Hi
This is update "retain write ordering" patch that hopefully fixes the
lockup.
Please test it in the situation where you saw performance degradation due
to dm-crypt parallelization patches.
From: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Reorder outgoing write requests so they submitted in the same order they
were received in.
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
---
drivers/md/dm-crypt.c | 55 ++++++++++++++++++++++++++++++++++++++++----------
1 file changed, 45 insertions(+), 10 deletions(-)
Index: linux-3.16/drivers/md/dm-crypt.c
===================================================================
--- linux-3.16.orig/drivers/md/dm-crypt.c 2014-09-17 19:54:33.000000000 +0200
+++ linux-3.16/drivers/md/dm-crypt.c 2014-09-17 19:54:35.000000000 +0200
@@ -61,6 +61,8 @@ struct dm_crypt_io {
sector_t sector;
struct list_head list;
+
+ unsigned long sequence;
} CRYPTO_MINALIGN_ATTR;
struct dm_crypt_request {
@@ -135,6 +137,9 @@ struct crypt_config {
wait_queue_head_t write_thread_wait;
struct list_head write_thread_list;
+ unsigned long write_sequence;
+ atomic_long_t alloc_sequence;
+
char *cipher;
char *cipher_string;
@@ -1177,7 +1182,9 @@ static int dmcrypt_write(void *data)
{
struct crypt_config *cc = data;
while (1) {
+ struct dm_crypt_io *io;
struct list_head local_list;
+ unsigned spinlock_breaker;
struct blk_plug plug;
DECLARE_WAITQUEUE(wait, current);
@@ -1185,8 +1192,31 @@ static int dmcrypt_write(void *data)
spin_lock_irq(&cc->write_thread_wait.lock);
continue_locked:
- if (!list_empty(&cc->write_thread_list))
- goto pop_from_list;
+ INIT_LIST_HEAD(&local_list);
+ spinlock_breaker = 0;
+
+ while (!list_empty(&cc->write_thread_list)) {
+ io = container_of(cc->write_thread_list.next,
+ struct dm_crypt_io, list);
+
+ BUG_ON((long)(io->sequence - cc->write_sequence) < 0);
+ if (io->sequence != cc->write_sequence)
+ break;
+
+ cc->write_sequence++;
+
+ list_del(&io->list);
+ list_add_tail(&io->list, &local_list);
+ if (unlikely(!(++spinlock_breaker & 63))) {
+ spin_unlock_irq(&cc->write_thread_wait.lock);
+ spin_lock_irq(&cc->write_thread_wait.lock);
+ }
+ }
+
+ if (!list_empty(&local_list)) {
+ spin_unlock_irq(&cc->write_thread_wait.lock);
+ goto flush_local_list;
+ }
__set_current_state(TASK_INTERRUPTIBLE);
__add_wait_queue(&cc->write_thread_wait, &wait);
@@ -1206,14 +1236,8 @@ continue_locked:
__remove_wait_queue(&cc->write_thread_wait, &wait);
goto continue_locked;
-pop_from_list:
- local_list = cc->write_thread_list;
- local_list.next->prev = &local_list;
- local_list.prev->next = &local_list;
- INIT_LIST_HEAD(&cc->write_thread_list);
-
- spin_unlock_irq(&cc->write_thread_wait.lock);
+flush_local_list:
blk_start_plug(&plug);
do {
struct dm_crypt_io *io = container_of(local_list.next,
@@ -1231,6 +1255,7 @@ static void kcryptd_crypt_write_io_submi
struct bio *clone = io->ctx.bio_out;
struct crypt_config *cc = io->cc;
unsigned long flags;
+ struct dm_crypt_io *io_list;
if (unlikely(io->error < 0)) {
crypt_free_buffer_pages(cc, clone);
@@ -1245,8 +1270,15 @@ static void kcryptd_crypt_write_io_submi
clone->bi_iter.bi_sector = cc->start + io->sector;
spin_lock_irqsave(&cc->write_thread_wait.lock, flags);
- list_add_tail(&io->list, &cc->write_thread_list);
+ list_for_each_entry_reverse(io_list, &cc->write_thread_list, list) {
+ if ((long)(io_list->sequence - io->sequence) < 0) {
+ list_add(&io->list, &io_list->list);
+ goto added;
+ }
+ }
+ list_add(&io->list, &cc->write_thread_list);
wake_up_locked(&cc->write_thread_wait);
+added:
spin_unlock_irqrestore(&cc->write_thread_wait.lock, flags);
}
@@ -1272,6 +1304,7 @@ static void kcryptd_crypt_write_convert(
io->ctx.bio_out = clone;
io->ctx.iter_out = clone->bi_iter;
+ io->sequence = (unsigned long)atomic_long_inc_return(&io->cc->alloc_sequence) - 1;
sector += bio_sectors(clone);
@@ -1822,6 +1855,8 @@ static int crypt_ctr(struct dm_target *t
init_waitqueue_head(&cc->write_thread_wait);
INIT_LIST_HEAD(&cc->write_thread_list);
+ cc->write_sequence = 0;
+ atomic_long_set(&cc->alloc_sequence, 0);
cc->write_thread = kthread_create(dmcrypt_write, cc, "dmcrypt_write");
if (IS_ERR(cc->write_thread)) {
--
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