From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3EFCF4825D4 for ; Tue, 13 Oct 2026 04:33:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791866027; cv=none; b=UlwGDjbyMUJlnvIB8CJccONGJE0i3KM/HSZNWxnUlahvn60SLaCDte99T6qd0W/Gp5O4hFSR3VH1uuvOC3xZgqjkF0gnRuyGNDdn3ARYqZ7cdhjy0TfrwcCIX7TMRWnJBXmvcTSZb5C4u+tphwUjNanMMZ3mMX3YYAbjVtJe2tg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791866027; c=relaxed/simple; bh=Tfl/y6GzZAhofqHZbQ9x+Pb1X1X8gd6fwibPHTocxaE=; h=Date:To:From:Subject:Message-Id; b=hocNuRwdiM0QCjzqbq0M3myUytvOdqyjIlFEH6IILEPesgvrWWtbxJtX6l1e9qJMR0YAyaGrp9jCi5tCLZ2iZQXtaxyxhLwDR+GCXupSXzLK2ailoa82PbVig0cpk5AwDrb5GruHnE6Tqp7SE/Xlff0OKIh7FSL40keJ1CJHVCM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=lFMmTK2W; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="lFMmTK2W" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ACC711F00899; Tue, 13 Oct 2026 04:33:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1791866020; bh=o9E/NqWcQt83jKZFI/ttAnpVHCd4PwfSxgocp25bT1Y=; h=Date:To:From:Subject; b=lFMmTK2Wgbhugpi/CMr1AvqgfR0DYx/M9fgvLnR4iY+87eB4nOi6QapyIaQJNdMdi DkklZl5S/l24xCwad6jhWslm19XZUYfXQAhbYvqTMquu/XgydTldbKbwA4t9xshUCv KHCzz/4IEMf+8mpDG4SyrlSF3neDmllixSe+Pcu0= Date: Mon, 12 Oct 2026 21:33:40 -0700 To: mm-commits@vger.kernel.org,ziy@nvidia.com,vbabka@kernel.org,usama.arif@linux.dev,usama.anjum@arm.com,surenb@google.com,shuah@kernel.org,ryan.roberts@arm.com,rppt@kernel.org,nico.pache@linux.dev,mhocko@suse.com,ljs@kernel.org,liam@infradead.org,leon@kernel.org,lance.yang@linux.dev,kernel-team@meta.com,jgg@ziepe.ca,hughd@google.com,dev.jain@arm.com,david@kernel.org,baolin.wang@linux.alibaba.com,baohua@kernel.org,agordeev@linux.ibm.com,kas@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] selftests-mm-make-the-swap-cases-swapout-reliable.patch removed from -mm tree Message-Id: <20261013043340.ACC711F00899@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: selftests/mm: make the swap cases' swapout reliable has been removed from the -mm tree. Its filename was selftests-mm-make-the-swap-cases-swapout-reliable.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: "Kiryl Shutsemau (Meta)" Subject: selftests/mm: make the swap cases' swapout reliable Date: Sat, 19 Sep 2026 01:24:35 +0100 collapse_swapin_single_pte() and collapse_max_ptes_swap() swap a range out and then require smaps to report exactly the count they asked for. Two things keep that count from arriving. MADV_PAGEOUT is best effort, so the count often turns up a moment late. And wait_for_scan() leaves the range eligible for collapsing, so khugepaged is still working on it. Collapsing reads the swapped-out pages back in, so the daemon empties the swap as fast as the case fills it. On arm64 with 64K pages max_ptes_swap is 1024 pages, which is 64M a step, and the case loses the race: # Swapout 1024 of 8192 pages... Fail not ok 10 collapse_max_ptes_swap Retry for up to two seconds, holding the range out of khugepaged's reach meanwhile. The collapse each case runs next restores MADV_HUGEPAGE, so only the setup is affected. If the pages still won't swap out, skip: no swap, swap too small or full, a memcg cap or busy writeback. None of that is a kernel bug. Link: https://lore.kernel.org/20260919002451.496763-6-kirill@shutemov.name Signed-off-by: Kiryl Shutsemau (Meta) Signed-off-by: Andrew Morton Reviewed-by: Muhammad Usama Anjum Reviewed-by: Baolin Wang Tested-by: Muhammad Usama Anjum Assisted-by: LLM Cc: Alexander Gordeev Cc: Barry Song Cc: "David Hildenbrand (arm)" Cc: Dev Jain Cc: Hugh Dickens Cc: Jason Gunthorpe Cc: kernel-team@meta.com Cc: Lance Yang Cc: Leon Romanovsky Cc: Liam Howlett Cc: Lorenzo Stoakes (ARM) Cc: Michal Hocko Cc: Mike Rapoport (Microsoft) Cc: Nico Pache (Red Hat) Cc: Ryan Roberts Cc: Shuah Khan (Samsung OSG) Cc: Suren Baghdasaryan Cc: Usama Arif Cc: "Vlastimil Babka (SUSE)" Cc: Zi Yan --- tools/testing/selftests/mm/khugepaged.c | 41 +++++++++++++++------- 1 file changed, 29 insertions(+), 12 deletions(-) --- a/tools/testing/selftests/mm/khugepaged.c~selftests-mm-make-the-swap-cases-swapout-reliable +++ a/tools/testing/selftests/mm/khugepaged.c @@ -221,6 +221,29 @@ err_out: return swap; } +static bool swapout_range(void *p, unsigned long size) +{ + int i; + + /* keep khugepaged from collapsing the range and swapping it back in */ + if (madvise(p, size, MADV_NOHUGEPAGE)) + ksft_exit_fail_perror("madvise(MADV_NOHUGEPAGE)"); + + /* + * Retry several times because MADV_PAGEOUT is best effort. Sleep + * between the retries to give outstanding writeback a chance to + * finish. + */ + for (i = 0; i < 40; i++) { + if (madvise(p, size, MADV_PAGEOUT)) + ksft_exit_fail_perror("madvise(MADV_PAGEOUT)"); + if (check_swap(p, size)) + return true; + usleep(50 * 1000); + } + return false; +} + static void *alloc_mapping(int nr) { void *p; @@ -828,12 +851,10 @@ static void collapse_swapin_single_pte(s ops->fault(p, 0, hpage_pmd_size); ksft_print_msg("Swapout one page..."); - if (madvise(p, page_size, MADV_PAGEOUT)) - ksft_exit_fail_perror("madvise(MADV_PAGEOUT)"); - if (check_swap(p, page_size)) { + if (swapout_range(p, page_size)) { success("OK"); } else { - fail("Fail"); + skip("Could not swap out"); goto out; } @@ -854,12 +875,10 @@ static void collapse_max_ptes_swap(struc ops->fault(p, 0, hpage_pmd_size); ksft_print_msg("Swapout %d of %d pages...", max_ptes_swap + 1, hpage_pmd_nr); - if (madvise(p, (max_ptes_swap + 1) * page_size, MADV_PAGEOUT)) - ksft_exit_fail_perror("madvise(MADV_PAGEOUT)"); - if (check_swap(p, (max_ptes_swap + 1) * page_size)) { + if (swapout_range(p, (max_ptes_swap + 1) * page_size)) { success("OK"); } else { - fail("Fail"); + skip("Could not swap out"); goto out; } @@ -871,12 +890,10 @@ static void collapse_max_ptes_swap(struc ops->fault(p, 0, hpage_pmd_size); ksft_print_msg("Swapout %d of %d pages...", max_ptes_swap, hpage_pmd_nr); - if (madvise(p, max_ptes_swap * page_size, MADV_PAGEOUT)) - ksft_exit_fail_perror("madvise(MADV_PAGEOUT)"); - if (check_swap(p, max_ptes_swap * page_size)) { + if (swapout_range(p, max_ptes_swap * page_size)) { success("OK"); } else { - fail("Fail"); + skip("Could not swap out"); goto out; } _ Patches currently in -mm which might be from kas@kernel.org are mm-page_alloc-make-defrag_mode-retries-follow-the-promoted-order.patch mm-khugepaged-drop-redundant-mm_struct-pin-in-madvise_collapse.patch mm-khugepaged-count-collapses-where-khugepaged-makes-them.patch mm-khugepaged-rename-mthp_present_ptes-bitmap-to-eligible_ptes.patch mm-collapse-add-collapseh-for-the-collapse-interface.patch mm-collapse-state-what-a-collapse-may-do-in-the-policy.patch mm-collapse-drop-the-collapse_possible-wrapper.patch mm-collapse-name-the-per-table-scan-reset-for-what-it-resets.patch mm-collapse-call-collapse_file-from-collapse_single_pmd.patch mm-collapse-separate-scanning-a-pte-table-from-collapsing-it.patch mm-collapse-open-code-collapse_single_pmd-in-its-two-callers.patch mm-collapse-work-out-the-orders-a-vma-allows-once-per-vma.patch mm-collapse-declare-the-collapse-interface-in-collapseh.patch mm-collapse-implement-madv_collapse-in-madvisec.patch