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authorChristoph Hellwig <hch@lst.de>2015-12-21 02:51:02 +0300
committerNeilBrown <neilb@suse.com>2016-01-06 03:40:12 +0300
commit5036c3902054358ee293b8cecfea13342d8019e8 (patch)
tree7b8c543a157bbdb99fe0af617ba1679a92968286 /drivers/md
parente8deb6381051bf3ce9d817020e8ba972b405a070 (diff)
downloadlinux-5036c3902054358ee293b8cecfea13342d8019e8.tar.xz
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 <hch@lst.de> Signed-off-by: NeilBrown <neilb@suse.com>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/raid5-cache.c67
1 files changed, 57 insertions, 10 deletions
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index fa2d6321f3a4..6d2b4789a928 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);
}