On 2/26/21 4:57 PM, Norman.Kern wrote: > [snipped] >> You may try to trigger a gc by writing to >> sys/fs/bcache/<cache-set-uuid>/internal/trigger_gc >> > When all cache had written back, I triggered gc, it recalled. > > root@WXS0106:~# cat /sys/block/bcache0/bcache/cache/cache_available_percent > 30 > > root@WXS0106:~# echo 1 > /sys/block/bcache0/bcache/cache/internal/trigger_gc > root@WXS0106:~# cat /sys/block/bcache0/bcache/cache/cache_available_percent > 97 > > Why must I trigger gc manually? Is not a default action of bcache-gc thread? And I found it can only work when all dirty data written back. > 1, GC is automatically triggered after some mount of data consumed. I guess it is just not about time in your situation. 2, Because the gc will shrink all cached clean data, which is very unfriendly for read-intend workload. Therefore gc_after_writeback is defaulted as 0, when this sysfs file content set to 1, a gc will trigger after the writeback accomplished. Coly Li
