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 35986CDB474 for ; Fri, 20 Oct 2023 17:26:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229954AbjJTR04 (ORCPT ); Fri, 20 Oct 2023 13:26:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57476 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1377706AbjJTR0u (ORCPT ); Fri, 20 Oct 2023 13:26:50 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9EB8DD72 for ; Fri, 20 Oct 2023 10:26:44 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3AC6FC433C8; Fri, 20 Oct 2023 17:26:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1697822804; bh=s9s1Ozmn3daGeGpUMO2VWWWzPNqsWew/KBXYxLLA0Xs=; h=Date:To:From:Subject:From; b=lfrMUmr6TF3CUsSQZgLYf1dkwoSVT+WEMVC99x7g48/FTbZ+rUJzq1PJNZ9X6/3TT DzLXpDkcE4CS2i/uoFy0t34WrFDh5qMjxFr37s4PrRPWsxWdqEV2KlsLhiSQbvuPvu 8fQfcuozWiO5cSf8r6fNxGhPCgV0gD7q2I2/VHuI= Date: Fri, 20 Oct 2023 10:26:43 -0700 To: mm-commits@vger.kernel.org, yosryahmed@google.com, ying.huang@intel.com, willy@infradead.org, wangkefeng.wang@huawei.com, vishal.moola@gmail.com, tj@kernel.org, surenb@google.com, sidhartha.kumar@oracle.com, shy828301@gmail.com, nphamcs@gmail.com, mike.kravetz@oracle.com, mhocko@suse.com, mgorman@techsingularity.net, gregkh@linuxfoundation.org, david@redhat.com, cl@linux.com, ak@linux.intel.com, hughd@google.com, akpm@linux-foundation.org From: Andrew Morton Subject: + mempolicy-remove-confusing-mpol_mf_lazy-dead-code.patch added to mm-unstable branch Message-Id: <20231020172644.3AC6FC433C8@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: mempolicy: remove confusing MPOL_MF_LAZY dead code has been added to the -mm mm-unstable branch. Its filename is mempolicy-remove-confusing-mpol_mf_lazy-dead-code.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mempolicy-remove-confusing-mpol_mf_lazy-dead-code.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: Hugh Dickins Subject: mempolicy: remove confusing MPOL_MF_LAZY dead code Date: Tue, 3 Oct 2023 02:24:18 -0700 (PDT) v3.8 commit b24f53a0bea3 ("mm: mempolicy: Add MPOL_MF_LAZY") introduced MPOL_MF_LAZY, and included it in the MPOL_MF_VALID flags; but a720094ded8 ("mm: mempolicy: Hide MPOL_NOOP and MPOL_MF_LAZY from userspace for now") immediately removed it from MPOL_MF_VALID flags, pending further review. "This will need to be revisited", but it has not been reinstated. The present state is confusing: there is dead code in mm/mempolicy.c to handle MPOL_MF_LAZY cases which can never occur. Remove that: it can be resurrected later if necessary. But keep the definition of MPOL_MF_LAZY, which must remain in the UAPI, even though it always fails with EINVAL. https://lore.kernel.org/linux-mm/1553041659-46787-1-git-send-email-yang.shi@linux.alibaba.com/ links to a previous request to remove MPOL_MF_LAZY. Link: https://lkml.kernel.org/r/80c9665c-1c3f-17ba-21a3-f6115cebf7d@google.com Signed-off-by: Hugh Dickins Reviewed-by: Matthew Wilcox (Oracle) Reviewed-by: Yang Shi Cc: Andi Kleen Cc: Christoph Lameter Cc: David Hildenbrand Cc: Greg Kroah-Hartman Cc: "Huang, Ying" Cc: Kefeng Wang Cc: Mel Gorman Cc: Michal Hocko Cc: Mike Kravetz Cc: Nhat Pham Cc: Sidhartha Kumar Cc: Suren Baghdasaryan Cc: Tejun heo Cc: Vishal Moola (Oracle) Cc: Yosry Ahmed Signed-off-by: Andrew Morton --- include/uapi/linux/mempolicy.h | 2 +- mm/mempolicy.c | 18 ------------------ 2 files changed, 1 insertion(+), 19 deletions(-) --- a/include/uapi/linux/mempolicy.h~mempolicy-remove-confusing-mpol_mf_lazy-dead-code +++ a/include/uapi/linux/mempolicy.h @@ -48,7 +48,7 @@ enum { #define MPOL_MF_MOVE (1<<1) /* Move pages owned by this process to conform to policy */ #define MPOL_MF_MOVE_ALL (1<<2) /* Move every page to conform to policy */ -#define MPOL_MF_LAZY (1<<3) /* Modifies '_MOVE: lazy migrate on fault */ +#define MPOL_MF_LAZY (1<<3) /* UNSUPPORTED FLAG: Lazy migrate on fault */ #define MPOL_MF_INTERNAL (1<<4) /* Internal flags start here */ #define MPOL_MF_VALID (MPOL_MF_STRICT | \ --- a/mm/mempolicy.c~mempolicy-remove-confusing-mpol_mf_lazy-dead-code +++ a/mm/mempolicy.c @@ -636,12 +636,6 @@ unsigned long change_prot_numa(struct vm return nr_updated; } -#else -static unsigned long change_prot_numa(struct vm_area_struct *vma, - unsigned long addr, unsigned long end) -{ - return 0; -} #endif /* CONFIG_NUMA_BALANCING */ static int queue_pages_test_walk(unsigned long start, unsigned long end, @@ -680,14 +674,6 @@ static int queue_pages_test_walk(unsigne if (endvma > end) endvma = end; - if (flags & MPOL_MF_LAZY) { - /* Similar to task_numa_work, skip inaccessible VMAs */ - if (!is_vm_hugetlb_page(vma) && vma_is_accessible(vma) && - !(vma->vm_flags & VM_MIXEDMAP)) - change_prot_numa(vma, start, endvma); - return 1; - } - /* * Check page nodes, and queue pages to move, in the current vma. * But if no moving, and no strict checking, the scan can be skipped. @@ -1254,9 +1240,6 @@ static long do_mbind(unsigned long start if (IS_ERR(new)) return PTR_ERR(new); - if (flags & MPOL_MF_LAZY) - new->flags |= MPOL_F_MOF; - /* * If we are using the default policy then operation * on discontinuous address spaces is okay after all @@ -1301,7 +1284,6 @@ static long do_mbind(unsigned long start if (!err) { if (!list_empty(&pagelist)) { - WARN_ON_ONCE(flags & MPOL_MF_LAZY); nr_failed |= migrate_pages(&pagelist, new_folio, NULL, start, MIGRATE_SYNC, MR_MEMPOLICY_MBIND, NULL); } _ Patches currently in -mm which might be from hughd@google.com are hugetlbfs-drop-shared-numa-mempolicy-pretence.patch kernfs-drop-shared-numa-mempolicy-hooks.patch mempolicy-fix-migrate_pages2-syscall-return-nr_failed.patch mempolicy-trivia-delete-those-ancient-pr_debugs.patch mempolicy-trivia-slightly-more-consistent-naming.patch mempolicy-trivia-use-pgoff_t-in-shared-mempolicy-tree.patch mempolicy-mpol_shared_policy_init-without-pseudo-vma.patch mempolicy-remove-confusing-mpol_mf_lazy-dead-code.patch mm-add-page_rmappable_folio-wrapper.patch mempolicy-alloc_pages_mpol-for-numa-policy-without-vma.patch mempolicy-mmap_lock-is-not-needed-while-migrating-folios.patch mempolicy-migration-attempt-to-match-interleave-nodes.patch