diff options
| author |   Christoph Hellwig <hch@lst.de> | 2015-10-05 09:31:09 +0200 |
|---|---|---|
| committer |   NeilBrown <neilb@suse.com> | 2015-11-01 13:48:28 +1100 |
| commit | 56fef7c6e02493dce316de99a11e9e26b852218b (patch) | |
| tree | 947aafd77670967d989849453b1d2c24d96dbfdf /drivers/md | |
| parent | raid5-cache: factor out a helper to run all stripes for an I/O unit (diff) | |
| download | linux-dev-56fef7c6e02493dce316de99a11e9e26b852218b.tar.xz linux-dev-56fef7c6e02493dce316de99a11e9e26b852218b.zip | |
raid5-cache: simplify state machine when caches flushes are not needed
For devices without a volatile write cache we don't need to send a FLUSH
command to ensure writes are stable on disk, and thus can avoid the whole
step of batching up bios for processing by the MD thread.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/raid5-cache.c | 33 |
1 files changed, 29 insertions, 4 deletions
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c index a81db0a8466a..a7ee7ec89f4f 100644 --- a/drivers/md/raid5-cache.c +++ b/drivers/md/raid5-cache.c @@ -83,6 +83,8 @@ struct r5l_log { struct list_head no_space_stripes; /* pending stripes, log has no space */ spinlock_t no_space_stripes_lock; + + bool need_cache_flush; }; /* @@ -206,6 +208,22 @@ static void r5l_io_run_stripes(struct r5l_io_unit *io) } /* XXX: totally ignores I/O errors */ +static void r5l_log_run_stripes(struct r5l_log *log) +{ + struct r5l_io_unit *io, *next; + + assert_spin_locked(&log->io_list_lock); + + list_for_each_entry_safe(io, next, &log->running_ios, log_sibling) { + /* don't change list order */ + if (io->state < IO_UNIT_IO_END) + break; + + list_move_tail(&io->log_sibling, &log->finished_ios); + r5l_io_run_stripes(io); + } +} + static void r5l_log_endio(struct bio *bio) { struct r5l_io_unit *io = bio->bi_private; @@ -219,11 +237,15 @@ static void r5l_log_endio(struct bio *bio) spin_lock_irqsave(&log->io_list_lock, flags); __r5l_set_io_unit_state(io, IO_UNIT_IO_END); - r5l_move_io_unit_list(&log->running_ios, &log->io_end_ios, - IO_UNIT_IO_END); + if (log->need_cache_flush) + r5l_move_io_unit_list(&log->running_ios, &log->io_end_ios, + IO_UNIT_IO_END); + else + r5l_log_run_stripes(log); spin_unlock_irqrestore(&log->io_list_lock, flags); - md_wakeup_thread(log->rdev->mddev->thread); + if (log->need_cache_flush) + md_wakeup_thread(log->rdev->mddev->thread); } static void r5l_submit_current_io(struct r5l_log *log) @@ -620,7 +642,8 @@ static void r5l_log_flush_endio(struct bio *bio) void r5l_flush_stripe_to_raid(struct r5l_log *log) { bool do_flush; - if (!log) + + if (!log || !log->need_cache_flush) return; spin_lock_irq(&log->io_list_lock); @@ -1065,6 +1088,8 @@ int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev) return -ENOMEM; log->rdev = rdev; + log->need_cache_flush = (rdev->bdev->bd_disk->queue->flush_flags != 0); + log->uuid_checksum = crc32c_le(~0, rdev->mddev->uuid, sizeof(rdev->mddev->uuid)); |