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charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: B6D59140010 X-Rspam-User: X-Stat-Signature: cbq6tx16zcbgea4rdmbpwmfcjwhx31oy X-HE-Tag: 1682328342-268822 X-HE-Meta: U2FsdGVkX18BYilE2H3nv0phHD91q6dpsLigRD7pq3QsYRtTMBqr1mOXBvuONQLHlrHBkg0LWB/oFTfJh3AI3TucG6fbFBNP8TV5JnLgGhVo0DuRUWK6GDxDOGfivMMtm1gpEyB2cMse6ryFB96Mo5vFyKTecaEFWAYNKyR8M7b398ExtvfCKZDLStkq4U+qdTRzsORpsQZ3BOw9DZdQX2XrrDoiefjkSrTHfxVb5q6308EYkL7hM5DkAmx3ww4wCvQSFQYZ6vYevZkOhEBCTBvWyI5Rgd2x74QxQqKlV72y1mQ79Y33CvG+mn4gn6zAv/56NGDrNr5C5nDLm0Da88uEX1tJAphZhcqHIZVbkiEijHEqKNU46fnQ/UzXN0HccnD9do0aWVM/Wl6CO2bVfEo+SpHUmETEdCwlUqxhCdttPH9t5d6q1+hE8EzzilaTd/81abxplGKb6lCGpQiHuIm8PWpgwvUbRLiB76F4Qc8KflkVNB/9mchqoVSxj38XvR58vwcW380USOSAKNjLAVka+jm6Ij1O7BwKwZB954/T54KzhFbBDbvFDiWEklD/zUendnEJr8HqexzQUMHrUI7NxklYur5QOUSqdaYdkYrvncKT2pD7Ac5ZuQ80dQ/n9u9pFs1/i0JQtqpsLoGMI3zCQNQuMNxJ/v/RpSYu2iHyAl6CGGdNP6/qkQ3FfRK1su01qG7+AzGaNpN8cwvHdHqaCcwSNZSkmcq0gUTzlOgyQu6yK2+CsiCrndhYVRBkfsnvnUVAqM3lYjPFF7Etmqap0vgMuKDv5Mpmi3htsc5VpernktsaquxOKMiFb1s1bAKxICXlXTpEDKRU3QTK3nahrx2OgDRJq3T1iTP5aBJx8Bh8PTGpVWisuWuySqBrNErUu3+Y1I+OlXGrcokA1m71CtBGyS60rQIDcC+P7p88y8lylm5g7DZUXDetrFzP+zSdbuyTokQcoPeKoLS GM4qCgiu RkY+RljhpftCGpPzJATZCjBBykpDGaKg9gb+1aO14wjwuHbp5ZlLDLofxb/bJqTYP0BNtXhY6Oy5tFhshPqL1Fq/TGekOXF+KOgfNhp7QNAUzReydilGpd4fhSs+blpyWbt4VMDQbP2H8ZvrZndwA3s9pwimLePu3ktiD4I+j62xiJlSP/aMpR7h72xV8ZQXVJhrExYZ0uexPBt/SLaP9dY9/Uph6ewMWUNgdGDMOKdAqmS/Xf6UhOTnM3oJm/1YFxqF3KxrX3rgcT8/foD60FphNzYXqZ7kyJxdz4H14ZOQXkYsIL8kYknQ8IdcbnI5YFPIbjtR1/iTM3bcU41JnGLTA9P8JRF0aj4oxtC74ki7da8FY/yXcXLJIEhvE5aArl9u2 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 在 2023/4/24 下午2:54, Huang Ying 写道: > Hi, Andrew, > > The version 1 of this patch was merged in mm-unstable branch. If you > want to move that patch into mm-stable recently, it may be better to > update that patch with this new version firstly. If you want to do > that after v6.4-rc1, I will rebase this patch and resend it after > v6.4-rc1 is released. > > Hi, Amit, > > The patch has been changed based on comments from Xin. I keep your > "reviewed-by" because I think the change is trivial. But if you think > it's inappropriate, I will change that. > > Best Regards, > Huang, Ying > > ------------------------------->8------------------------------------------ > 0Day/LKP reported a performance regression for commit > 7e12beb8ca2a ("migrate_pages: batch flushing TLB"). In the commit, the > TLB flushing during page migration is batched. So, in > try_to_migrate_one(), ptep_clear_flush() is replaced with > set_tlb_ubc_flush_pending(). In further investigation, it is found > that the TLB flushing can be avoided in ptep_clear_flush() if the PTE > is inaccessible. In fact, we can optimize in similar way for the > batched TLB flushing too to improve the performance. > > So in this patch, we check pte_accessible() before > set_tlb_ubc_flush_pending() in try_to_unmap/migrate_one(). Tests show > that the benchmark score of the anon-cow-rand-mt test case of > vm-scalability test suite can improve up to 2.1% with the patch on a > Intel server machine. The TLB flushing IPI can reduce up to 44.3%. > > Link: https://lore.kernel.org/oe-lkp/202303192325.ecbaf968-yujie.liu@intel.com > Link: https://lore.kernel.org/oe-lkp/ab92aaddf1b52ede15e2c608696c36765a2602c1.camel@intel.com/ > Fixes: 7e12beb8ca2a ("migrate_pages: batch flushing TLB") > Reported-by: kernel test robot > Signed-off-by: "Huang, Ying" > Reviewed-by: Nadav Amit > Cc: haoxin > Cc: Mel Gorman > Cc: Hugh Dickins > Cc: Matthew Wilcox (Oracle) > Cc: David Hildenbrand > --- > mm/rmap.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/mm/rmap.c b/mm/rmap.c > index 8632e02661ac..be19232e94f4 100644 > --- a/mm/rmap.c > +++ b/mm/rmap.c > @@ -641,10 +641,14 @@ void try_to_unmap_flush_dirty(void) > #define TLB_FLUSH_BATCH_PENDING_LARGE \ > (TLB_FLUSH_BATCH_PENDING_MASK / 2) > > -static void set_tlb_ubc_flush_pending(struct mm_struct *mm, bool writable) > +static void set_tlb_ubc_flush_pending(struct mm_struct *mm, pte_t pteval) > { > struct tlbflush_unmap_batch *tlb_ubc = ¤t->tlb_ubc; > int batch, nbatch; > + bool writable = pte_dirty(pteval); > + > + if (!pte_accessible(mm, pteval)) > + return; LGTM Reviewed-by: Xin Hao > > arch_tlbbatch_add_mm(&tlb_ubc->arch, mm); > tlb_ubc->flush_required = true; > @@ -731,7 +735,7 @@ void flush_tlb_batched_pending(struct mm_struct *mm) > } > } > #else > -static void set_tlb_ubc_flush_pending(struct mm_struct *mm, bool writable) > +static void set_tlb_ubc_flush_pending(struct mm_struct *mm, pte_t pteval) > { > } > > @@ -1582,7 +1586,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, > */ > pteval = ptep_get_and_clear(mm, address, pvmw.pte); > > - set_tlb_ubc_flush_pending(mm, pte_dirty(pteval)); > + set_tlb_ubc_flush_pending(mm, pteval); > } else { > pteval = ptep_clear_flush(vma, address, pvmw.pte); > } > @@ -1963,7 +1967,7 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma, > */ > pteval = ptep_get_and_clear(mm, address, pvmw.pte); > > - set_tlb_ubc_flush_pending(mm, pte_dirty(pteval)); > + set_tlb_ubc_flush_pending(mm, pteval); > } else { > pteval = ptep_clear_flush(vma, address, pvmw.pte); > }