Messages in this thread | | | Date | Sat, 9 Feb 2019 08:25:31 +1100 | From | Dave Chinner <> | Subject | Re: [PATCH 1/2] Revert "mm: don't reclaim inodes with many attached pages" |
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On Thu, Feb 07, 2019 at 09:37:27PM -0800, Andrew Morton wrote: > On Thu, 7 Feb 2019 11:27:50 +0100 Jan Kara <jack@suse.cz> wrote: > > > On Fri 01-02-19 09:19:04, Dave Chinner wrote: > > > Maybe for memcgs, but that's exactly the oppose of what we want to > > > do for global caches (e.g. filesystem metadata caches). We need to > > > make sure that a single, heavily pressured cache doesn't evict small > > > caches that lower pressure but are equally important for > > > performance. > > > > > > e.g. I've noticed recently a significant increase in RMW cycles in > > > XFS inode cache writeback during various benchmarks. It hasn't > > > affected performance because the machine has IO and CPU to burn, but > > > on slower machines and storage, it will have a major impact. > > > > Just as a data point, our performance testing infrastructure has bisected > > down to the commits discussed in this thread as the cause of about 40% > > regression in XFS file delete performance in bonnie++ benchmark. > > > > Has anyone done significant testing with Rik's maybe-fix?
Apart from pointing out all the bugs and incorrect algorithmic assumptions it makes, no.
Cheers,
Dave. -- Dave Chinner david@fromorbit.com
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