On Thu, Jan 31, 2019 at 03:48:11PM +0000, Chris Mason wrote: > On 30 Jan 2019, at 20:34, Dave Chinner wrote: > > > On Wed, Jan 30, 2019 at 12:21:07PM +0000, Chris Mason wrote: > >> > >> > >> On 29 Jan 2019, at 23:17, Dave Chinner wrote: > >> > >>> From: Dave Chinner <dchinner@xxxxxxxxxx> > >>> > >>> This reverts commit a76cf1a474d7dbcd9336b5f5afb0162baa142cf0. > >>> > >>> This change causes serious changes to page cache and inode cache > >>> behaviour and balance, resulting in major performance regressions > >>> when combining worklaods such as large file copies and kernel > >>> compiles. > >>> > >>> https://bugzilla.kernel.org/show_bug.cgi?id=202441 > >> > >> I'm a little confused by the latest comment in the bz: > >> > >> https://bugzilla.kernel.org/show_bug.cgi?id=202441#c24 > > > > Which says the first patch that changed the shrinker behaviour is > > the underlying cause of the regression. > > > >> Are these reverts sufficient? > > > > I think so. > > Based on the latest comment: > > "If I had been less strict in my testing I probably would have > discovered that the problem was present earlier than 4.19.3. Mr Gushins > commit made it more visible. > I'm going back to work after two days off, so I might not be able to > respond inside your working hours, but I'll keep checking in on this as > I get a chance." > > I don't think the reverts are sufficient. Roger has tested the two reverts more heavily against 5.0.0-rc3. Without the reverts, the machine locks up hard. With the two reverts applied, it runs along smoothly under extremely heavy load. https://bugzilla.kernel.org/show_bug.cgi?id=202441#c26 So, yes, these changes need to be reverted. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx
