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Groups > linux.kernel > #1709618
| From | Peter Zijlstra <peterz@infradead.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v6 6/7] mm: fix MADV_[FREE|DONTNEED] TLB flush miss problem |
| Date | 2017-08-11 15:40 +0200 |
| Message-ID | <udikp-47p-13@gated-at.bofh.it> (permalink) |
| References | <u9Wq6-6U6-5@gated-at.bofh.it> <u9Wq6-6U6-11@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Tue, Aug 01, 2017 at 05:08:17PM -0700, Nadav Amit wrote:
> void tlb_finish_mmu(struct mmu_gather *tlb,
> unsigned long start, unsigned long end)
> {
> - arch_tlb_finish_mmu(tlb, start, end);
> + /*
> + * If there are parallel threads are doing PTE changes on same range
> + * under non-exclusive lock(e.g., mmap_sem read-side) but defer TLB
> + * flush by batching, a thread has stable TLB entry can fail to flush
> + * the TLB by observing pte_none|!pte_dirty, for example so flush TLB
> + * forcefully if we detect parallel PTE batching threads.
> + */
> + bool force = mm_tlb_flush_nested(tlb->mm);
> +
> + arch_tlb_finish_mmu(tlb, start, end, force);
> }
I don't understand the comment nor the ordering. What guarantees we see
the increment if we need to?
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[PATCH v6 6/7] mm: fix MADV_[FREE|DONTNEED] TLB flush miss problem Nadav Amit <namit@vmware.com> - 2017-08-02 09:40 +0200
Re: [lkp-robot] [mm] 7674270022: will-it-scale.per_process_ops -19.3% regression Minchan Kim <minchan@kernel.org> - 2017-08-08 04:30 +0200
Re: [lkp-robot] [mm] 7674270022: will-it-scale.per_process_ops -19.3% regression Nadav Amit <nadav.amit@gmail.com> - 2017-08-08 06:30 +0200
Re: [lkp-robot] [mm] 7674270022: will-it-scale.per_process_ops -19.3% regression Nadav Amit <nadav.amit@gmail.com> - 2017-08-08 08:00 +0200
Re: [lkp-robot] [mm] 7674270022: will-it-scale.per_process_ops -19.3% regression Minchan Kim <minchan@kernel.org> - 2017-08-08 10:10 +0200
Re: [lkp-robot] [mm] 7674270022: will-it-scale.per_process_ops -19.3% regression Ye Xiaolong <xiaolong.ye@intel.com> - 2017-08-09 03:30 +0200
Re: [lkp-robot] [mm] 7674270022: will-it-scale.per_process_ops -19.3% regression Ye Xiaolong <xiaolong.ye@intel.com> - 2017-08-09 05:10 +0200
Re: [lkp-robot] [mm] 7674270022: will-it-scale.per_process_ops -19.3% regression Minchan Kim <minchan@kernel.org> - 2017-08-10 06:20 +0200
Re: [lkp-robot] [mm] 7674270022: will-it-scale.per_process_ops -19.3% regression Nadav Amit <nadav.amit@gmail.com> - 2017-08-10 06:20 +0200
Re: [lkp-robot] [mm] 7674270022: will-it-scale.per_process_ops -19.3% regression Minchan Kim <minchan@kernel.org> - 2017-08-10 06:30 +0200
Re: [PATCH v6 6/7] mm: fix MADV_[FREE|DONTNEED] TLB flush miss problem Peter Zijlstra <peterz@infradead.org> - 2017-08-11 15:40 +0200
Re: [PATCH v6 6/7] mm: fix MADV_[FREE|DONTNEED] TLB flush miss problem Nadav Amit <namit@vmware.com> - 2017-08-13 08:20 +0200
Re: [PATCH v6 6/7] mm: fix MADV_[FREE|DONTNEED] TLB flush miss problem Peter Zijlstra <peterz@infradead.org> - 2017-08-13 14:10 +0200
Re: [PATCH v6 6/7] mm: fix MADV_[FREE|DONTNEED] TLB flush miss problem Minchan Kim <minchan@kernel.org> - 2017-08-14 03:30 +0200
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