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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 80A17C433F5 for ; Mon, 2 May 2022 18:17:30 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 17C986B0073; Mon, 2 May 2022 14:17:30 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1048A6B0074; Mon, 2 May 2022 14:17:30 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E4AF56B0075; Mon, 2 May 2022 14:17:29 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.a.hostedemail.com [64.99.140.24]) by kanga.kvack.org (Postfix) with ESMTP id D0E706B0073 for ; Mon, 2 May 2022 14:17:29 -0400 (EDT) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 9C65D2A722 for ; Mon, 2 May 2022 18:17:29 +0000 (UTC) X-FDA: 79421610618.05.61226C7 Received: from mail-pf1-f202.google.com (mail-pf1-f202.google.com [209.85.210.202]) by imf24.hostedemail.com (Postfix) with ESMTP id EE65B180099 for ; Mon, 2 May 2022 18:17:23 +0000 (UTC) Received: by mail-pf1-f202.google.com with SMTP id x16-20020aa793b0000000b0050d3d5c4f4eso8395097pff.6 for ; Mon, 02 May 2022 11:17:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=feb3hdgUhXYlLWlaSi+Zt7sm/tCIhpJou4kzEHLcVAI=; b=hgEnS/aHUQsEncWhEF3eT6L8okSLHnQk4O1WQbAlnF7OshsG9ltjoTkTIgL5o7Q/mC kapHbxcdrvQGyxVBx86Y3bKgpMi1sZz5pkgEhPQMIiwY2TY/BIEjJM9Sl0nFICH10XIw goW6AtWFFYzNqFHk+fm7NihZqp8KzJaQbGItM2Msp2VGlG3/v5xfzOZeIPYKg9BQhUr0 +dklnNu5dS61857SPkeTw2KM701iK1ZPFhgqW57YwhrObRDvydj/+5telry70mhgbhgf xgyNoR+3AjyOQ5kLZZ0bHfftY0XfT3+IlSNT3xinOQ1mz7ysY0XRKkBSKrjDm0Dxnq1d NoQQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=feb3hdgUhXYlLWlaSi+Zt7sm/tCIhpJou4kzEHLcVAI=; b=74Zw0vL4aPtSRfKxAywGZRDzdo5QWoyIFpH3bks+SuZcH5kS6au1uCu5aSTjWQ4UYI dSCv+XWtqd6ONrfcYRE/jJALB/I3/Rh1Uy6KsiGy50OCA4F2lMbSNsAFdM7nQsSZG8PL o571cQ3+o6Jae51LqEeMPMxD3oUbHH15CagvvMkUjFFlndMavf5/waZX8PoahrvZHy9X UahlP6c31YcnIC2N5jL8zw9Q7hgGb+EaLloS9b0NDleDiC18FlMYdipzhKzaPL6MNWhM 2rdKacMinK3CpZ5hy9QWFYyCLyz06DqExteaf7/Bm9xqnBf1DFqgCse/80KGij+wWHfL /tKA== X-Gm-Message-State: AOAM533fU9j19/4cqrR2TMVPbpsE1GyL0K82RzJV5y3/rZyV5nFFtRuh BjzxJnsEWqXyPHFN88NDs1UaMmlbyVSA X-Google-Smtp-Source: ABdhPJxeuEFT8nyEOb+n5S5K0ziCrDPYexiA2edznGGjSf8eX+3X622yGMYKvf39CP+4Eo9Ib6wmZST/qDJg X-Received: from zokeefe3.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:1b6]) (user=zokeefe job=sendgmr) by 2002:a17:90b:3b4c:b0:1da:2001:a222 with SMTP id ot12-20020a17090b3b4c00b001da2001a222mr469243pjb.84.1651515448148; Mon, 02 May 2022 11:17:28 -0700 (PDT) Date: Mon, 2 May 2022 11:17:02 -0700 In-Reply-To: <20220502181714.3483177-1-zokeefe@google.com> Message-Id: <20220502181714.3483177-2-zokeefe@google.com> Mime-Version: 1.0 References: <20220502181714.3483177-1-zokeefe@google.com> X-Mailer: git-send-email 2.36.0.464.gb9c8b46e94-goog Subject: [PATCH v4 01/13] mm/khugepaged: record SCAN_PMD_MAPPED when scan_pmd() finds THP From: "Zach O'Keefe" To: Alex Shi , David Hildenbrand , David Rientjes , Matthew Wilcox , Michal Hocko , Pasha Tatashin , Peter Xu , SeongJae Park , Song Liu , Vlastimil Babka , Yang Shi , Zi Yan , linux-mm@kvack.org Cc: Andrea Arcangeli , Andrew Morton , Arnd Bergmann , Axel Rasmussen , Chris Kennelly , Chris Zankel , Helge Deller , Hugh Dickins , Ivan Kokshaysky , "James E.J. Bottomley" , Jens Axboe , "Kirill A. Shutemov" , Matt Turner , Max Filippov , Miaohe Lin , Minchan Kim , Patrick Xia , Pavel Begunkov , Thomas Bogendoerfer , "Zach O'Keefe" Content-Type: text/plain; charset="UTF-8" X-Stat-Signature: kzwybyhhooz5go94enin3tk456b79hba Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b="hgEnS/aH"; spf=pass (imf24.hostedemail.com: domain of 3OCBwYgcKCFMK95zz0z19916z.x97638FI-775Gvx5.9C1@flex--zokeefe.bounces.google.com designates 209.85.210.202 as permitted sender) smtp.mailfrom=3OCBwYgcKCFMK95zz0z19916z.x97638FI-775Gvx5.9C1@flex--zokeefe.bounces.google.com; dmarc=pass (policy=reject) header.from=google.com X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: EE65B180099 X-HE-Tag: 1651515443-313868 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: When scanning an anon pmd to see if it's eligible for collapse, return SCAN_PMD_MAPPED if the pmd already maps a THP. Note that SCAN_PMD_MAPPED is different from SCAN_PAGE_COMPOUND used in the file-collapse path, since the latter might identify pte-mapped compound pages. This is required by MADV_COLLAPSE which necessarily needs to know what hugepage-aligned/sized regions are already pmd-mapped. Signed-off-by: Zach O'Keefe --- include/trace/events/huge_memory.h | 1 + mm/internal.h | 1 + mm/khugepaged.c | 30 ++++++++++++++++++++++++++---- mm/rmap.c | 15 +++++++++++++-- 4 files changed, 41 insertions(+), 6 deletions(-) diff --git a/include/trace/events/huge_memory.h b/include/trace/events/huge_memory.h index d651f3437367..55392bf30a03 100644 --- a/include/trace/events/huge_memory.h +++ b/include/trace/events/huge_memory.h @@ -11,6 +11,7 @@ EM( SCAN_FAIL, "failed") \ EM( SCAN_SUCCEED, "succeeded") \ EM( SCAN_PMD_NULL, "pmd_null") \ + EM( SCAN_PMD_MAPPED, "page_pmd_mapped") \ EM( SCAN_EXCEED_NONE_PTE, "exceed_none_pte") \ EM( SCAN_EXCEED_SWAP_PTE, "exceed_swap_pte") \ EM( SCAN_EXCEED_SHARED_PTE, "exceed_shared_pte") \ diff --git a/mm/internal.h b/mm/internal.h index 0667abd57634..51ae9f71a2a3 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -172,6 +172,7 @@ extern void reclaim_throttle(pg_data_t *pgdat, enum vmscan_throttle_state reason /* * in mm/rmap.c: */ +pmd_t *mm_find_pmd_raw(struct mm_struct *mm, unsigned long address); extern pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address); /* diff --git a/mm/khugepaged.c b/mm/khugepaged.c index eb444fd45568..2c2ed6b4d96c 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -28,6 +28,7 @@ enum scan_result { SCAN_FAIL, SCAN_SUCCEED, SCAN_PMD_NULL, + SCAN_PMD_MAPPED, SCAN_EXCEED_NONE_PTE, SCAN_EXCEED_SWAP_PTE, SCAN_EXCEED_SHARED_PTE, @@ -977,6 +978,29 @@ static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address, return 0; } +static int find_pmd_or_thp_or_none(struct mm_struct *mm, + unsigned long address, + pmd_t **pmd) +{ + pmd_t pmde; + + *pmd = mm_find_pmd_raw(mm, address); + if (!*pmd) + return SCAN_PMD_NULL; + + pmde = pmd_read_atomic(*pmd); + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + /* See comments in pmd_none_or_trans_huge_or_clear_bad() */ + barrier(); +#endif + if (!pmd_present(pmde)) + return SCAN_PMD_NULL; + if (pmd_trans_huge(pmde)) + return SCAN_PMD_MAPPED; + return SCAN_SUCCEED; +} + /* * Bring missing pages in from swap, to complete THP collapse. * Only done if khugepaged_scan_pmd believes it is worthwhile. @@ -1228,11 +1252,9 @@ static int khugepaged_scan_pmd(struct mm_struct *mm, VM_BUG_ON(address & ~HPAGE_PMD_MASK); - pmd = mm_find_pmd(mm, address); - if (!pmd) { - result = SCAN_PMD_NULL; + result = find_pmd_or_thp_or_none(mm, address, &pmd); + if (result != SCAN_SUCCEED) goto out; - } memset(khugepaged_node_load, 0, sizeof(khugepaged_node_load)); pte = pte_offset_map_lock(mm, pmd, address, &ptl); diff --git a/mm/rmap.c b/mm/rmap.c index 94d6b24a1ac2..6980b4011bf8 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -759,13 +759,12 @@ unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma) return vma_address(page, vma); } -pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address) +pmd_t *mm_find_pmd_raw(struct mm_struct *mm, unsigned long address) { pgd_t *pgd; p4d_t *p4d; pud_t *pud; pmd_t *pmd = NULL; - pmd_t pmde; pgd = pgd_offset(mm, address); if (!pgd_present(*pgd)) @@ -780,6 +779,18 @@ pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address) goto out; pmd = pmd_offset(pud, address); +out: + return pmd; +} + +pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address) +{ + pmd_t pmde; + pmd_t *pmd; + + pmd = mm_find_pmd_raw(mm, address); + if (!pmd) + goto out; /* * Some THP functions use the sequence pmdp_huge_clear_flush(), set_pmd_at() * without holding anon_vma lock for write. So when looking for a -- 2.36.0.464.gb9c8b46e94-goog