From nobody Sat Feb 7 17:55:45 2026 Received: from out30-112.freemail.mail.aliyun.com (out30-112.freemail.mail.aliyun.com [115.124.30.112]) (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 83F9322154B for ; Fri, 19 Dec 2025 06:03:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.112 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766124191; cv=none; b=nmLY9ClJkc+gSrt5pE5Hg/54EPfbBhOK4uKl35T8o+KMKUSjx1T56FfjfLaycwP06wumDx4quLunDtBwhKeY1NOO4WpK+r4aOjNDskxnssIHKglfaKmWZ77+FmSCeuh8Zgt22c0uXpEI9kp1EeZp3JQFVTjluPs50IpH9dBdLfk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766124191; c=relaxed/simple; bh=XUSakoCi+Migu1TMyGy6Kb0zKvMjluQbwfNMh/gLo6M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Yj/xnm4p78VfsAtevf9aZbUNDHP/iz5n93frguSwCvfZ0CwzWafp0x5puaT8XXkTghQAhghyJ3wYc6p7ClDV1V+snNU1pxIZL3Vzzm9OeDENrf9/lSGg4ECUIhn9sT1m6rTzKe1ikHlUTLhEPznn1ABs0Pt6cEB9bGPmXVW+KvM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=lW5lGOr1; arc=none smtp.client-ip=115.124.30.112 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="lW5lGOr1" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1766124185; h=From:To:Subject:Date:Message-ID:MIME-Version; bh=q9nk8p1gEgDEfDsl6eOexaGSc82IGm5TOYQhnxb8huI=; b=lW5lGOr1Wu8zNKf6GY17TPdR4TKbyPN1Jv/vyY7Xw6ACLGQLrL0hgr7XaaCjRE2JcPmbZb8dT1330BOdmaFIP3IBxmTiWA7UBFzzz27H94vbtOiT4ieBb5a51poQYhLIiTTXiGQhZBDzxoBw9vEAbFCzmnt8fQJ7XQnX0aOn5Mc= Received: from localhost(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0WvBZ2GG_1766124182 cluster:ay36) by smtp.aliyun-inc.com; Fri, 19 Dec 2025 14:03:03 +0800 From: Baolin Wang To: akpm@linux-foundation.org, david@kernel.org, catalin.marinas@arm.com, will@kernel.org Cc: lorenzo.stoakes@oracle.com, ryan.roberts@arm.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, riel@surriel.com, harry.yoo@oracle.com, jannh@google.com, willy@infradead.org, baohua@kernel.org, dev.jain@arm.com, baolin.wang@linux.alibaba.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 1/5] mm: rmap: support batched checks of the references for large folios Date: Fri, 19 Dec 2025 14:02:51 +0800 Message-ID: <24b9d33acad627997febe9b61d398fc53739a333.1766121341.git.baolin.wang@linux.alibaba.com> X-Mailer: git-send-email 2.43.7 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Currently, folio_referenced_one() always checks the young flag for each PTE sequentially, which is inefficient for large folios. This inefficiency is especially noticeable when reclaiming clean file-backed large folios, where folio_referenced() is observed as a significant performance hotspot. Moreover, on Arm64 architecture, which supports contiguous PTEs, there is a= lready an optimization to clear the young flags for PTEs within a contiguous range. However, this is not sufficient. We can extend this to perform batched oper= ations for the entire large folio (which might exceed the contiguous range: CONT_P= TE_SIZE). Introduce a new API: clear_flush_young_ptes() to facilitate batched checking of the young flags and flushing TLB entries, thereby improving performance during large folio reclamation. And it will be overridden by the architectu= re that implements a more efficient batch operation in the following patches. Signed-off-by: Baolin Wang --- include/linux/mmu_notifier.h | 9 +++++---- include/linux/pgtable.h | 35 +++++++++++++++++++++++++++++++++++ mm/rmap.c | 29 +++++++++++++++++++++++++++-- 3 files changed, 67 insertions(+), 6 deletions(-) diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h index d1094c2d5fb6..be594b274729 100644 --- a/include/linux/mmu_notifier.h +++ b/include/linux/mmu_notifier.h @@ -515,16 +515,17 @@ static inline void mmu_notifier_range_init_owner( range->owner =3D owner; } =20 -#define ptep_clear_flush_young_notify(__vma, __address, __ptep) \ +#define ptep_clear_flush_young_notify(__vma, __address, __ptep, __nr) \ ({ \ int __young; \ struct vm_area_struct *___vma =3D __vma; \ unsigned long ___address =3D __address; \ - __young =3D ptep_clear_flush_young(___vma, ___address, __ptep); \ + unsigned int ___nr =3D __nr; \ + __young =3D clear_flush_young_ptes(___vma, ___address, __ptep, ___nr); \ __young |=3D mmu_notifier_clear_flush_young(___vma->vm_mm, \ ___address, \ ___address + \ - PAGE_SIZE); \ + nr * PAGE_SIZE); \ __young; \ }) =20 @@ -650,7 +651,7 @@ static inline void mmu_notifier_subscriptions_destroy(s= truct mm_struct *mm) =20 #define mmu_notifier_range_update_to_read_only(r) false =20 -#define ptep_clear_flush_young_notify ptep_clear_flush_young +#define ptep_clear_flush_young_notify clear_flush_young_ptes #define pmdp_clear_flush_young_notify pmdp_clear_flush_young #define ptep_clear_young_notify ptep_test_and_clear_young #define pmdp_clear_young_notify pmdp_test_and_clear_young diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index b13b6f42be3c..7e659f4171e2 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -947,6 +947,41 @@ static inline void wrprotect_ptes(struct mm_struct *mm= , unsigned long addr, } #endif =20 +#ifndef clear_flush_young_ptes +/** + * clear_flush_young_ptes - Clear the access bit and perform a TLB flush f= or PTEs + * that map consecutive pages of the same folio. + * @vma: The virtual memory area the pages are mapped into. + * @addr: Address the first page is mapped at. + * @ptep: Page table pointer for the first entry. + * @nr: Number of entries to clear access bit. + * + * May be overridden by the architecture; otherwise, implemented as a simp= le + * loop over ptep_clear_flush_young(). + * + * Note that PTE bits in the PTE range besides the PFN can differ. For exa= mple, + * some PTEs might be write-protected. + * + * Context: The caller holds the page table lock. The PTEs map consecutive + * pages that belong to the same folio. The PTEs are all in the same PMD. + */ +static inline int clear_flush_young_ptes(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, + unsigned int nr) +{ + int young; + + young =3D ptep_clear_flush_young(vma, addr, ptep); + while (--nr) { + ptep++; + addr +=3D PAGE_SIZE; + young |=3D ptep_clear_flush_young(vma, addr, ptep); + } + + return young; +} +#endif + /* * On some architectures hardware does not set page access bit when access= ing * memory page, it is responsibility of software setting this bit. It brin= gs diff --git a/mm/rmap.c b/mm/rmap.c index d6799afe1114..a0fc05f5966f 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -827,9 +827,11 @@ static bool folio_referenced_one(struct folio *folio, struct folio_referenced_arg *pra =3D arg; DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, address, 0); int ptes =3D 0, referenced =3D 0; + unsigned int nr; =20 while (page_vma_mapped_walk(&pvmw)) { address =3D pvmw.address; + nr =3D 1; =20 if (vma->vm_flags & VM_LOCKED) { ptes++; @@ -874,9 +876,24 @@ static bool folio_referenced_one(struct folio *folio, if (lru_gen_look_around(&pvmw)) referenced++; } else if (pvmw.pte) { + if (folio_test_large(folio)) { + unsigned long end_addr =3D + pmd_addr_end(address, vma->vm_end); + unsigned int max_nr =3D + (end_addr - address) >> PAGE_SHIFT; + pte_t pteval =3D ptep_get(pvmw.pte); + + nr =3D folio_pte_batch(folio, pvmw.pte, + pteval, max_nr); + } + + ptes +=3D nr; if (ptep_clear_flush_young_notify(vma, address, - pvmw.pte)) + pvmw.pte, nr)) referenced++; + /* Skip the batched PTEs */ + pvmw.pte +=3D nr - 1; + pvmw.address +=3D (nr - 1) * PAGE_SIZE; } else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) { if (pmdp_clear_flush_young_notify(vma, address, pvmw.pmd)) @@ -886,7 +903,15 @@ static bool folio_referenced_one(struct folio *folio, WARN_ON_ONCE(1); } =20 - pra->mapcount--; + pra->mapcount -=3D nr; + /* + * If we are sure that we batched the entire folio, + * we can just optimize and stop right here. + */ + if (ptes =3D=3D pvmw.nr_pages) { + page_vma_mapped_walk_done(&pvmw); + break; + } } =20 if (referenced) --=20 2.47.3 From nobody Sat Feb 7 17:55:45 2026 Received: from out30-119.freemail.mail.aliyun.com (out30-119.freemail.mail.aliyun.com [115.124.30.119]) (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 A207323D7FF for ; Fri, 19 Dec 2025 06:03:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.119 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766124192; cv=none; b=QOrrZIR7IdShI8AHojdhqDNcn/9MXbLBltb+XkYWv1YsdJRGGHt3lTYkII/S+5iKm18+yIyZbidpR0DhM5rNxKMlP/sXyQtEPd/w4Gh3prGvwbW+kD0BnH86wKuGTsagPmcmAnF64cEh/4F7UalTP8IZqCr0UtqUjiS20fK4z9g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766124192; c=relaxed/simple; bh=mqrLN8XeN/fcSfBXFbNfZKeOpM9SeOccw7eVUZvfxdk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FYEQEXO5G9TK1YqXLpABmql3fjqbxfhUldP3OXaGbESy25AM3O5mRR5hhBhoQsb1xyKoQpn3ecHsztM54tTP+0pY1AL8CmwOWHgKJg7KM+20RbSFPsbTcMaqC7PEXgk6EhbdFMyPvjEWCY5MU8tKLRoI61tXbjzjXJ6q5ytKZV0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=rd5QCV6j; arc=none smtp.client-ip=115.124.30.119 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="rd5QCV6j" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1766124187; h=From:To:Subject:Date:Message-ID:MIME-Version; bh=cx0gBasjhco1rzxEYEyLJsADnhZt08xD0/YXyn0KOfU=; b=rd5QCV6jEHVtddRkvbXhN6wRi2bJQPZne+D0Rv25WV8jpBdjBnumcsrT5Ilx3hJCtB1LExOenINCp/Nn5r2aICHwvApyUPMpfOZCKoeLn8xPRaYSnNkOfSDWmtgu9npHk8kQnr+DP3PAsXTrrz7osm1khUoPzGgKNcYl4++K3yY= Received: from localhost(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0WvBV0.._1766124184 cluster:ay36) by smtp.aliyun-inc.com; Fri, 19 Dec 2025 14:03:05 +0800 From: Baolin Wang To: akpm@linux-foundation.org, david@kernel.org, catalin.marinas@arm.com, will@kernel.org Cc: lorenzo.stoakes@oracle.com, ryan.roberts@arm.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, riel@surriel.com, harry.yoo@oracle.com, jannh@google.com, willy@infradead.org, baohua@kernel.org, dev.jain@arm.com, baolin.wang@linux.alibaba.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 2/5] arm64: mm: factor out the address and ptep alignment into a new helper Date: Fri, 19 Dec 2025 14:02:52 +0800 Message-ID: <8606e13617bb8ec302806a6ebdbe5f680e4466a4.1766121341.git.baolin.wang@linux.alibaba.com> X-Mailer: git-send-email 2.43.7 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Factor out the contpte block's address and ptep alignment into a new helper, and will be reused in the following patch. No functional changes. Signed-off-by: Baolin Wang --- arch/arm64/mm/contpte.c | 29 +++++++++++++++++++++-------- 1 file changed, 21 insertions(+), 8 deletions(-) diff --git a/arch/arm64/mm/contpte.c b/arch/arm64/mm/contpte.c index c0557945939c..c73e77207584 100644 --- a/arch/arm64/mm/contpte.c +++ b/arch/arm64/mm/contpte.c @@ -26,6 +26,26 @@ static inline pte_t *contpte_align_down(pte_t *ptep) return PTR_ALIGN_DOWN(ptep, sizeof(*ptep) * CONT_PTES); } =20 +static inline pte_t *contpte_align_addr_ptep(unsigned long *start, + unsigned long *end, pte_t *ptep, + unsigned int nr) +{ + /* + * Note: caller must ensure these nr PTEs are consecutive (present) + * PTEs that map consecutive pages of the same large folio within a + * single VMA and a single page table. + */ + if (pte_cont(__ptep_get(ptep + nr - 1))) + *end =3D ALIGN(*end, CONT_PTE_SIZE); + + if (pte_cont(__ptep_get(ptep))) { + *start =3D ALIGN_DOWN(*start, CONT_PTE_SIZE); + ptep =3D contpte_align_down(ptep); + } + + return ptep; +} + static void contpte_try_unfold_partial(struct mm_struct *mm, unsigned long= addr, pte_t *ptep, unsigned int nr) { @@ -569,14 +589,7 @@ void contpte_clear_young_dirty_ptes(struct vm_area_str= uct *vma, unsigned long start =3D addr; unsigned long end =3D start + nr * PAGE_SIZE; =20 - if (pte_cont(__ptep_get(ptep + nr - 1))) - end =3D ALIGN(end, CONT_PTE_SIZE); - - if (pte_cont(__ptep_get(ptep))) { - start =3D ALIGN_DOWN(start, CONT_PTE_SIZE); - ptep =3D contpte_align_down(ptep); - } - + ptep =3D contpte_align_addr_ptep(&start, &end, ptep, nr); __clear_young_dirty_ptes(vma, start, ptep, (end - start) / PAGE_SIZE, fla= gs); } EXPORT_SYMBOL_GPL(contpte_clear_young_dirty_ptes); --=20 2.47.3 From nobody Sat Feb 7 17:55:45 2026 Received: from out30-133.freemail.mail.aliyun.com (out30-133.freemail.mail.aliyun.com [115.124.30.133]) (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 BF0D22D9EE7 for ; Fri, 19 Dec 2025 06:03:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.133 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766124198; cv=none; b=Au51L0vnwsz83GgEZN6GHdOnAB9pBRQ0g3HIl+/fDcYyJ3NRgYPnvmyxZjqNOEe0XMWPyV3HFsGGIICXRXRl6nWaHk/JkjIbcwzMASUfp2Hm9qqjDlYVPDZ5KryTOuK6h9YFTnweUeQZlISckuJMOvmofkgYOBxn4UHwmRSTj/w= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766124198; c=relaxed/simple; bh=nHnCxL8c1tehaAOpgjiLpvD99SYHolbZD+B5Z4K2MMc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=T8zVCbt+/XzVIKEuKvCA7A3Dl0W2GQVWQsPq3ADmfy1QS6w5xdbe5R6KCHIT+9HGLMuFL1I453Uzxoi0+gkAF3nSYAN5kO00KgM7tRCNCg+LW+WKiqUZD09W8ODGzpJuYmyjw9oLIUXuU9wTXWCYLP1v0/i2cejVJHi9J8Ns9gQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=MPrmVe2s; arc=none smtp.client-ip=115.124.30.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="MPrmVe2s" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1766124188; h=From:To:Subject:Date:Message-ID:MIME-Version; bh=Umqy+CieAvau1WCrcGlezOzuDWrvWtrJZghCjmaOXp0=; b=MPrmVe2swWEM/mWhhjQll5XSLRICHgZyd9ABTLim93PaNFPizxY/CVk2uxuA9PZyQOWbkUB47DFfG9qW6K2N5P5b9MYqKH+x8cBaaL8FdjHSGYg1HEO5o5Gj/65fV376BfAKGQD3DD59BSqc6mHkMzN+8GeH6ICwcs12c3ExERA= Received: from localhost(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0WvBV0.x_1766124186 cluster:ay36) by smtp.aliyun-inc.com; Fri, 19 Dec 2025 14:03:06 +0800 From: Baolin Wang To: akpm@linux-foundation.org, david@kernel.org, catalin.marinas@arm.com, will@kernel.org Cc: lorenzo.stoakes@oracle.com, ryan.roberts@arm.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, riel@surriel.com, harry.yoo@oracle.com, jannh@google.com, willy@infradead.org, baohua@kernel.org, dev.jain@arm.com, baolin.wang@linux.alibaba.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 3/5] arm64: mm: support batch clearing of the young flag for large folios Date: Fri, 19 Dec 2025 14:02:53 +0800 Message-ID: <0fc85ceb11b26e2fd0bc164df0391c7117881c61.1766121341.git.baolin.wang@linux.alibaba.com> X-Mailer: git-send-email 2.43.7 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Currently, contpte_ptep_test_and_clear_young() and contpte_ptep_clear_flush= _young() only clear the young flag and flush TLBs for PTEs within the contiguous ran= ge. To support batch PTE operations for other sized large folios in the followi= ng patches, adding a new parameter to specify the number of PTEs that map cons= ecutive pages of the same large folio in a single VMA and a single page table. While we are at it, rename the functions to maintain consistency with other contpte_*() functions. Signed-off-by: Baolin Wang --- arch/arm64/include/asm/pgtable.h | 12 ++++++------ arch/arm64/mm/contpte.c | 33 ++++++++++++++++++-------------- 2 files changed, 25 insertions(+), 20 deletions(-) diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgta= ble.h index 0944e296dd4a..9086753f68b4 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -1679,10 +1679,10 @@ extern void contpte_clear_full_ptes(struct mm_struc= t *mm, unsigned long addr, extern pte_t contpte_get_and_clear_full_ptes(struct mm_struct *mm, unsigned long addr, pte_t *ptep, unsigned int nr, int full); -extern int contpte_ptep_test_and_clear_young(struct vm_area_struct *vma, - unsigned long addr, pte_t *ptep); -extern int contpte_ptep_clear_flush_young(struct vm_area_struct *vma, - unsigned long addr, pte_t *ptep); +int contpte_test_and_clear_young_ptes(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, unsigned int nr); +int contpte_clear_flush_young_ptes(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, unsigned int nr); extern void contpte_wrprotect_ptes(struct mm_struct *mm, unsigned long add= r, pte_t *ptep, unsigned int nr); extern int contpte_ptep_set_access_flags(struct vm_area_struct *vma, @@ -1854,7 +1854,7 @@ static inline int ptep_test_and_clear_young(struct vm= _area_struct *vma, if (likely(!pte_valid_cont(orig_pte))) return __ptep_test_and_clear_young(vma, addr, ptep); =20 - return contpte_ptep_test_and_clear_young(vma, addr, ptep); + return contpte_test_and_clear_young_ptes(vma, addr, ptep, CONT_PTES); } =20 #define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH @@ -1866,7 +1866,7 @@ static inline int ptep_clear_flush_young(struct vm_ar= ea_struct *vma, if (likely(!pte_valid_cont(orig_pte))) return __ptep_clear_flush_young(vma, addr, ptep); =20 - return contpte_ptep_clear_flush_young(vma, addr, ptep); + return contpte_clear_flush_young_ptes(vma, addr, ptep, CONT_PTES); } =20 #define wrprotect_ptes wrprotect_ptes diff --git a/arch/arm64/mm/contpte.c b/arch/arm64/mm/contpte.c index c73e77207584..c0f89af605e0 100644 --- a/arch/arm64/mm/contpte.c +++ b/arch/arm64/mm/contpte.c @@ -508,8 +508,9 @@ pte_t contpte_get_and_clear_full_ptes(struct mm_struct = *mm, } EXPORT_SYMBOL_GPL(contpte_get_and_clear_full_ptes); =20 -int contpte_ptep_test_and_clear_young(struct vm_area_struct *vma, - unsigned long addr, pte_t *ptep) +int contpte_test_and_clear_young_ptes(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, + unsigned int nr) { /* * ptep_clear_flush_young() technically requires us to clear the access @@ -518,41 +519,45 @@ int contpte_ptep_test_and_clear_young(struct vm_area_= struct *vma, * contig range when the range is covered by a single folio, we can get * away with clearing young for the whole contig range here, so we avoid * having to unfold. + * + * The 'nr' means consecutive (present) PTEs that map consecutive pages + * of the same large folio in a single VMA and a single page table. */ =20 + unsigned long end =3D addr + nr * PAGE_SIZE; int young =3D 0; - int i; =20 - ptep =3D contpte_align_down(ptep); - addr =3D ALIGN_DOWN(addr, CONT_PTE_SIZE); - - for (i =3D 0; i < CONT_PTES; i++, ptep++, addr +=3D PAGE_SIZE) + ptep =3D contpte_align_addr_ptep(&addr, &end, ptep, nr); + for (; addr !=3D end; ptep++, addr +=3D PAGE_SIZE) young |=3D __ptep_test_and_clear_young(vma, addr, ptep); =20 return young; } -EXPORT_SYMBOL_GPL(contpte_ptep_test_and_clear_young); +EXPORT_SYMBOL_GPL(contpte_test_and_clear_young_ptes); =20 -int contpte_ptep_clear_flush_young(struct vm_area_struct *vma, - unsigned long addr, pte_t *ptep) +int contpte_clear_flush_young_ptes(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, + unsigned int nr) { int young; =20 - young =3D contpte_ptep_test_and_clear_young(vma, addr, ptep); + young =3D contpte_test_and_clear_young_ptes(vma, addr, ptep, nr); =20 if (young) { + unsigned long end =3D addr + nr * PAGE_SIZE; + + contpte_align_addr_ptep(&addr, &end, ptep, nr); /* * See comment in __ptep_clear_flush_young(); same rationale for * eliding the trailing DSB applies here. */ - addr =3D ALIGN_DOWN(addr, CONT_PTE_SIZE); - __flush_tlb_range_nosync(vma->vm_mm, addr, addr + CONT_PTE_SIZE, + __flush_tlb_range_nosync(vma->vm_mm, addr, end, PAGE_SIZE, true, 3); } =20 return young; } -EXPORT_SYMBOL_GPL(contpte_ptep_clear_flush_young); +EXPORT_SYMBOL_GPL(contpte_clear_flush_young_ptes); =20 void contpte_wrprotect_ptes(struct mm_struct *mm, unsigned long addr, pte_t *ptep, unsigned int nr) --=20 2.47.3 From nobody Sat Feb 7 17:55:45 2026 Received: from out30-113.freemail.mail.aliyun.com (out30-113.freemail.mail.aliyun.com [115.124.30.113]) (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 548982D8797 for ; Fri, 19 Dec 2025 06:03:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.113 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766124197; cv=none; b=lF7bavc8Jvcb2WsWWl66cny1y7TyJXIZt8bT7TdalhdJAMG8JdODQyb5cU+/06RyBxLNSnk9I2TZS432IEAT6b8G7qTTAvGBUz+EKDPEnwyafa6cq6cNj6peTEVELgm81hin4xbyLlcmf4p2GEh9vM861HEKSJxl7mrym7ADkeg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766124197; c=relaxed/simple; bh=c+KlqA1uruULKhAZf+QtCVMl6um+QWNXfA+9KAoQjiI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=I5VKITc1cjss7HNEGZVzgelleFTZnF/JFoGvYaoPyiANKivkPO/FjxXXctT6aaK3kEkC5X39IRf19F4rJOFxub5hchktCNThhrHA9xxSACbPyJzfCH4HVFoG4yNgPBTFbeyrEUGPKjId6YB6JphxdZUxyuCoCmxXiF4tIrW9J5w= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=LMjS0eHn; arc=none smtp.client-ip=115.124.30.113 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="LMjS0eHn" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1766124191; h=From:To:Subject:Date:Message-ID:MIME-Version; bh=U4MSwdop2NxYytb9NkJpD0u6xgL6N8xbLEBChXF1nyE=; b=LMjS0eHnpR5a/+0HB7vaaEcgPkTdB+GGvR2A2fCgsGF2ga0p49eF1LnyrjEWaNIqEl87APlxmhxczUMuKhmlWWsXXxAXOvlnWykLlHBiSLFZjRIFp+KGtvAYYgzAlir8jzAbHA+5oyY/jciTF/CHJuJSkhRCYWTlTQ/KOMwuWQE= Received: from localhost(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0WvBfipZ_1766124187 cluster:ay36) by smtp.aliyun-inc.com; Fri, 19 Dec 2025 14:03:08 +0800 From: Baolin Wang To: akpm@linux-foundation.org, david@kernel.org, catalin.marinas@arm.com, will@kernel.org Cc: lorenzo.stoakes@oracle.com, ryan.roberts@arm.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, riel@surriel.com, harry.yoo@oracle.com, jannh@google.com, willy@infradead.org, baohua@kernel.org, dev.jain@arm.com, baolin.wang@linux.alibaba.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 4/5] arm64: mm: implement the architecture-specific clear_flush_young_ptes() Date: Fri, 19 Dec 2025 14:02:54 +0800 Message-ID: <511d0f46d5f02f5e1ecc67318bc2ce8997208c85.1766121341.git.baolin.wang@linux.alibaba.com> X-Mailer: git-send-email 2.43.7 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Implement the Arm64 architecture-specific clear_flush_young_ptes() to enable batched checking of young flags and TLB flushing, improving performance dur= ing large folio reclamation. Performance testing: Allocate 10G clean file-backed folios by mmap() in a memory cgroup, and try= to reclaim 8G file-backed folios via the memory.reclaim interface. I can obser= ve 33% performance improvement on my Arm64 32-core server (and 10%+ improvement on my X86 machine). Meanwhile, the hotspot folio_check_references() dropped from approximately 35% to around 5%. W/o patchset: real 0m1.518s user 0m0.000s sys 0m1.518s W/ patchset: real 0m1.018s user 0m0.000s sys 0m1.018s Signed-off-by: Baolin Wang --- arch/arm64/include/asm/pgtable.h | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgta= ble.h index 9086753f68b4..c57eda654d9b 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -1869,6 +1869,17 @@ static inline int ptep_clear_flush_young(struct vm_a= rea_struct *vma, return contpte_clear_flush_young_ptes(vma, addr, ptep, CONT_PTES); } =20 +#define clear_flush_young_ptes clear_flush_young_ptes +static inline int clear_flush_young_ptes(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, + unsigned int nr) +{ + if (likely(nr =3D=3D 1 && !pte_cont(__ptep_get(ptep)))) + return __ptep_clear_flush_young(vma, addr, ptep); + + return contpte_clear_flush_young_ptes(vma, addr, ptep, nr); +} + #define wrprotect_ptes wrprotect_ptes static __always_inline void wrprotect_ptes(struct mm_struct *mm, unsigned long addr, pte_t *ptep, unsigned int nr) --=20 2.47.3 From nobody Sat Feb 7 17:55:45 2026 Received: from out30-124.freemail.mail.aliyun.com (out30-124.freemail.mail.aliyun.com [115.124.30.124]) (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 BF04E2D73BE for ; Fri, 19 Dec 2025 06:03:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766124198; cv=none; b=CPk2v4mH/OpNrQZ7gR5ARZaJ6vo4QOJraKtp8eRcHbcCjgP8IyYl+v+6qryJpCJgiZUuHQqT5kk7ZoFIDIkQIO+5PLY6kpV45oVgtfy3EhFHiV7HIJrTM7zUA6Om0KHJ47OtjrvFO+NfzuSdAXviBS8DDEW1r9vf39SQb+8mABU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766124198; c=relaxed/simple; bh=VXh/o28OXwT6EP2TyzG92ME41my07jcdRQ29RZ/in6Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=S4m12C+sOLA2w3tE1DdZVFbf0D63X4B2vvp9OIUwiRd7+2G87bmDlAA7iWxWgUeaxW686jjjdkGC9785zQJorgRSFP8q94ek1kTcTiAmXhQoE5j0OLhRzeZYrV95mIzBQH4k+3ER8JkpfFn0uF5dhif/zDrlwwzR2dSb8+cYA9s= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=i3KzONl4; arc=none smtp.client-ip=115.124.30.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="i3KzONl4" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1766124191; h=From:To:Subject:Date:Message-ID:MIME-Version; bh=L8grYI0Jwq9L4Vxa84m+Wpr8ZQOY0j4j8t2HLaHt6zk=; b=i3KzONl4DQZE26Iutu0WKpZ28yeA38BsuLgecovePZr/G8qrWU5h1q5QRiD+diuZkhSmqioUMNIdMv05XoPpPxb8n8n14MYxPlpRC/rAqdvUdNuXPAvqHT6vzjm/5ROMTik4BA5J/Mv+fCEu+1fF650Q1bLRgKF0x0CqvFMeMGw= Received: from localhost(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0WvBZ2Kv_1766124189 cluster:ay36) by smtp.aliyun-inc.com; Fri, 19 Dec 2025 14:03:09 +0800 From: Baolin Wang To: akpm@linux-foundation.org, david@kernel.org, catalin.marinas@arm.com, will@kernel.org Cc: lorenzo.stoakes@oracle.com, ryan.roberts@arm.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, riel@surriel.com, harry.yoo@oracle.com, jannh@google.com, willy@infradead.org, baohua@kernel.org, dev.jain@arm.com, baolin.wang@linux.alibaba.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 5/5] mm: rmap: support batched unmapping for file large folios Date: Fri, 19 Dec 2025 14:02:55 +0800 Message-ID: X-Mailer: git-send-email 2.43.7 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Similar to folio_referenced_one(), we can apply batched unmapping for file large folios to optimize the performance of file folios reclamation. Barry previously implemented batched unmapping for lazyfree anonymous large folios[1] and did not further optimize anonymous large folios or file-backed large folios at that stage. As for file-backed large folios, the batched unmapping support is relatively straightforward, as we only need to clear the consecutive (present) PTE entries for file-backed large folios. Performance testing: Allocate 10G clean file-backed folios by mmap() in a memory cgroup, and try= to reclaim 8G file-backed folios via the memory.reclaim interface. I can obser= ve 75% performance improvement on my Arm64 32-core server (and 50%+ improvement on my X86 machine) with this patch. W/o patch: real 0m1.018s user 0m0.000s sys 0m1.018s W/ patch: real 0m0.249s user 0m0.000s sys 0m0.249s [1] https://lore.kernel.org/all/20250214093015.51024-4-21cnbao@gmail.com/T/= #u Acked-by: Barry Song Signed-off-by: Baolin Wang --- mm/rmap.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/mm/rmap.c b/mm/rmap.c index a0fc05f5966f..7482121d4e92 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1862,9 +1862,10 @@ static inline unsigned int folio_unmap_pte_batch(str= uct folio *folio, end_addr =3D pmd_addr_end(addr, vma->vm_end); max_nr =3D (end_addr - addr) >> PAGE_SHIFT; =20 - /* We only support lazyfree batching for now ... */ - if (!folio_test_anon(folio) || folio_test_swapbacked(folio)) + /* We only support lazyfree or file folios batching for now ... */ + if (folio_test_anon(folio) && folio_test_swapbacked(folio)) return 1; + if (pte_unused(pte)) return 1; =20 @@ -2230,7 +2231,7 @@ static bool try_to_unmap_one(struct folio *folio, str= uct vm_area_struct *vma, * * See Documentation/mm/mmu_notifier.rst */ - dec_mm_counter(mm, mm_counter_file(folio)); + add_mm_counter(mm, mm_counter_file(folio), -nr_pages); } discard: if (unlikely(folio_test_hugetlb(folio))) { --=20 2.47.3