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 741812505CE for ; Sat, 2 Aug 2025 18:54:42 +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=1754160882; cv=none; b=BfTCtf/yVJZTIcipcLFKjYN2unmVothfXalA1DMAraJ3LPiZESOi3rMYl6jWXjgXKLkq3M20RRAdccRugGvIT6vcCuUwPwl+RoX6oRaihpDJdu2oIU1GrPEfbkx+ldpe5tfnUmLkPKDV6lzEtb7EZ/hQf6UUSbRKbffuU/UxX3c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754160882; c=relaxed/simple; bh=gb7SBq/+bsxr7Rw5cCXlcXNVDxhdPCC8so56MoMAmqA=; h=Date:To:From:Subject:Message-Id; b=lzYJBfWwahNcNQLAXGqmTigelgcf8exkk1jvqfxKIE4VeiermVd3QwQ9vLMxGpKKhbhE1cYAADAlrOLImtEB5zLLUbIpFuzeJPl+vP9qhKh775HoYbVNR9kaEH3HeaBsLPHdeBuZcBtEqdGVXUPhcu8CbnFxYd0vWXnoLK+/tGo= 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=AYGIaQUb; 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="AYGIaQUb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 49715C4CEEF; Sat, 2 Aug 2025 18:54:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1754160882; bh=gb7SBq/+bsxr7Rw5cCXlcXNVDxhdPCC8so56MoMAmqA=; h=Date:To:From:Subject:From; b=AYGIaQUb/7nkjQCFpYt1f+aaIVIWUaKMJRXo10F4cXhbx6eSfH2K/y45yf/QOJei/ CuNuVBIBB3y3kP+uYqp7CUQ5wtS83r6dCoSTvAvAJb/cav3dXB1Fuhrm5cM/Q4DLNK J2d8VCOTp0xbwzLQJart/uJvcM7Fr/85NLWZF34A= Date: Sat, 02 Aug 2025 11:54:41 -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: [merged mm-stable] mm-shmem-swap-never-use-swap-cache-and-readahead-for-swp_synchronous_io.patch removed from -mm tree Message-Id: <20250802185442.49715C4CEEF@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm/shmem, swap: never use swap cache and readahead for SWP_SYNCHRONOUS_IO has been removed from the -mm tree. Its filename was mm-shmem-swap-never-use-swap-cache-and-readahead-for-swp_synchronous_io.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: Kairui Song Subject: mm/shmem, swap: never use swap cache and readahead for SWP_SYNCHRONOUS_IO Date: Mon, 28 Jul 2025 15:53:03 +0800 For SWP_SYNCHRONOUS_IO devices, if a cache bypassing THP swapin failed due to reasons like memory pressure, partially conflicting swap cache or ZSWAP enabled, shmem will fallback to cached order 0 swapin. Right now the swap cache still has a non-trivial overhead, and readahead is not helpful for SWP_SYNCHRONOUS_IO devices, so we should always skip the readahead and swap cache even if the swapin falls back to order 0. So handle the fallback logic without falling back to the cached read. Link: https://lkml.kernel.org/r/20250728075306.12704-6-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 | 41 ++++++++++++++++++++++++++++------------- 1 file changed, 28 insertions(+), 13 deletions(-) --- a/mm/shmem.c~mm-shmem-swap-never-use-swap-cache-and-readahead-for-swp_synchronous_io +++ a/mm/shmem.c @@ -2019,6 +2019,7 @@ static struct folio *shmem_swap_alloc_fo struct shmem_inode_info *info = SHMEM_I(inode); int nr_pages = 1 << order; struct folio *new; + gfp_t alloc_gfp; void *shadow; /* @@ -2026,6 +2027,7 @@ static struct folio *shmem_swap_alloc_fo * limit chance of success with further cpuset and node constraints. */ gfp &= ~GFP_CONSTRAINT_MASK; + alloc_gfp = gfp; if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) { if (WARN_ON_ONCE(order)) return ERR_PTR(-EINVAL); @@ -2040,19 +2042,22 @@ static struct folio *shmem_swap_alloc_fo if ((vma && unlikely(userfaultfd_armed(vma))) || !zswap_never_enabled() || non_swapcache_batch(entry, nr_pages) != nr_pages) - return ERR_PTR(-EINVAL); + goto fallback; - gfp = limit_gfp_mask(vma_thp_gfp_mask(vma), gfp); + alloc_gfp = limit_gfp_mask(vma_thp_gfp_mask(vma), gfp); + } +retry: + new = shmem_alloc_folio(alloc_gfp, order, info, index); + if (!new) { + new = ERR_PTR(-ENOMEM); + goto fallback; } - - new = shmem_alloc_folio(gfp, order, info, index); - if (!new) - return ERR_PTR(-ENOMEM); if (mem_cgroup_swapin_charge_folio(new, vma ? vma->vm_mm : NULL, - gfp, entry)) { + alloc_gfp, entry)) { folio_put(new); - return ERR_PTR(-ENOMEM); + new = ERR_PTR(-ENOMEM); + goto fallback; } /* @@ -2067,7 +2072,9 @@ static struct folio *shmem_swap_alloc_fo */ if (swapcache_prepare(entry, nr_pages)) { folio_put(new); - return ERR_PTR(-EEXIST); + new = ERR_PTR(-EEXIST); + /* Try smaller folio to avoid cache conflict */ + goto fallback; } __folio_set_locked(new); @@ -2081,6 +2088,15 @@ static struct folio *shmem_swap_alloc_fo folio_add_lru(new); swap_read_folio(new, NULL); return new; +fallback: + /* Order 0 swapin failed, nothing to fallback to, abort */ + if (!order) + return new; + entry.val += index - round_down(index, nr_pages); + alloc_gfp = gfp; + nr_pages = 1; + order = 0; + goto retry; } /* @@ -2350,13 +2366,12 @@ static int shmem_swapin_folio(struct ino } /* - * Fallback to swapin order-0 folio unless the swap entry - * already exists. + * Direct swapin handled order 0 fallback already, + * if it failed, abort. */ error = PTR_ERR(folio); folio = NULL; - if (error == -EEXIST) - goto failed; + goto failed; } /* _ Patches currently in -mm which might be from kasong@tencent.com are