On Tue, 27 Jul 2010 23:13:58 -0400 Vivek Goyal <vgoyal@xxxxxxxxxx> wrote: > > > So the idea is that when a page is allocated, also store the blk_group > > > id and once that page is submitted for writeback, we should be able > > > to associate it to right blkio group? > > > > > blk_cgroup id can be attached whenever you wants. please overwrite > > page_cgroup->blk_cgroup when it's necessary. > > > Did you read Ikeda's patch ? I myself doesn't have patches at this point. > > This is just for make a room for recording blkio-ID, which was requested > > for a year. > > I have not read his patches yet. IIRC, previously there were issues > regarding which group should be charged for the page. The person who > allocated it or the thread which did last write to it etc... I guess > we can sort that out later. > > > > > Hmm, but page-allocation-time doesn't sound very good for me. > > > > Why? > As you wrote, by attaching ID when a page cache is added, we'll have much chances of free-rider until it's paged out. So, adding some reseting-owner point may be good. But considering real world usage, I may be wrong. There will not be much free rider in real world, especially at write(). Then, page-allocation time may be good. (Because database doesn't use page-cache, there will be no big random write application.) Thanks, -Kame -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>