On Tuesday 12 August 2008 16:29, FUJITA Tomonori wrote: > On Wed, 13 Aug 2008 08:24:41 +0900 > FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx> wrote: > > > On Tue, 12 Aug 2008 12:00:36 -0700 > > Daniel Phillips <phillips@xxxxxxxxx> wrote: > > > > > On Tuesday 12 August 2008 06:14, FUJITA Tomonori wrote: > > > > > You just want to use getblk for alloc_chunk_buffer, > > > > > not vmalloc. > > > > > > > > I think that it means that we cache all the chunks, both btree chunks > > > > and the data chunks (which are passed to the upper layer such as file > > > > systems). I think that we don't want cache the latter in dm. > > > > > > That is true. However your code should not be reading data chunks into > > > memory at all. The only time the snapshot code has to read a data > > > chunk is when performing the copy from origin to snapshot store in > > > make_unique. Your code does not directly perform this task as far as I > > > can see. That would be done in a part of the dm snapshot code your > > > patch does not touch, which I seem to recall uses the kcopyd mechanism. > > > > Yes, dm-snapshot doesn't access to data chunks. However, dm does for > > dm-snapshot (by using submit_bio friends). So if dm-snapshot uses > > __getblk, we use both __getblk and submit_bio with a single device at > > the same time. I think that it's the right thing. > > Oops, I meant, I don't think that it's the right thing. Sure, it is perfectly ok. Regards, Daniel -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
