diff options
| author | Coly Li <colyli@suse.de> | 2018-12-13 22:53:53 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2018-12-13 08:15:54 -0700 |
| commit | 7a671d8ef821bf5743fdff17fae0600648345b03 (patch) | |
| tree | a4199a4a11b9fff8b6e02d7e6dad331991c091a9 /drivers/md/bcache/sysfs.c | |
| parent | cb07ad63682ffcce10e9beaed7828a26780e3df9 (diff) | |
bcache: option to automatically run gc thread after writeback
The option gc_after_writeback is disabled by default, because garbage
collection will discard SSD data which drops cached data.
Echo 1 into /sys/fs/bcache/<UUID>/internal/gc_after_writeback will
enable this option, which wakes up gc thread when writeback accomplished
and all cached data is clean.
This option is helpful for people who cares writing performance more. In
heavy writing workload, all cached data can be clean only happens when
writeback thread cleans all cached data in I/O idle time. In such
situation a following gc running may help to shrink bcache B+ tree and
discard more clean data, which may be helpful for future writing
requests.
If you are not sure whether this is helpful for your own workload,
please leave it as disabled by default.
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/md/bcache/sysfs.c')
| -rw-r--r-- | drivers/md/bcache/sysfs.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c index c09748497cdc..621186b4240f 100644 --- a/drivers/md/bcache/sysfs.c +++ b/drivers/md/bcache/sysfs.c @@ -128,6 +128,7 @@ rw_attribute(expensive_debug_checks); rw_attribute(cache_replacement_policy); rw_attribute(btree_shrinker_disabled); rw_attribute(copy_gc_enabled); +rw_attribute(gc_after_writeback); rw_attribute(size); static ssize_t bch_snprint_string_list(char *buf, @@ -693,6 +694,7 @@ SHOW(__bch_cache_set) sysfs_printf(gc_always_rewrite, "%i", c->gc_always_rewrite); sysfs_printf(btree_shrinker_disabled, "%i", c->shrinker_disabled); sysfs_printf(copy_gc_enabled, "%i", c->copy_gc_enabled); + sysfs_printf(gc_after_writeback, "%i", c->gc_after_writeback); sysfs_printf(io_disable, "%i", test_bit(CACHE_SET_IO_DISABLE, &c->flags)); @@ -793,6 +795,12 @@ STORE(__bch_cache_set) sysfs_strtoul(gc_always_rewrite, c->gc_always_rewrite); sysfs_strtoul(btree_shrinker_disabled, c->shrinker_disabled); sysfs_strtoul(copy_gc_enabled, c->copy_gc_enabled); + /* + * write gc_after_writeback here may overwrite an already set + * BCH_DO_AUTO_GC, it doesn't matter because this flag will be + * set in next chance. + */ + sysfs_strtoul_clamp(gc_after_writeback, c->gc_after_writeback, 0, 1); return size; } @@ -873,6 +881,7 @@ static struct attribute *bch_cache_set_internal_files[] = { &sysfs_gc_always_rewrite, &sysfs_btree_shrinker_disabled, &sysfs_copy_gc_enabled, + &sysfs_gc_after_writeback, &sysfs_io_disable, NULL }; |