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 0918A22B8A9 for ; Fri, 4 Jul 2025 20:20:02 +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=1751660403; cv=none; b=Cbs2K0POXl3lss0SV0XwP+uCs6WP8lY7fOHAPMR6osDVdnwUmiIJZdule/FLh3bJYXkz7Fe8h1qutL7dwUeGjDuEn/iJkLfmwT2HssiQyGnRm69kzS0781bPy3azjEoUQomoSo2DQSRvSip8suGClesadzii91RR6zpBabhy9vI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751660403; c=relaxed/simple; bh=S3E1echE239FgnH8WWGAM6+Zc/ReCZ1qZhDc3/2Sp4M=; h=Date:To:From:Subject:Message-Id; b=VGDGfZvzuKjoPvH+OwIfO5oFaASNp0GVOQzp6hQcgSrG1rnPaFxBSxAG5HO0GGR0/b7gI3hZq4e1EyZL1kWHVMjr/uqCwZxzqkwyW8uR0mrBENLJN5btFjwuy7cMqA3/A+73rEh0FziNyoqldLDC9jSEoen6PV59KDbMqzaX1x8= 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=zr4+eFWG; 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="zr4+eFWG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8B8CDC4CEE3; Fri, 4 Jul 2025 20:20:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1751660402; bh=S3E1echE239FgnH8WWGAM6+Zc/ReCZ1qZhDc3/2Sp4M=; h=Date:To:From:Subject:From; b=zr4+eFWGrnicr5eCHpFNKHzW2WF4oOCq1gP3qTCW3mIYA7/FWN/uVqLf+TUTizCOc IA27VCdf01KDR449+1Ng2Ss1xI900NOAeKxddVB2xRygEwj7EGVnplpt3/JdwRqfC9 pGjJMaeMXxBWgw2XJtuf4KZkGoEIh/oMT/g+gedw= Date: Fri, 04 Jul 2025 13:20:01 -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-unstable branch Message-Id: <20250704202002.8B8CDC4CEE3@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-unstable 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-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: Kairui Song Subject: mm/shmem, swap: tidy up THP swapin checks Date: Sat, 5 Jul 2025 02:17:42 +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/20250704181748.63181-4-ryncsn@gmail.com Signed-off-by: Kairui Song Reviewed-by: 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 | 39 ++++++++++++++++++--------------------- 1 file changed, 18 insertions(+), 21 deletions(-) --- a/mm/shmem.c~mm-shmem-swap-tidy-up-thp-swapin-checks +++ a/mm/shmem.c @@ -1980,26 +1980,38 @@ 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); + 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); - gfp = limit_gfp_mask(huge_gfp, gfp); + 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 +2295,6 @@ 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 +2302,8 @@ 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-tidy-up-swap-entry-splitting.patch mm-shmem-swap-avoid-false-positive-swap-cache-lookup.patch mm-shmem-swap-never-use-swap-cache-and-readahead-for-swp_synchronous_io.patch mm-shmem-swap-simplify-swapin-path-and-result-handling.patch mm-shmem-swap-simplify-swap-entry-and-index-calculation-of-large-swapin.patch mm-shmem-swap-fix-major-fault-counting.patch