From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 BE46921A44C for ; Fri, 27 Jun 2025 20:16:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751055406; cv=none; b=DF/XdVCqmkSdGW30FF7hKu05lE31uvDMnugAxMBxflkFO55oMfDtRRKnbIf8hKxkAOcvjg+rQhaTXF+mTznE5JjroKfHarcRjEFrAg8qwP7iqjrad2c2vPxaLc+g9tW2r7Pi5iSVi5U8cVO9oY1yL8duVW8hZ8Pb6Db6Ev6HjaQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751055406; c=relaxed/simple; bh=RXoicbsQAXbzM53H15AwtLwmEG4hAC1y39TtzX0C1aQ=; h=Date:To:From:Subject:Message-Id; b=D+ctV/9PaOqHXx3lb6+t9i1nBUNyuNwYySOUDgZWbEyZ8rRDx0/yPBMhQ0lgN3GCWTuimPQk8ZTTgr5VIGC7aPEcY52pHJ01cB7MGHcXwBoCDCSMsY4VdBwpDSJe1QIHnFwBITtXH7B9zsZdxwvfYawDnPLuJN04nu/1XhmKzkc= 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=rxNX9kfy; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="rxNX9kfy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 49D3AC4CEE3; Fri, 27 Jun 2025 20:16:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1751055405; bh=RXoicbsQAXbzM53H15AwtLwmEG4hAC1y39TtzX0C1aQ=; h=Date:To:From:Subject:From; b=rxNX9kfyz/oFJIzVcc7T6RJ4jbH6zuw36u5z5Xnu+tMFhZjMLYqy+EdvT5AL6P0eK jg3NMJ0iXi577xigvE9sWJUIobHPnFSBQ0okiBHpCn0SCwdDxrQ3gpbR8b9o1KjERl rBqN+yLeMK0kDeXUF8vdAxgUNE67fTOrqCZ7zJbY= Date: Fri, 27 Jun 2025 13:16:44 -0700 To: mm-commits@vger.kernel.org,willy@infradead.org,shikemeng@huaweicloud.com,nphamcs@gmail.com,hughd@google.com,dev.jain@arm.com,chrisl@kernel.org,bhe@redhat.com,baolin.wang@linux.alibaba.com,baohua@kernel.org,kasong@tencent.com,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-shmem-swap-tidy-up-thp-swapin-checks.patch added to mm-new branch Message-Id: <20250627201645.49D3AC4CEE3@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm/shmem, swap: tidy up THP swapin checks has been added to the -mm mm-new branch. Its filename is mm-shmem-swap-tidy-up-thp-swapin-checks.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-shmem-swap-tidy-up-thp-swapin-checks.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. 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: Kairui Song Subject: mm/shmem, swap: tidy up THP swapin checks Date: Fri, 27 Jun 2025 14:20:16 +0800 Move all THP swapin related checks under CONFIG_TRANSPARENT_HUGEPAGE, so they will be trimmed off by the compiler if not needed. And add a WARN if shmem sees a order > 0 entry when CONFIG_TRANSPARENT_HUGEPAGE is disabled, that should never happen unless things went very wrong. There should be no observable feature change except the new added WARN. Link: https://lkml.kernel.org/r/20250627062020.534-4-ryncsn@gmail.com Signed-off-by: Kairui Song Cc: Baolin Wang Cc: Baoquan He Cc: Barry Song Cc: Chris Li Cc: Dev Jain Cc: Hugh Dickins Cc: Kemeng Shi Cc: Matthew Wilcox (Oracle) Cc: Nhat Pham Signed-off-by: Andrew Morton --- mm/shmem.c | 42 ++++++++++++++++++++---------------------- 1 file changed, 20 insertions(+), 22 deletions(-) --- a/mm/shmem.c~mm-shmem-swap-tidy-up-thp-swapin-checks +++ a/mm/shmem.c @@ -1980,26 +1980,39 @@ static struct folio *shmem_swap_alloc_fo swp_entry_t entry, int order, gfp_t gfp) { struct shmem_inode_info *info = SHMEM_I(inode); + int nr_pages = 1 << order; struct folio *new; void *shadow; - int nr_pages; /* * We have arrived here because our zones are constrained, so don't * limit chance of success with further cpuset and node constraints. */ gfp &= ~GFP_CONSTRAINT_MASK; - if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && order > 0) { - gfp_t huge_gfp = vma_thp_gfp_mask(vma); - - gfp = limit_gfp_mask(huge_gfp, gfp); + if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) { + if (WARN_ON_ONCE(order)) + return ERR_PTR(-EINVAL); + } else if (order) { + /* + * If uffd is active for the vma, we need per-page fault + * fidelity to maintain the uffd semantics, then fallback + * to swapin order-0 folio, as well as for zswap case. + * Any existing sub folio in the swap cache also blocks + * mTHP swapin. + */ + if ((vma && unlikely(userfaultfd_armed(vma))) || + !zswap_never_enabled() || + non_swapcache_batch(entry, nr_pages) != nr_pages) { + return ERR_PTR(-EINVAL); + } else { + gfp = limit_gfp_mask(vma_thp_gfp_mask(vma), gfp); + } } new = shmem_alloc_folio(gfp, order, info, index); if (!new) return ERR_PTR(-ENOMEM); - nr_pages = folio_nr_pages(new); if (mem_cgroup_swapin_charge_folio(new, vma ? vma->vm_mm : NULL, gfp, entry)) { folio_put(new); @@ -2283,9 +2296,6 @@ static int shmem_swapin_folio(struct ino /* Look it up and read it in.. */ folio = swap_cache_get_folio(swap, NULL, 0); if (!folio) { - int nr_pages = 1 << order; - bool fallback_order0 = false; - /* Or update major stats only when swapin succeeds?? */ if (fault_type) { *fault_type |= VM_FAULT_MAJOR; @@ -2293,20 +2303,8 @@ static int shmem_swapin_folio(struct ino count_memcg_event_mm(fault_mm, PGMAJFAULT); } - /* - * If uffd is active for the vma, we need per-page fault - * fidelity to maintain the uffd semantics, then fallback - * to swapin order-0 folio, as well as for zswap case. - * Any existing sub folio in the swap cache also blocks - * mTHP swapin. - */ - if (order > 0 && ((vma && unlikely(userfaultfd_armed(vma))) || - !zswap_never_enabled() || - non_swapcache_batch(swap, nr_pages) != nr_pages)) - fallback_order0 = true; - /* Skip swapcache for synchronous device. */ - if (!fallback_order0 && data_race(si->flags & SWP_SYNCHRONOUS_IO)) { + if (data_race(si->flags & SWP_SYNCHRONOUS_IO)) { folio = shmem_swap_alloc_folio(inode, vma, index, swap, order, gfp); if (!IS_ERR(folio)) { skip_swapcache = true; _ Patches currently in -mm which might be from kasong@tencent.com are mm-list_lru-refactor-the-locking-code.patch mm-shmem-swap-improve-cached-mthp-handling-and-fix-potential-hung.patch mm-shmem-swap-avoid-redundant-xarray-lookup-during-swapin.patch mm-shmem-swap-tidy-up-thp-swapin-checks.patch mm-shmem-swap-clean-up-swap-entry-splitting.patch mm-shmem-swap-never-use-swap-cache-and-readahead-for-swp_synchronous_io.patch mm-shmem-swap-fix-major-fault-counting.patch mm-shmem-swap-avoid-false-positive-swap-cache-lookup.patch