Hi, Ingo Molnar <mingo <at> elte.hu> writes: > * Linus Torvalds <torvalds <at> linux-foundation.org> wrote: > > On Fri, 3 Aug 2007, Peter Zijlstra wrote: > > > > > > These patches aim to improve balance_dirty_pages() and directly address > > > three issues: > > > 1) inter device starvation > > > 2) stacked device deadlocks > > > 3) inter process starvation > > > > Ok, the patches certainly look pretty enough, and you fixed the only > > thing I complained about last time (naming), so as far as I'm > > concerned it's now just a matter of whether it *works* or not. I guess > > being in -mm will help somewhat, but it would be good to have people > > with several disks etc actively test this out. > > There are positive reports in the never-ending "my system crawls like an > XT when copying large files" bugzilla entry: > > http://bugzilla.kernel.org/show_bug.cgi?id=7372 > >[ snipped part of the bug report ] > > so the whole problem area seems to be a "perfect storm" created by a > combination of TCQ, IO scheduling and VM dirty handling weaknesses. Per > device dirty throttling is a good step forward and it makes a very > visible positive difference.
Foreword: I'm the OP of bug #7372. I just want to say/add that: 1) I'm running the per-bdi patch since about 30 days on a master mysql server under somewhat mild load without any adverse effect I could notice. 2) I _still_ don't get the "performances" of 2.6.17, but since that's the better combination I could get, I think there is IMHO progress in the right direction (to be compared to no progress since 2.6.18, that's better :-)). To be honest, a vanilla 2.6.17 not tuned at all (ie vfs_cache_pressure and other knobs in /proc/sys/vm like swappiness and dirty_*) is still better than any other upcoming kernel I tested. Thus I still think 2.6.18 added a big regression (which unfortunately I couldn't find). Read the full bug report for any background information if needed. Unfortunately it isn't practical to git-bisect my issue as the server is a production server that can't be rebooted/stopped whenever I want (and since I found workarounds of the issue...). Thanks for showing interest in this issue. Please CC: me on any answers as I'm not subscribed to the list. -- Brice Figureau - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
