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dkim=pass header.d=Nvidia.com header.s=selector2 header.b=UP8QGTeR; spf=none (imf19.hostedemail.com: domain of ziy@nvidia.com has no SPF policy when checking 40.107.237.87) smtp.mailfrom=ziy@nvidia.com; dmarc=pass (policy=quarantine) header.from=nvidia.com X-HE-Tag: 1626788224-638645 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: --=_MailMate_7F5B83E3-998B-4F45-A611-699277F823EF_= Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 20 Jul 2021, at 2:55, Huang Ying wrote: > Before the commit c5b5a3dd2c1f ("mm: thp: refactor NUMA fault > handling"), the TLB flushing is done in do_huge_pmd_numa_page() itself > via flush_tlb_range(). > > But after commit c5b5a3dd2c1f ("mm: thp: refactor NUMA fault > handling"), the TLB flushing is done in migrate_pages() as in the > following code path anyway. > > do_huge_pmd_numa_page > migrate_misplaced_page > migrate_pages > > So now, the TLB flushing code in do_huge_pmd_numa_page() becomes > unnecessary. So the code is deleted in this patch to simplify the > code. This is only code cleanup, there's no visible performance > difference. But we save a potential TLB flush here right? Maybe the if statement is not a common case. Anyway, LGTM, Thanks. Reviewed-by: Zi Yan > > Signed-off-by: "Huang, Ying" > Cc: Yang Shi > Cc: Dan Carpenter > Cc: Mel Gorman > Cc: Christian Borntraeger > Cc: Gerald Schaefer > Cc: Heiko Carstens > Cc: Hugh Dickins > Cc: Andrea Arcangeli > Cc: Kirill A. Shutemov > Cc: Michal Hocko > Cc: Vasily Gorbik > Cc: Zi Yan > --- > mm/huge_memory.c | 26 -------------------------- > 1 file changed, 26 deletions(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index afff3ac87067..9f21e44c9030 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -1440,32 +1440,6 @@ vm_fault_t do_huge_pmd_numa_page(struct vm_fault= *vmf) > goto out; > } > > - /* > - * Since we took the NUMA fault, we must have observed the !accessibl= e > - * bit. Make sure all other CPUs agree with that, to avoid them > - * modifying the page we're about to migrate. > - * > - * Must be done under PTL such that we'll observe the relevant > - * inc_tlb_flush_pending(). > - * > - * We are not sure a pending tlb flush here is for a huge page > - * mapping or not. Hence use the tlb range variant > - */ > - if (mm_tlb_flush_pending(vma->vm_mm)) { > - flush_tlb_range(vma, haddr, haddr + HPAGE_PMD_SIZE); > - /* > - * change_huge_pmd() released the pmd lock before > - * invalidating the secondary MMUs sharing the primary > - * MMU pagetables (with ->invalidate_range()). The > - * mmu_notifier_invalidate_range_end() (which > - * internally calls ->invalidate_range()) in > - * change_pmd_range() will run after us, so we can't > - * rely on it here and we need an explicit invalidate. > - */ > - mmu_notifier_invalidate_range(vma->vm_mm, haddr, > - haddr + HPAGE_PMD_SIZE); > - } > - > pmd =3D pmd_modify(oldpmd, vma->vm_page_prot); > page =3D vm_normal_page_pmd(vma, haddr, pmd); > if (!page) > -- = > 2.30.2 =E2=80=94 Best Regards, Yan, Zi --=_MailMate_7F5B83E3-998B-4F45-A611-699277F823EF_= Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQJDBAEBCgAtFiEEh7yFAW3gwjwQ4C9anbJR82th+ooFAmD20XcPHHppeUBudmlk aWEuY29tAAoJEJ2yUfNrYfqKhHEP/RcrpAV0HutdZ/bePNQb+Nggiz2IDbslnAVF xovRDEf4FmTLoGHhEh2PNRwk+JdO1hVZuzxsRyzvwykH+5Wp+eJM+zVXPZUPrgw2 Sir+qON3uZzc4r8h4M+qF6svTcjbcBcaTIPKqR+4Q0ms8p2DcIoma8fNgy0+Q5WG bXLg+/J8ttpu2esXaLn9yYMXVgQptNr0qIsUwRnut4kU6txz/GO8pMZz+iPTvzVR +X8uLP/XkcU6bsO3livZ8y6x+ni7q/PrcGDQyJc1tOcISD84WBjG4zrwfyEgBqe8 N94MBTuSOKJP8u872e8yuJ9oUv+zKq7QYtVbWXEi81A0BaMZGeLP4o4iXTX25KOZ vadm047BtiVpkXmKV6D/FRq7tUQOTl97usp4SC/c6CGSYtkcS36RKnW/UTIcX8zz yQJhkQkrq9bRF8nVpfmzI/2sZfPMNkWtRjeHhQTcckd0/lF7gpw2F4+SoOdGUG/s XUqgjdE94OqwzDnABAE/35e2kj7u2KoOIU8oPHykixOk0SZaBSJVtXLOlwzPYNRW OwVqXwzScIW1Gj+csvRPWext3nu9/89EXsb3J3dSDlJ7t7Ocmo55qvrLJ9cfB/8D ZayIMIrWsYRMkQ4xuS8fHXrfVrFLJ9EzzjzUDSJb5JX0u21awqDXz4voMmrlTpHo npI7wSbS =Za01 -----END PGP SIGNATURE----- --=_MailMate_7F5B83E3-998B-4F45-A611-699277F823EF_=--