From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C5701C433EF for ; Tue, 21 Jun 2022 20:45:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352845AbiFUUpZ (ORCPT ); Tue, 21 Jun 2022 16:45:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43208 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236071AbiFUUpY (ORCPT ); Tue, 21 Jun 2022 16:45:24 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E9B311EC79 for ; Tue, 21 Jun 2022 13:45:23 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 86409617DA for ; Tue, 21 Jun 2022 20:45:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CAB6AC3411C; Tue, 21 Jun 2022 20:45:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1655844322; bh=I3X48bWDWkTdKOCet3xFNAxtZsRSa6yu2EXNrtIDkHY=; h=Date:To:From:Subject:From; b=yZOMxVNLCuFkE775W6FoHRe2WwYleu8FmcvgvrzlLLR/wr7uyWYCO0y384TChbU0b Gx2YeE3esQr1t3bFDFwguAEPjyJoDGnMbp/vusS9JIsA3HdNIYiDr3N9RUvl8aoIRj iNS9qSrrhJvEIcatYXZEHzsmNu1N5tRBAYc08Ae0= Date: Tue, 21 Jun 2022 13:45:13 -0700 To: mm-commits@vger.kernel.org, songmuchun@bytedance.com, mike.kravetz@oracle.com, baolin.wang@linux.alibaba.com, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-rmap-simplify-the-hugetlb-handling-when-unmapping-or-migration.patch added to mm-unstable branch Message-Id: <20220621204520.CAB6AC3411C@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm: rmap: simplify the hugetlb handling when unmapping or migration has been added to the -mm mm-unstable branch. Its filename is mm-rmap-simplify-the-hugetlb-handling-when-unmapping-or-migration.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-rmap-simplify-the-hugetlb-handling-when-unmapping-or-migration.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Baolin Wang Subject: mm: rmap: simplify the hugetlb handling when unmapping or migration Date: Mon, 20 Jun 2022 19:47:15 +0800 According to previous discussion [1], there are so many levels of indenting to handle the hugetlb case when unmapping or migration. We can combine folio_test_anon() and huge_pmd_unshare() to save one level of indenting, by adding a local variable and moving the VM_BUG_ON() a little forward. No intended functional changes in this patch. [1] https://lore.kernel.org/all/0b986dc4-5843-3e2d-c2df-5a2e9f13e6ab@oracle.com/ Link: https://lkml.kernel.org/r/28414b1b96f095e838c1e548074f8e0fc70d78cf.1655724713.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang Cc: Mike Kravetz Cc: Muchun Song Signed-off-by: Andrew Morton --- mm/rmap.c | 90 +++++++++++++++++++++++++--------------------------- 1 file changed, 44 insertions(+), 46 deletions(-) --- a/mm/rmap.c~mm-rmap-simplify-the-hugetlb-handling-when-unmapping-or-migration +++ a/mm/rmap.c @@ -1537,6 +1537,8 @@ static bool try_to_unmap_one(struct foli PageAnonExclusive(subpage); if (folio_test_hugetlb(folio)) { + bool anon = folio_test_anon(folio); + /* * The try_to_unmap() is only passed a hugetlb page * in the case where the hugetlb page is poisoned. @@ -1551,31 +1553,28 @@ static bool try_to_unmap_one(struct foli */ flush_cache_range(vma, range.start, range.end); - if (!folio_test_anon(folio)) { + /* + * To call huge_pmd_unshare, i_mmap_rwsem must be + * held in write mode. Caller needs to explicitly + * do this outside rmap routines. + */ + VM_BUG_ON(!anon && !(flags & TTU_RMAP_LOCKED)); + if (!anon && huge_pmd_unshare(mm, vma, &address, pvmw.pte)) { + flush_tlb_range(vma, range.start, range.end); + mmu_notifier_invalidate_range(mm, range.start, + range.end); + /* - * To call huge_pmd_unshare, i_mmap_rwsem must be - * held in write mode. Caller needs to explicitly - * do this outside rmap routines. + * The ref count of the PMD page was dropped + * which is part of the way map counting + * is done for shared PMDs. Return 'true' + * here. When there is no other sharing, + * huge_pmd_unshare returns false and we will + * unmap the actual page and drop map count + * to zero. */ - VM_BUG_ON(!(flags & TTU_RMAP_LOCKED)); - - if (huge_pmd_unshare(mm, vma, &address, pvmw.pte)) { - flush_tlb_range(vma, range.start, range.end); - mmu_notifier_invalidate_range(mm, range.start, - range.end); - - /* - * The ref count of the PMD page was dropped - * which is part of the way map counting - * is done for shared PMDs. Return 'true' - * here. When there is no other sharing, - * huge_pmd_unshare returns false and we will - * unmap the actual page and drop map count - * to zero. - */ - page_vma_mapped_walk_done(&pvmw); - break; - } + page_vma_mapped_walk_done(&pvmw); + break; } pteval = huge_ptep_clear_flush(vma, address, pvmw.pte); } else { @@ -1906,6 +1905,8 @@ static bool try_to_migrate_one(struct fo PageAnonExclusive(subpage); if (folio_test_hugetlb(folio)) { + bool anon = folio_test_anon(folio); + /* * huge_pmd_unshare may unmap an entire PMD page. * There is no way of knowing exactly which PMDs may @@ -1915,31 +1916,28 @@ static bool try_to_migrate_one(struct fo */ flush_cache_range(vma, range.start, range.end); - if (!folio_test_anon(folio)) { + /* + * To call huge_pmd_unshare, i_mmap_rwsem must be + * held in write mode. Caller needs to explicitly + * do this outside rmap routines. + */ + VM_BUG_ON(!anon && !(flags & TTU_RMAP_LOCKED)); + if (!anon && huge_pmd_unshare(mm, vma, &address, pvmw.pte)) { + flush_tlb_range(vma, range.start, range.end); + mmu_notifier_invalidate_range(mm, range.start, + range.end); + /* - * To call huge_pmd_unshare, i_mmap_rwsem must be - * held in write mode. Caller needs to explicitly - * do this outside rmap routines. + * The ref count of the PMD page was dropped + * which is part of the way map counting + * is done for shared PMDs. Return 'true' + * here. When there is no other sharing, + * huge_pmd_unshare returns false and we will + * unmap the actual page and drop map count + * to zero. */ - VM_BUG_ON(!(flags & TTU_RMAP_LOCKED)); - - if (huge_pmd_unshare(mm, vma, &address, pvmw.pte)) { - flush_tlb_range(vma, range.start, range.end); - mmu_notifier_invalidate_range(mm, range.start, - range.end); - - /* - * The ref count of the PMD page was dropped - * which is part of the way map counting - * is done for shared PMDs. Return 'true' - * here. When there is no other sharing, - * huge_pmd_unshare returns false and we will - * unmap the actual page and drop map count - * to zero. - */ - page_vma_mapped_walk_done(&pvmw); - break; - } + page_vma_mapped_walk_done(&pvmw); + break; } /* Nuke the hugetlb page table entry */ _ Patches currently in -mm which might be from baolin.wang@linux.alibaba.com are mm-hugetlb-remove-unnecessary-huge_ptep_set_access_flags-in-hugetlb_mcopy_atomic_pte.patch mm-rmap-simplify-the-hugetlb-handling-when-unmapping-or-migration.patch