[PATCH 05/12] bcache: gc does not work when triggering by manual command
From: Coly Li <hidden>
Date: 2017-09-06 06:25:55
Also in:
linux-bcache
Subsystem:
bcache (block layer cache), the rest · Maintainers:
Coly Li, Kent Overstreet, Linus Torvalds
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. (Code comments aded by Coly Li) Signed-off-by: Tang Junhui <redacted> Reviewed-by: Coly Li <redacted> --- drivers/md/bcache/sysfs.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
index f90f13616980..09295c07ea88 100644
--- a/drivers/md/bcache/sysfs.c
+++ b/drivers/md/bcache/sysfs.c@@ -615,8 +615,21 @@ STORE(__bch_cache_set) bch_cache_accounting_clear(&c->accounting); } - if (attr == &sysfs_trigger_gc) + if (attr == &sysfs_trigger_gc) { + /* + * Garbage collection thread only works when sectors_to_gc < 0, + * when users write to sysfs entry trigger_gc, most of time + * they want to forcibly triger gargage collection. Here -1 is + * set to c->sectors_to_gc, to make gc_should_run() give a + * chance to permit gc thread to run. "give a chance" means + * before going into gc_should_run(), there is still chance + * that c->sectors_to_gc being set to other positive value. So + * writing sysfs entry trigger_gc won't always make sure gc + * thread takes effect. + */ + atomic_set(&c->sectors_to_gc, -1); wake_up_gc(c); + } if (attr == &sysfs_prune_cache) { struct shrink_control sc;
--
2.13.5