Re: [PATCH] [PATCH v3] bcache: gc does not work when triggering by manual
From: Coly Li <hidden>
Date: 2017-10-10 06:12:16
Also in:
linux-bcache
On 2017/10/10 上午10:44, tang.junhui@zte.com.cn wrote:
From: Tang Junhui <redacted> I try to execute the following command to trigger gc thread: [root@localhost internal]# echo 1 > trigger_gc But it does not work, I debug the code in gc_should_run(), It works only if in invalidating or sectors_to_gc < 0. So set sectors_to_gc to -1 to meet the condition when we trigger gc by manual command. Signed-off-by: Tang Junhui <redacted>
Hi Junhui,
This patch is in mainline kernel v4.14 already, there is the upstream
patch head,
commit 0b43f49dc4d6d3789e936731dc16af94cb57d568
Author: Tang Junhui [off-list ref]
Date: Wed Sep 6 14:25:55 2017 +0800
bcache: gc does not work when triggering by manual command
I try to execute the following command to trigger gc thread:
[root@localhost internal]# echo 1 > trigger_gc
But it does not work, I debug the code in gc_should_run(), It works only
if in invalidating or sectors_to_gc < 0. So set sectors_to_gc to -1 to
meet the condition when we trigger gc by manual command.
(Code comments aded by Coly Li)
Signed-off-by: Tang Junhui [off-list ref]
Reviewed-by: Coly Li [off-list ref]
Signed-off-by: Jens Axboe [off-list ref]
quoted hunk ↗ jump to hunk
--- drivers/md/bcache/sysfs.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c index b3ff57d..bef776d 100644 --- a/drivers/md/bcache/sysfs.c +++ b/drivers/md/bcache/sysfs.c@@ -614,8 +614,16 @@ STORE(__bch_cache_set) bch_cache_accounting_clear(&c->accounting); } - if (attr == &sysfs_trigger_gc) + if (attr == &sysfs_trigger_gc) { + /* + * Satisfy the gc condition by setting sectors_to_gc under 0, + * sectors_to_gc may also be decreased under 0 in + * bch_data_insert_start() and gc would be triggered again, + * but the race is rare, and harmless, so we can ignore it + */ + atomic_set(&c->sectors_to_gc, -1); wake_up_gc(c); + } if (attr == &sysfs_prune_cache) { struct shrink_control sc;
-- Coly Li