On Tue, Jan 15, 2008 at 04:13:22PM -0500, Mike Snitzer wrote: > On Jan 14, 2008 7:50 AM, Fengguang Wu <wfg@xxxxxxxxxxxxxxxx> wrote: > > On Mon, Jan 14, 2008 at 12:41:26PM +0100, Peter Zijlstra wrote: > > > > > > On Mon, 2008-01-14 at 12:30 +0100, Joerg Platte wrote: > > > > Am Montag, 14. Januar 2008 schrieb Fengguang Wu: > > > > > > > > > Joerg, this patch fixed the bug for me :-) > > > > > > > > Fengguang, congratulations, I can confirm that your patch fixed the bug! With > > > > previous kernels the bug showed up after each reboot. Now, when booting the > > > > patched kernel everything is fine and there is no longer any suspicious > > > > iowait! > > > > > > > > Do you have an idea why this problem appeared in 2.6.24? Did somebody change > > > > the ext2 code or is it related to the changes in the scheduler? > > > > > > It was Fengguang who changed the inode writeback code, and I guess the > > > new and improved code was less able do deal with these funny corner > > > cases. But he has been very good in tracking them down and solving them, > > > kudos to him for that work! > > > > Thank you. > > > > In particular the bug is triggered by the patch named: > > "writeback: introduce writeback_control.more_io to indicate more io" > > That patch means to speed up writeback, but unfortunately its > > aggressiveness has disclosed bugs in reiserfs, jfs and now ext2. > > > > Linus, given the number of bugs it triggered, I'd recommend revert > > this patch(git commit 2e6883bdf49abd0e7f0d9b6297fc3be7ebb2250b). Let's > > push it back to -mm tree for more testings? > > Fengguang, > > I'd like to better understand where your writeback work stands > relative to 2.6.24-rcX and -mm. To be clear, your changes in > 2.6.24-rc7 have been benchmarked to provide a ~33% sequential write > performance improvement with ext3 (as compared to 2.6.22, CFS could be > helping, etc but...). Very impressive! Wow, glad to hear that. > Given this improvement it is unfortunate to see your request to revert > 2e6883bdf49abd0e7f0d9b6297fc3be7ebb2250b but it is understandable if > you're not confident in it for 2.6.24. > > That said, you recently posted an -mm patchset that first reverts > 2e6883bdf49abd0e7f0d9b6297fc3be7ebb2250b and then goes on to address > the "slow writes for concurrent large and small file writes" bug: > http://lkml.org/lkml/2008/1/15/132 > > For those interested in using your writeback improvements in > production sooner rather than later (primarily with ext3); what > recommendations do you have? Just heavily test our own 2.6.24 + your > evolving "close, but not ready for merge" -mm writeback patchset? It's not ready mainly because it is fresh made and need more feedbacks. It's doing OK on my desktop :-) - To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
