On Thu, Aug 3, 2023 at 5:27 PM Yin, Fengwei <fengwei.yin@xxxxxxxxx> wrote: > > > > On 8/4/2023 4:46 AM, Yu Zhao wrote: > > On Wed, Aug 2, 2023 at 6:56 AM Yin, Fengwei <fengwei.yin@xxxxxxxxx> wrote: > >> > >>" > >> > >> On 8/2/2023 8:49 PM, Ryan Roberts wrote: > >>> On 02/08/2023 13:42, Yin, Fengwei wrote: > >>>> > >>>> > >>>> On 8/2/2023 8:40 PM, Ryan Roberts wrote: > >>>>> On 02/08/2023 13:35, Yin, Fengwei wrote: > >>>>>> > >>>>>> > >>>>>> On 8/2/2023 6:27 PM, Ryan Roberts wrote: > >>>>>>> On 28/07/2023 17:13, Yin Fengwei wrote: > >>>>>>>> In madvise_cold_or_pageout_pte_range() and madvise_free_pte_range(), > >>>>>>>> folio_mapcount() is used to check whether the folio is shared. But it's > >>>>>>>> not correct as folio_mapcount() returns total mapcount of large folio. > >>>>>>>> > >>>>>>>> Use folio_estimated_sharers() here as the estimated number is enough. > >>>>>>>> > >>>>>>>> Yin Fengwei (2): > >>>>>>>> madvise: don't use mapcount() against large folio for sharing check > >>>>>>>> madvise: don't use mapcount() against large folio for sharing check > >>>>>>>> > >>>>>>>> mm/huge_memory.c | 2 +- > >>>>>>>> mm/madvise.c | 6 +++--- > >>>>>>>> 2 files changed, 4 insertions(+), 4 deletions(-) > >>>>>>>> > >>>>>>> > >>>>>>> As a set of fixes, I agree this is definitely an improvement, so: > >>>>>>> > >>>>>>> Reviewed-By: Ryan Roberts > >>>>>> Thanks. > >>>>>> > >>>>>>> > >>>>>>> > >>>>>>> But I have a couple of comments around further improvements; > >>>>>>> > >>>>>>> Once we have the scheme that David is working on to be able to provide precise > >>>>>>> exclusive vs shared info, we will probably want to move to that. Although that > >>>>>>> scheme will need access to the mm_struct of a process known to be mapping the > >>>>>>> folio. We have that info, but its not passed to folio_estimated_sharers() so we > >>>>>>> can't just reimplement folio_estimated_sharers() - we will need to rework these > >>>>>>> call sites again. > >>>>>> Yes. This could be extra work. Maybe should delay till David's work is done. > >>>>> > >>>>> What you have is definitely an improvement over what was there before. And is > >>>>> probably the best we can do without David's scheme. So I wouldn't delay this. > >>>>> Just pointing out that we will be able to make it even better later on (if > >>>>> David's stuff goes in). > >>>> Yes. I agree that we should wait for David's work ready and do fix based on that. > >>> > >>> I was suggesting the opposite - not waiting. Then we can do separate improvement > >>> later. > >> Let's wait for David's work ready. > > > > Waiting is fine as long as we don't miss the next merge window -- we > > don't want these two bugs to get into another release. Also I think we > > should cc stable, since as David mentioned, they have been causing > > selftest failures. > > Stable was CCed. Need to add the "Cc: stable@xxxxxxxxxxxxxxx" tag: Documentation/process/stable-kernel-rules.rst
