bcache: gc does not work when triggering by manual command (0b43f49d) · Commits · 戴 / test

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>

drivers/md/bcache/sysfs.c

+14 −1

Original line number	Diff line number	Diff line
		@@ -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;

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