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 1488BC77B7A for ; Fri, 2 Jun 2023 20:55:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236275AbjFBUzO (ORCPT ); Fri, 2 Jun 2023 16:55:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33080 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236299AbjFBUzM (ORCPT ); Fri, 2 Jun 2023 16:55:12 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BE452E43; Fri, 2 Jun 2023 13:55:10 -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 4512261770; Fri, 2 Jun 2023 20:55:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9DFBDC433D2; Fri, 2 Jun 2023 20:55:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1685739309; bh=Nzq/BuOYIQNUUb6G2pp3sjalDbiX/ZSQYUQpzzkpMQw=; h=Date:To:From:Subject:From; b=BxA7A7ZOdEOHS3OUGvY8tlfd/niNIEZXEd0tU8fH0RC6LL+xrSfsrLvjjGSsMsSnO JMJxAj6MrlqnG97ikPs8DDhw2Rl2DKG4sFRG/0gFkP3P1pWGY7MhHkb7ncdduE3AG/ dBkMKLnd2MHZj0UzglTEHp3BWVV+T13zLRptpnt4= Date: Fri, 02 Jun 2023 13:55:08 -0700 To: mm-commits@vger.kernel.org, ziy@nvidia.com, yuzhao@google.com, willy@infradead.org, urezki@gmail.com, stable@vger.kernel.org, sj@kernel.org, rppt@kernel.org, lstoakes@gmail.com, kirill.shutemov@linux.intel.com, hch@lst.de, hch@infradead.org, ryan.roberts@arm.com, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-damon-ops-common-atomically-test-and-clear-young-on-ptes-and-pmds.patch added to mm-unstable branch Message-Id: <20230602205509.9DFBDC433D2@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/damon/ops-common: atomically test and clear young on ptes and pmds has been added to the -mm mm-unstable branch. Its filename is mm-damon-ops-common-atomically-test-and-clear-young-on-ptes-and-pmds.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-damon-ops-common-atomically-test-and-clear-young-on-ptes-and-pmds.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: Ryan Roberts Subject: mm/damon/ops-common: atomically test and clear young on ptes and pmds Date: Fri, 2 Jun 2023 10:29:47 +0100 It is racy to non-atomically read a pte, then clear the young bit, then write it back as this could discard dirty information. Further, it is bad practice to directly set a pte entry within a table. Instead clearing young must go through the arch-provided helper, ptep_test_and_clear_young() to ensure it is modified atomically and to give the arch code visibility and allow it to check (and potentially modify) the operation. Link: https://lkml.kernel.org/r/20230602092949.545577-3-ryan.roberts@arm.com Fixes: 3f49584b262c ("mm/damon: implement primitives for the virtual memory address spaces"). Signed-off-by: Ryan Roberts Reviewed-by: Zi Yan Reviewed-by: SeongJae Park Reviewed-by: Mike Rapoport (IBM) Cc: Christoph Hellwig Cc: Christoph Hellwig Cc: Kirill A. Shutemov Cc: Lorenzo Stoakes Cc: Matthew Wilcox (Oracle) Cc: Uladzislau Rezki (Sony) Cc: Yu Zhao Cc: Signed-off-by: Andrew Morton --- mm/damon/ops-common.c | 16 ++++++---------- mm/damon/ops-common.h | 4 ++-- mm/damon/paddr.c | 4 ++-- mm/damon/vaddr.c | 4 ++-- 4 files changed, 12 insertions(+), 16 deletions(-) --- a/mm/damon/ops-common.c~mm-damon-ops-common-atomically-test-and-clear-young-on-ptes-and-pmds +++ a/mm/damon/ops-common.c @@ -37,7 +37,7 @@ struct folio *damon_get_folio(unsigned l return folio; } -void damon_ptep_mkold(pte_t *pte, struct mm_struct *mm, unsigned long addr) +void damon_ptep_mkold(pte_t *pte, struct vm_area_struct *vma, unsigned long addr) { bool referenced = false; struct folio *folio = damon_get_folio(pte_pfn(*pte)); @@ -45,13 +45,11 @@ void damon_ptep_mkold(pte_t *pte, struct if (!folio) return; - if (pte_young(*pte)) { + if (ptep_test_and_clear_young(vma, addr, pte)) referenced = true; - *pte = pte_mkold(*pte); - } #ifdef CONFIG_MMU_NOTIFIER - if (mmu_notifier_clear_young(mm, addr, addr + PAGE_SIZE)) + if (mmu_notifier_clear_young(vma->vm_mm, addr, addr + PAGE_SIZE)) referenced = true; #endif /* CONFIG_MMU_NOTIFIER */ @@ -62,7 +60,7 @@ void damon_ptep_mkold(pte_t *pte, struct folio_put(folio); } -void damon_pmdp_mkold(pmd_t *pmd, struct mm_struct *mm, unsigned long addr) +void damon_pmdp_mkold(pmd_t *pmd, struct vm_area_struct *vma, unsigned long addr) { #ifdef CONFIG_TRANSPARENT_HUGEPAGE bool referenced = false; @@ -71,13 +69,11 @@ void damon_pmdp_mkold(pmd_t *pmd, struct if (!folio) return; - if (pmd_young(*pmd)) { + if (pmdp_test_and_clear_young(vma, addr, pmd)) referenced = true; - *pmd = pmd_mkold(*pmd); - } #ifdef CONFIG_MMU_NOTIFIER - if (mmu_notifier_clear_young(mm, addr, addr + HPAGE_PMD_SIZE)) + if (mmu_notifier_clear_young(vma->vm_mm, addr, addr + HPAGE_PMD_SIZE)) referenced = true; #endif /* CONFIG_MMU_NOTIFIER */ --- a/mm/damon/ops-common.h~mm-damon-ops-common-atomically-test-and-clear-young-on-ptes-and-pmds +++ a/mm/damon/ops-common.h @@ -9,8 +9,8 @@ struct folio *damon_get_folio(unsigned long pfn); -void damon_ptep_mkold(pte_t *pte, struct mm_struct *mm, unsigned long addr); -void damon_pmdp_mkold(pmd_t *pmd, struct mm_struct *mm, unsigned long addr); +void damon_ptep_mkold(pte_t *pte, struct vm_area_struct *vma, unsigned long addr); +void damon_pmdp_mkold(pmd_t *pmd, struct vm_area_struct *vma, unsigned long addr); int damon_cold_score(struct damon_ctx *c, struct damon_region *r, struct damos *s); --- a/mm/damon/paddr.c~mm-damon-ops-common-atomically-test-and-clear-young-on-ptes-and-pmds +++ a/mm/damon/paddr.c @@ -24,9 +24,9 @@ static bool __damon_pa_mkold(struct foli while (page_vma_mapped_walk(&pvmw)) { addr = pvmw.address; if (pvmw.pte) - damon_ptep_mkold(pvmw.pte, vma->vm_mm, addr); + damon_ptep_mkold(pvmw.pte, vma, addr); else - damon_pmdp_mkold(pvmw.pmd, vma->vm_mm, addr); + damon_pmdp_mkold(pvmw.pmd, vma, addr); } return true; } --- a/mm/damon/vaddr.c~mm-damon-ops-common-atomically-test-and-clear-young-on-ptes-and-pmds +++ a/mm/damon/vaddr.c @@ -311,7 +311,7 @@ static int damon_mkold_pmd_entry(pmd_t * } if (pmd_trans_huge(*pmd)) { - damon_pmdp_mkold(pmd, walk->mm, addr); + damon_pmdp_mkold(pmd, walk->vma, addr); spin_unlock(ptl); return 0; } @@ -323,7 +323,7 @@ static int damon_mkold_pmd_entry(pmd_t * pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); if (!pte_present(*pte)) goto out; - damon_ptep_mkold(pte, walk->mm, addr); + damon_ptep_mkold(pte, walk->vma, addr); out: pte_unmap_unlock(pte, ptl); return 0; _ Patches currently in -mm which might be from ryan.roberts@arm.com are mm-vmalloc-must-set-pte-via-arch-code.patch mm-damon-ops-common-atomically-test-and-clear-young-on-ptes-and-pmds.patch mm-damon-ops-common-refactor-to-use-ptepmdp_clear_young_notify.patch mm-fix-failure-to-unmap-pte-on-highmem-systems.patch