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authorTang Junhui <tang.junhui@zte.com.cn>2017-09-06 14:25:55 +0800
committerJens Axboe <axboe@kernel.dk>2017-09-06 08:17:33 -0600
commit0b43f49dc4d6d3789e936731dc16af94cb57d568 (patch)
tree318ac8d254a2560f7ccb1401a3a105308362925f /drivers/md
parent09b3efec81def807fb225359e34a8e72866dd9c4 (diff)
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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 <tang.junhui@zte.com.cn> Reviewed-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/bcache/sysfs.c15
1 files changed, 14 insertions, 1 deletions
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;