Re: [PATCH 0/9] mm/madvise: batch tlb flushes for MADV_DONTNEED and MADV_FREE

Roman Gushchin
2025-03-10T23:36:59Z

On Mon, Mar 10, 2025 at 04:15:06PM -0700, Shakeel Butt wrote:
> On Mon, Mar 10, 2025 at 03:39:21PM -0700, Andrew Morton wrote:
> > On Mon, 10 Mar 2025 10:23:09 -0700 SeongJae Park <sj@kernel.org> wrote:
> >
> > > It is unclear if such use case
> > > is common and the inefficiency is significant.
> >
> > Well, we could conduct a survey,
> >
> > Can you add some logging to detect when userspace performs such an
> > madvise() call, then run that kernel on some "typical" machines which
> > are running "typical" workloads? That should give us a feeling for how
> > often userspace does this, and hence will help us understand the usefulness
> > of this patchset.
>
> Just for the clarification, this patchset is very useful for the
> process_madvise() and the experiment results show that.

+1

Google carried an internal version for a vectorized madvise() which
was much faster than process_madvise() last time I measured it.
I hope SJ's patchset will (partially) address this difference,
which will hopefully allow to drop the internal implementation
for process_madvise.