On Wed, Mar 10, 2021 at 2:41 PM Shakeel Butt <[email protected]> wrote: > > On Wed, Mar 10, 2021 at 1:41 PM Yang Shi <[email protected]> wrote: > > > > On Wed, Mar 10, 2021 at 1:08 PM Shakeel Butt <[email protected]> wrote: > > > > > > On Wed, Mar 10, 2021 at 10:54 AM Yang Shi <[email protected]> wrote: > > > > > > > > On Wed, Mar 10, 2021 at 10:24 AM Shakeel Butt <[email protected]> > > > > wrote: > > > > > > > > > > On Wed, Mar 10, 2021 at 9:46 AM Yang Shi <[email protected]> wrote: > > > > > > > > > > > > The number of deferred objects might get windup to an absurd > > > > > > number, and it > > > > > > results in clamp of slab objects. It is undesirable for sustaining > > > > > > workingset. > > > > > > > > > > > > So shrink deferred objects proportional to priority and cap > > > > > > nr_deferred to twice > > > > > > of cache items. > > > > > > > > > > > > The idea is borrowed from Dave Chinner's patch: > > > > > > https://lore.kernel.org/linux-xfs/[email protected]/ > > > > > > > > > > > > Tested with kernel build and vfs metadata heavy workload in our > > > > > > production > > > > > > environment, no regression is spotted so far. > > > > > > > > > > Did you run both of these workloads in the same cgroup or separate > > > > > cgroups? > > > > > > > > Both are covered. > > > > > > > > > > Have you tried just this patch i.e. without the first 12 patches? > > > > No. It could be applied without the first 12 patches, but I didn't > > test this combination specifically since I don't think it would have > > any difference from with the first 12 patches. I tested running the > > test case under root memcg, it seems equal to w/o the first 12 patches > > and the only difference is where to get nr_deferred. > > I am trying to measure the impact of this patch independently. One > point I can think of is the global reclaim. The first 12 patches do > not aim to improve the global reclaim but this patch will. I am just > wondering what would be negative if any of this patch.
Feel free to do so. More tests from more workloads are definitely appreciated. That could give us more confidence about this patch or catch regression sooner.
