Hi there, I've been playing around with writeback mode in dmcache with my shiny new 3.9-rc1 kernel. # dmsetup table moocache 0 67108864 cache 253:0 253:1 8:0 512 1 writeback default 4 random_threshold 8 sequential_threshold 512 # dmsetup status moocache 0 67108864 cache 14/2048 3967 54586 263549 190982 0 0 2000 51 0 2 migration_threshold 204800 4 random_threshold 8 sequential_threshold 512 I think this means there are 51 dirty cache blocks? I'd like to flush them out to the spinny disk: # dmsetup suspend moocache # echo '0 67108864 cache 253:0 253:1 8:0 512 0 cleaner 0' | dmsetup reload moocache # dmsetup resume moocache Ok, now let's wait for it to finish... # dmsetup wait moocache # dmsetup status moocache 0 67108864 cache 14/2048 3967 54586 263583 190982 0 0 2000 0 0 2 migration_threshold 204800 0 Now that dirty field goes from 51 back to 0, like I'd expected. However, if I then put the old policy back: # dmsetup suspend moocache # echo '0 67108864 cache 253:0 253:1 8:0 512 1 writeback default 4 random_threshold 8 sequential_threshold 512' | dmsetup reload moocache # dmsetup resume moocache # dmsetup status moocache 0 67108864 cache 14/2048 3967 54586 263553 190982 0 0 2000 51 0 2 migration_threshold 204800 4 random_threshold 8 sequential_threshold 512 That's odd, there are still 51 dirty cache blocks? Am I missing something? Is there something about suspend/resume that causes something to get reset? Do I even need the suspend/resume pair? (I'm pretty sure I do; the table doesn't change if I don't.) I get the same dirtyblocks==51 results even if I remove and (re)create moocache. --D -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
