + spin_unlock_irq(&log->io_list_lock); + } } - mutex_unlock(&log->io_mutex); + mutex_unlock(&log->io_mutex); return 0; } @@ -540,6 +562,21 @@ static sector_t r5l_reclaimable_space(struct r5l_log *log) log->next_checkpoint); } +static void r5l_run_no_mem_stripe(struct r5l_log *log) +{ + struct stripe_head *sh; + + assert_spin_locked(&log->io_list_lock); + + if (!list_empty(&log->no_mem_stripes)) { + sh = list_first_entry(&log->no_mem_stripes, + struct stripe_head, log_list); + list_del_init(&sh->log_list); + set_bit(STRIPE_HANDLE, &sh->state); + raid5_release_stripe(sh); + } +} + static bool r5l_complete_finished_ios(struct r5l_log *log) { struct r5l_io_unit *io, *next; @@ -556,7 +593,8 @@ static bool r5l_complete_finished_ios(struct r5l_log *log) log->next_cp_seq = io->seq; list_del(&io->log_sibling); - kmem_cache_free(log->io_kc, io); + mempool_free(io, log->io_pool); + r5l_run_no_mem_stripe(log); found = true; } @@ -1170,6 +1208,10 @@ int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev) if (!log->io_kc) goto io_kc; + log->io_pool = mempool_create_slab_pool(R5L_POOL_SIZE, log->io_kc); + if (!log->io_pool) + goto io_pool; + log->bs = bioset_create(R5L_POOL_SIZE, 0); if (!log->bs) goto io_bs; @@ -1184,6 +1226,8 @@ int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev) goto reclaim_thread; init_waitqueue_head(&log->iounit_wait); + INIT_LIST_HEAD(&log->no_mem_stripes); + INIT_LIST_HEAD(&log->no_space_stripes); spin_lock_init(&log->no_space_stripes_lock); @@ -1200,6 +1244,8 @@ reclaim_thread: out_mempool: bioset_free(log->bs); io_bs: + mempool_destroy(log->io_pool); +io_pool: kmem_cache_destroy(log->io_kc); io_kc: kfree(log); @@ -1211,6 +1257,7 @@ void r5l_exit_log(struct r5l_log *log) md_unregister_thread(&log->reclaim_thread); mempool_destroy(log->meta_pool); bioset_free(log->bs); + mempool_destroy(log->io_pool); kmem_cache_destroy(log->io_kc); kfree(log); } -- cgit v1.1