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 9C4E0C43334 for ; Mon, 4 Jul 2022 01:13:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232837AbiGDBNF (ORCPT ); Sun, 3 Jul 2022 21:13:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39730 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232565AbiGDBL6 (ORCPT ); Sun, 3 Jul 2022 21:11:58 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D632A6434 for ; Sun, 3 Jul 2022 18:11:00 -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 ams.source.kernel.org (Postfix) with ESMTPS id 80A06B80C73 for ; Mon, 4 Jul 2022 01:10:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 200D8C341C7; Mon, 4 Jul 2022 01:10:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1656897058; bh=xXFG3iwoLxeMlerUrDzK3PltcORdD1UkHl5T8iEB4DY=; h=Date:To:From:Subject:From; b=USR/6GbQ+4cY6XD6AJ8wRV5zGtu8kpbdwWguRm5//P1ZMlBHIaikZZeLr1MknfXCX 6WG3LhI5+IuM/ZS9x/vDoGOibAjegZHp/tlNviUhc33Z8VqOJSF0SGAzRis5LYDhyF GchEGFmqQ4duOiazpnB6kMlZAFvS1iNXmBJPRAcA= Date: Sun, 03 Jul 2022 18:10:57 -0700 To: mm-commits@vger.kernel.org, zokeefe@google.com, willy@infradead.org, vbabka@suse.cz, surenb@google.com, shy828301@gmail.com, peterx@redhat.com, neilb@suse.de, dhowells@redhat.com, david@redhat.com, apopple@nvidia.com, aarcange@redhat.com, linmiaohe@huawei.com, akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] mm-khugepaged-stop-swapping-in-page-when-vm_fault_retry-occurs.patch removed from -mm tree Message-Id: <20220704011058.200D8C341C7@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The quilt patch titled Subject: mm/khugepaged: stop swapping in page when VM_FAULT_RETRY occurs has been removed from the -mm tree. Its filename was mm-khugepaged-stop-swapping-in-page-when-vm_fault_retry-occurs.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Miaohe Lin Subject: mm/khugepaged: stop swapping in page when VM_FAULT_RETRY occurs Date: Sat, 25 Jun 2022 17:28:11 +0800 When do_swap_page returns VM_FAULT_RETRY, we do not retry here and thus swap entry will remain in pagetable. This will result in later failure. So stop swapping in pages in this case to save cpu cycles. As A further optimization, mmap_lock is released when __collapse_huge_page_swapin() fails to avoid relocking mmap_lock. And "swapped_in++" is moved after error handling to make it more accurate. Link: https://lkml.kernel.org/r/20220625092816.4856-3-linmiaohe@huawei.com Signed-off-by: Miaohe Lin Cc: Alistair Popple Cc: Andrea Arcangeli Cc: David Hildenbrand Cc: David Howells Cc: Matthew Wilcox (Oracle) Cc: NeilBrown Cc: Peter Xu Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Yang Shi Cc: Zach O'Keefe Signed-off-by: Andrew Morton --- mm/khugepaged.c | 32 ++++++++++++++------------------ 1 file changed, 14 insertions(+), 18 deletions(-) --- a/mm/khugepaged.c~mm-khugepaged-stop-swapping-in-page-when-vm_fault_retry-occurs +++ a/mm/khugepaged.c @@ -972,8 +972,8 @@ static int hugepage_vma_revalidate(struc * Bring missing pages in from swap, to complete THP collapse. * Only done if khugepaged_scan_pmd believes it is worthwhile. * - * Called and returns without pte mapped or spinlocks held, - * but with mmap_lock held to protect against vma changes. + * Called and returns without pte mapped or spinlocks held. + * Note that if false is returned, mmap_lock will be released. */ static bool __collapse_huge_page_swapin(struct mm_struct *mm, @@ -1000,27 +1000,24 @@ static bool __collapse_huge_page_swapin( pte_unmap(vmf.pte); continue; } - swapped_in++; ret = do_swap_page(&vmf); - /* do_swap_page returns VM_FAULT_RETRY with released mmap_lock */ + /* + * do_swap_page returns VM_FAULT_RETRY with released mmap_lock. + * Note we treat VM_FAULT_RETRY as VM_FAULT_ERROR here because + * we do not retry here and swap entry will remain in pagetable + * resulting in later failure. + */ if (ret & VM_FAULT_RETRY) { - mmap_read_lock(mm); - if (hugepage_vma_revalidate(mm, haddr, &vma)) { - /* vma is no longer available, don't continue to swapin */ - trace_mm_collapse_huge_page_swapin(mm, swapped_in, referenced, 0); - return false; - } - /* check if the pmd is still valid */ - if (mm_find_pmd(mm, haddr) != pmd) { - trace_mm_collapse_huge_page_swapin(mm, swapped_in, referenced, 0); - return false; - } + trace_mm_collapse_huge_page_swapin(mm, swapped_in, referenced, 0); + return false; } if (ret & VM_FAULT_ERROR) { + mmap_read_unlock(mm); trace_mm_collapse_huge_page_swapin(mm, swapped_in, referenced, 0); return false; } + swapped_in++; } /* Drain LRU add pagevec to remove extra pin on the swapped in pages */ @@ -1086,13 +1083,12 @@ static void collapse_huge_page(struct mm } /* - * __collapse_huge_page_swapin always returns with mmap_lock locked. - * If it fails, we release mmap_lock and jump out_nolock. + * __collapse_huge_page_swapin will return with mmap_lock released + * when it fails. So we jump out_nolock directly in that case. * Continuing to collapse causes inconsistency. */ if (unmapped && !__collapse_huge_page_swapin(mm, vma, address, pmd, referenced)) { - mmap_read_unlock(mm); goto out_nolock; } _ Patches currently in -mm which might be from linmiaohe@huawei.com are mm-khugepaged-trivial-typo-and-codestyle-cleanup.patch mm-khugepaged-minor-cleanup-for-collapse_file.patch mm-khugepaged-use-helper-macro-__attr_rw.patch mm-khugepaged-remove-unneeded-return-value-of-khugepaged_add_pte_mapped_thp.patch mm-khugepaged-try-to-free-transhuge-swapcache-when-possible.patch mm-page_alloc-minor-clean-up-for-memmap_init_compound.patch mm-mmapc-fix-missing-call-to-vm_unacct_memory-in-mmap_region.patch filemap-minor-cleanup-for-filemap_write_and_wait_range.patch