From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 593FD344056 for ; Tue, 10 Mar 2026 08:50:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773132615; cv=none; b=Ev1Ed7lcudThd8UXLbPBBxRsRY3/Vo3tlrcfTe8IUru0y78hn8bOHsSKajI6L6pElSt59tDcLC1yhfTkV1/GVka7Bo4w5qt+IyBKHc7dXSuH/l4nD5RX9jpd0oTrxSb6sqTDlaSwEcVIISxskdMZDKOEZsx9voQYOSgyde0mRyk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773132615; c=relaxed/simple; bh=uk4TNd/OfcJ0s1Zc1ubIfTFoKgqsRFbl+2+rCeze4SI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Y6gAfNhinl1lFRaQUTBxr17JnvgBoT+iUdo2fCPIdH52iTmf5d+rWBJgWMfJEGWFDHGK7qW634X7pISvuXIjYfGRLMNU8MdM3FTn506PN831WIduRb5jdux6+e0WFqQ/URVNerhkHljvuFYROI/wXOy/HzoGrrAazDaP1wHVCBc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8CB9B169C; Tue, 10 Mar 2026 01:50:07 -0700 (PDT) Received: from [10.164.19.59] (unknown [10.164.19.59]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 02EFD3F7BD; Tue, 10 Mar 2026 01:50:04 -0700 (PDT) Message-ID: <373b96e7-fda3-4ea2-8089-521dba064307@arm.com> Date: Tue, 10 Mar 2026 14:20:02 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 7/9] mm/swapfile: Make folio_put_swap batchable To: Kairui Song Cc: akpm@linux-foundation.org, axelrasmussen@google.com, yuanchu@google.com, david@kernel.org, hughd@google.com, chrisl@kernel.org, weixugc@google.com, ljs@kernel.org, Liam.Howlett@oracle.com, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, riel@surriel.com, harry.yoo@oracle.com, jannh@google.com, pfalcato@suse.de, baolin.wang@linux.alibaba.com, shikemeng@huaweicloud.com, nphamcs@gmail.com, bhe@redhat.com, baohua@kernel.org, youngjun.park@lge.com, ziy@nvidia.com, kas@kernel.org, willy@infradead.org, yuzhao@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, ryan.roberts@arm.com, anshuman.khandual@arm.com References: <20260310073013.4069309-1-dev.jain@arm.com> <20260310073013.4069309-8-dev.jain@arm.com> Content-Language: en-US From: Dev Jain In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 10/03/26 1:59 pm, Kairui Song wrote: > On Tue, Mar 10, 2026 at 3:47 PM Dev Jain wrote: >> >> Teach folio_put_swap to handle a batch of consecutive pages. Note that >> folio_put_swap already can handle a subset of this: nr_pages == 1 and >> nr_pages == folio_nr_pages(folio). Generalize this to any nr_pages. >> >> Currently we have a not-so-nice logic of passing in subpage == NULL if >> we mean to exercise the logic on the entire folio, and subpage != NULL if >> we want to exercise the logic on only that subpage. Remove this >> indirection, and explicitly pass subpage != NULL, and the number of >> pages required. >> >> Signed-off-by: Dev Jain >> --- >> mm/memory.c | 6 +++--- >> mm/rmap.c | 4 ++-- >> mm/shmem.c | 6 +++--- >> mm/swap.h | 5 +++-- >> mm/swapfile.c | 13 +++++-------- >> 5 files changed, 16 insertions(+), 18 deletions(-) >> >> diff --git a/mm/memory.c b/mm/memory.c >> index 768646c0b3b6a..8249a9b7083ab 100644 >> --- a/mm/memory.c >> +++ b/mm/memory.c >> @@ -5002,7 +5002,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) >> if (unlikely(folio != swapcache)) { >> folio_add_new_anon_rmap(folio, vma, address, RMAP_EXCLUSIVE); >> folio_add_lru_vma(folio, vma); >> - folio_put_swap(swapcache, NULL); >> + folio_put_swap(swapcache, folio_page(swapcache, 0), folio_nr_pages(swapcache)); >> } else if (!folio_test_anon(folio)) { >> /* >> * We currently only expect !anon folios that are fully >> @@ -5011,12 +5011,12 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) >> VM_WARN_ON_ONCE_FOLIO(folio_nr_pages(folio) != nr_pages, folio); >> VM_WARN_ON_ONCE_FOLIO(folio_mapped(folio), folio); >> folio_add_new_anon_rmap(folio, vma, address, rmap_flags); >> - folio_put_swap(folio, NULL); >> + folio_put_swap(folio, folio_page(folio, 0), folio_nr_pages(folio)); >> } else { >> VM_WARN_ON_ONCE(nr_pages != 1 && nr_pages != folio_nr_pages(folio)); >> folio_add_anon_rmap_ptes(folio, page, nr_pages, vma, address, >> rmap_flags); >> - folio_put_swap(folio, nr_pages == 1 ? page : NULL); >> + folio_put_swap(folio, page, nr_pages); >> } >> >> VM_BUG_ON(!folio_test_anon(folio) || >> diff --git a/mm/rmap.c b/mm/rmap.c >> index f6d5b187cf09b..42f6b00cced01 100644 >> --- a/mm/rmap.c >> +++ b/mm/rmap.c >> @@ -2293,7 +2293,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, >> * so we'll not check/care. >> */ >> if (arch_unmap_one(mm, vma, address, pteval) < 0) { >> - folio_put_swap(folio, subpage); >> + folio_put_swap(folio, subpage, 1); >> set_pte_at(mm, address, pvmw.pte, pteval); >> goto walk_abort; >> } >> @@ -2301,7 +2301,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, >> /* See folio_try_share_anon_rmap(): clear PTE first. */ >> if (anon_exclusive && >> folio_try_share_anon_rmap_pte(folio, subpage)) { >> - folio_put_swap(folio, subpage); >> + folio_put_swap(folio, subpage, 1); >> set_pte_at(mm, address, pvmw.pte, pteval); >> goto walk_abort; >> } >> diff --git a/mm/shmem.c b/mm/shmem.c >> index 86ee34c9b40b3..d9d216ea28ecb 100644 >> --- a/mm/shmem.c >> +++ b/mm/shmem.c >> @@ -1716,7 +1716,7 @@ int shmem_writeout(struct folio *folio, struct swap_iocb **plug, >> /* Swap entry might be erased by racing shmem_free_swap() */ >> if (!error) { >> shmem_recalc_inode(inode, 0, -nr_pages); >> - folio_put_swap(folio, NULL); >> + folio_put_swap(folio, folio_page(folio, 0), folio_nr_pages(folio)); > > I just realized that we already have a nr_pages variable available > here, maybe you can just use that? > > Feel free to ignore this if it might touch more code. > >> } >> >> /* >> @@ -2196,7 +2196,7 @@ static void shmem_set_folio_swapin_error(struct inode *inode, pgoff_t index, >> >> nr_pages = folio_nr_pages(folio); >> folio_wait_writeback(folio); >> - folio_put_swap(folio, NULL); >> + folio_put_swap(folio, folio_page(folio, 0), folio_nr_pages(folio)); >> swap_cache_del_folio(folio); >> /* >> * Don't treat swapin error folio as alloced. Otherwise inode->i_blocks >> @@ -2426,7 +2426,7 @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index, >> if (sgp == SGP_WRITE) >> folio_mark_accessed(folio); >> >> - folio_put_swap(folio, NULL); >> + folio_put_swap(folio, folio_page(folio, 0), folio_nr_pages(folio)); > > Same here, nr_pages seems good enough? Yup, thanks for your observation.