From nobody Sun Feb 8 21:27:54 2026 Received: from mail-pl1-f176.google.com (mail-pl1-f176.google.com [209.85.214.176]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E6F8B1635CA for ; Thu, 18 Apr 2024 13:44:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.176 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713447893; cv=none; b=WJhYREDlGzsTNXUZ7986ZXOqgkJ2ogFucxeL7CyISn5u6L23iGrCc7Q3DZCpZrHEkyB+cfR3Y2e/IzFL0kkFR7zbhn+e5qcl4OZ0mYWrcp+VkIFWmXZLfJsxzWTANitRUwzdqSEyp0Dd5qe403AyrpVlVenFeyMc6PIuMPGGF9k= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713447893; c=relaxed/simple; bh=vs6Beq48+kXNT5qsMOGp08C7Ii4wZzzBthcyqUl9lGQ=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=nN/6h94PItWrYu8WDQ0IyMOatLnx3CoqG0Fk3Qq7/2XVpOemLu0GpDTXc/VjU7yFX7sW9d2dFFZUjiJU4JuJZmoEBqZCgnNVkNTY5RVHwSMi6c1sl8FjRFKU/2d3LA0QN2T9WtqOfHvzLcncqxtSneYFVB0dNBZeS+9ZwGk+fdg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=fy1jzZe1; arc=none smtp.client-ip=209.85.214.176 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="fy1jzZe1" Received: by mail-pl1-f176.google.com with SMTP id d9443c01a7336-1e2178b2cf2so7522085ad.0 for ; Thu, 18 Apr 2024 06:44:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1713447891; x=1714052691; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=XITq4/hgHmAHZ0ZHlNrd2qmUtOIaf33ePb9J0ZwzOSE=; b=fy1jzZe1tieU44OGut/eAKh14C0yk5j3Pr/YZ+XNHWdNgSsVSfAd9mRpYwGKpmYnK2 1OntILn48k1YHKXBCZo6UhZIvgTb5YunBD35J2nGSGEfXDVJ7BGErOON8gXDLg3R1wzC 17en/J/SZ+y9SZrL0xg/yKq4u0i5PyWW3iPNszUwts7y3RrZ7v84PjA7CQu7uDOmJj3v Bol8+mjXtzDM9pKnvgNauVlJgEnLkBF8hzg1ntM8lk1RYhykrNMu6U4YBjN4ZQABpqa6 XH8FdMnJSgE3nPKKryn9mbfToRs/DKkczDy0LY+o0dJXAzL648/v5Je+EkmYA++o+VPe p9qw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1713447891; x=1714052691; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=XITq4/hgHmAHZ0ZHlNrd2qmUtOIaf33ePb9J0ZwzOSE=; b=N1BMGNljkWRgnVt44DlDFrEzRuA54t1A/N76NNO5bVLdKi824YxLj/pdaLS+134KvI 9sNh2KiYD8XlSHKwsG75hk2FDIayBLaWNGv7xx3s9+ggGjYeDCieEKBQIa5lDk90PiX/ bVmci+QIf3rYJAwp01SL8jXCIdAiIWqIvlMDi7v7M1DYXj/zY3FiAdW2m8sI72mgU7EJ fCyTIwIeacKrHZNvYy4U/5pWXBvx1lSYk3WUTximBjz3H/8mEccDbH9Jib08s23ah41O KxOevsxFTxuUGJKWf84xppybcZGd4vgodsJV1QVszSws668X1aTFQFrCMpXGEKUbBv6k SmKQ== X-Forwarded-Encrypted: i=1; AJvYcCXdtxMCRcNOxPQkkVLs4lT/iERWZAkguyf0tlJZ8jVsipaAiXvFsvo2FuzRUBlWrWCq/e9yi0EfHIO+1VH9oCV0KJ1FlkzYe5tcT6l8 X-Gm-Message-State: AOJu0Yx5eRpZy85SUmxifyQcNHb1ZDvhFQbmIlXpQkbKwEuJV8CXbJs3 YJzhdkNXhGHS2ZLHpja/2GvM28LMeunbgLOZcUxD2ZA1vuZFfA3E X-Google-Smtp-Source: AGHT+IFMvPYbcwWGZBEI/RPL6zIG2k4X3bC8gD2IhYt301UAgb/Og2L2LjKZC1QkdaZ8PQQDYIe8QA== X-Received: by 2002:a17:902:db0a:b0:1e2:1db3:ebeb with SMTP id m10-20020a170902db0a00b001e21db3ebebmr3985587plx.57.1713447891167; Thu, 18 Apr 2024 06:44:51 -0700 (PDT) Received: from LancedeMBP.lan ([112.10.225.217]) by smtp.gmail.com with ESMTPSA id d8-20020a170902b70800b001e4fdcf67desm1504837pls.299.2024.04.18.06.44.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Apr 2024 06:44:50 -0700 (PDT) From: Lance Yang To: akpm@linux-foundation.org Cc: ryan.roberts@arm.com, david@redhat.com, 21cnbao@gmail.com, mhocko@suse.com, fengwei.yin@intel.com, zokeefe@google.com, shy828301@gmail.com, xiehuan09@gmail.com, wangkefeng.wang@huawei.com, songmuchun@bytedance.com, peterx@redhat.com, minchan@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Lance Yang Subject: [PATCH v10 2/4] mm/arm64: override clear_young_dirty_ptes() batch helper Date: Thu, 18 Apr 2024 21:44:33 +0800 Message-Id: <20240418134435.6092-3-ioworker0@gmail.com> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20240418134435.6092-1-ioworker0@gmail.com> References: <20240418134435.6092-1-ioworker0@gmail.com> 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" The per-pte get_and_clear/modify/set approach would result in unfolding/refolding for contpte mappings on arm64. So we need to override clear_young_dirty_ptes() for arm64 to avoid it. Suggested-by: Barry Song <21cnbao@gmail.com> Suggested-by: Ryan Roberts Reviewed-by: Ryan Roberts Signed-off-by: Lance Yang --- arch/arm64/include/asm/pgtable.h | 55 ++++++++++++++++++++++++++++++++ arch/arm64/mm/contpte.c | 29 +++++++++++++++++ 2 files changed, 84 insertions(+) diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgta= ble.h index 9fd8613b2db2..1303d30287dc 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -1223,6 +1223,46 @@ static inline void __wrprotect_ptes(struct mm_struct= *mm, unsigned long address, __ptep_set_wrprotect(mm, address, ptep); } =20 +static inline void __clear_young_dirty_pte(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, + pte_t pte, cydp_t flags) +{ + pte_t old_pte; + + do { + old_pte =3D pte; + + if (flags & CYDP_CLEAR_YOUNG) + pte =3D pte_mkold(pte); + if (flags & CYDP_CLEAR_DIRTY) + pte =3D pte_mkclean(pte); + + pte_val(pte) =3D cmpxchg_relaxed(&pte_val(*ptep), + pte_val(old_pte), pte_val(pte)); + } while (pte_val(pte) !=3D pte_val(old_pte)); +} + +static inline void __clear_young_dirty_ptes(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, + unsigned int nr, cydp_t flags) +{ + pte_t pte; + + for (;;) { + pte =3D __ptep_get(ptep); + + if (flags =3D=3D (CYDP_CLEAR_YOUNG | CYDP_CLEAR_DIRTY)) + __set_pte(ptep, pte_mkclean(pte_mkold(pte))); + else + __clear_young_dirty_pte(vma, addr, ptep, pte, flags); + + if (--nr =3D=3D 0) + break; + ptep++; + addr +=3D PAGE_SIZE; + } +} + #ifdef CONFIG_TRANSPARENT_HUGEPAGE #define __HAVE_ARCH_PMDP_SET_WRPROTECT static inline void pmdp_set_wrprotect(struct mm_struct *mm, @@ -1379,6 +1419,9 @@ extern void contpte_wrprotect_ptes(struct mm_struct *= mm, unsigned long addr, extern int contpte_ptep_set_access_flags(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep, pte_t entry, int dirty); +extern void contpte_clear_young_dirty_ptes(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, + unsigned int nr, cydp_t flags); =20 static __always_inline void contpte_try_fold(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pte) @@ -1603,6 +1646,17 @@ static inline int ptep_set_access_flags(struct vm_ar= ea_struct *vma, return contpte_ptep_set_access_flags(vma, addr, ptep, entry, dirty); } =20 +#define clear_young_dirty_ptes clear_young_dirty_ptes +static inline void clear_young_dirty_ptes(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, + unsigned int nr, cydp_t flags) +{ + if (likely(nr =3D=3D 1 && !pte_cont(__ptep_get(ptep)))) + __clear_young_dirty_ptes(vma, addr, ptep, nr, flags); + else + contpte_clear_young_dirty_ptes(vma, addr, ptep, nr, flags); +} + #else /* CONFIG_ARM64_CONTPTE */ =20 #define ptep_get __ptep_get @@ -1622,6 +1676,7 @@ static inline int ptep_set_access_flags(struct vm_are= a_struct *vma, #define wrprotect_ptes __wrprotect_ptes #define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS #define ptep_set_access_flags __ptep_set_access_flags +#define clear_young_dirty_ptes __clear_young_dirty_ptes =20 #endif /* CONFIG_ARM64_CONTPTE */ =20 diff --git a/arch/arm64/mm/contpte.c b/arch/arm64/mm/contpte.c index 1b64b4c3f8bf..9f9486de0004 100644 --- a/arch/arm64/mm/contpte.c +++ b/arch/arm64/mm/contpte.c @@ -361,6 +361,35 @@ void contpte_wrprotect_ptes(struct mm_struct *mm, unsi= gned long addr, } EXPORT_SYMBOL_GPL(contpte_wrprotect_ptes); =20 +void contpte_clear_young_dirty_ptes(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, + unsigned int nr, cydp_t flags) +{ + /* + * We can safely clear access/dirty without needing to unfold from + * the architectures perspective, even when contpte is set. If the + * range starts or ends midway through a contpte block, we can just + * expand to include the full contpte block. While this is not + * exactly what the core-mm asked for, it tracks access/dirty per + * folio, not per page. And since we only create a contpte block + * when it is covered by a single folio, we can get away with + * clearing access/dirty for the whole block. + */ + unsigned long start =3D addr; + unsigned long end =3D start + nr; + + 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); + } + + __clear_young_dirty_ptes(vma, start, ptep, end - start, flags); +} +EXPORT_SYMBOL_GPL(contpte_clear_young_dirty_ptes); + int contpte_ptep_set_access_flags(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep, pte_t entry, int dirty) --=20 2.33.1