From nobody Mon Feb 9 23:04:39 2026 Received: from mail-pf1-f176.google.com (mail-pf1-f176.google.com [209.85.210.176]) (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 49D3F283FFC for ; Mon, 20 Oct 2025 03:11:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.176 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760929894; cv=none; b=Kxfj3LG4jdAZLnXfTxHyEYQtEJCzZZBG8NAjhVimaOHslYKGD9EAMeToSuwZVN/ny16nf6mA3T7/egtSR0fP2jmRvqi6wchzHfXh+WcaYN1w4jb++py39cfrT5dG7XVTg7gX6MvBh0SAmDlRJ5EXAiMElMrF8Cxr/iyef0JuqZk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760929894; c=relaxed/simple; bh=ru445dP8wX8xeVS/YTFwgQYUgOJSqNCeWR/H8JIL3F0=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=tGEEDo3uzlZGhCMFaCSAborGg7gsoftvez1Y5qHWjz9R7Y3O1I+nDHu8eu+oNm7o5BhdQ6J1GOtHDOaGf54cRqbaPlaN6pFlajI3qpQZ/AoX2bRwXlCjIoVeOqXs9e+FmpB+zFxlp/YQLqt0AGumAy2sLcliVHDhojZTr0X2feY= 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=XJR94W4W; arc=none smtp.client-ip=209.85.210.176 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="XJR94W4W" Received: by mail-pf1-f176.google.com with SMTP id d2e1a72fcca58-781001e3846so3613166b3a.2 for ; Sun, 19 Oct 2025 20:11:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1760929892; x=1761534692; 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=DcLsfJON0lJjNOupQsAXtJtd7DDEJTZNiP6jZEns7kk=; b=XJR94W4WvtxsAPA3JI7hKBHjmaqLhzzpBXswW0ms1NSSVkgOpWMsmISBjbV9+aI3K8 UD5A5PoHrrOKyH+SIMRZq40kFhAIlFHecsX7hPfpQXyo1//bAlD/z/z6iFI1kyb6f7oi t+lydhgMgVwB25xaaVGrl6c1Y147mfFXgtVvsARqhHDuzHxu29tikus2BdsUZWeqd4vO fC8yKSU1aaI0zigh9nBliH96FXZ/NrAJzzQ1SF4dChPCsI3oz/uL77TGXNGtdLvrxlPW IUPFQv5nC+n6WdiJAJ+TfWp7rSA010BemowPK75Qm83hFv8zy3kcHrHgBoiYNrTrfLFt zJrA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1760929892; x=1761534692; 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=DcLsfJON0lJjNOupQsAXtJtd7DDEJTZNiP6jZEns7kk=; b=WTNLrHRa0lwgRBpAP7G2Jyki33D9DCto2VqPIQXIO/U+Zra3EcXUT+P43Q9/nPpPYs V0EpIjFcIFhOSE0PdqidTHoF+e367HVaFCbrF5pHm5lHHjh4OdclfEdI4O38MbKy6Lef ovRPPsXscHCNVRC4BDDoYsXF0zM0iWQIDUuvgpP4lNV+eHGakkePAax9rpNY4QBzITAg 3J29JFclwBkmVfZQc9tKlaYR+D1qWJk4Z+AWxsclBslYyKfnwCY6nt8Yse0lKuqGe8Xh SqpVNsjJu3m0zwQTlOKrbpYheo7Y6CQ9xN+MVOEyZCEGl+fOeOL+pvCfTybeM/aCdu1r Oobw== X-Forwarded-Encrypted: i=1; AJvYcCXZeywTrg3Sc8LQIKjzPI55maZIB3497eKgTiktEbKjMVq5CAhihyPq9u0UrWC8linkV/MV/WgjHN5PKf8=@vger.kernel.org X-Gm-Message-State: AOJu0YzYGt4UIdDVviigpHmt9YHcUVXFaPgj0/JAsdmrNP7ZJRwLAUGj wle/I6dz7LYqN/r09/7uJm2ny7vvTfAzcenDdBiwPpk3LdCMx1nmSc3s X-Gm-Gg: ASbGncvSrJTJuzqFpEEGMLUH1arEMUuclpLY+0FGzSiQiZT/UG6UwGbKFCxxU3610KR LDRJ+8YIxW+XHxyYC7YV3t37dMSDOLaETyNqw/tRY+1zldfvd976unI3JZzVBrflyIXzY2rmU3Q RYDaYllyc7gk06jZSBci2VDr9Tp/lW51v0YeseNYQW54sqT7jGgqpi5w+Yt6ITljfIcctdy5ifB bZufOk+dB172Gi7e18Bk3rPYFUsRVFXCYzafGFKbItQ3EoDUgDVaud1OLS89wrFBBIr1KIHvc+L p1VDOn/Apgw7am9xmJUWHIRSz6HpMSxMDkPCSrq3ksQtWS2myRjrnn+ra5rf5VuVAHvVPsPHW8/ WNpATymN8AtiMfjkuTNPwts/wOMUFdJT1wYQNb3rmQljWw8FwM49y6cJVfns0cpYIvfnClxXF8+ rr2uT9yBa+ezzhH6ObJjeFVUh+oZjio0vAnf0GqE1I X-Google-Smtp-Source: AGHT+IFMHeuB2yTajHJ8tS5j2zdt34EIEn0u6ljuSzQNjGyzEgX3fDhahWmDGqGBC5JB3iyfLxZ55g== X-Received: by 2002:a17:903:4405:b0:27e:ec72:f50 with SMTP id d9443c01a7336-290cba419bemr101429775ad.51.1760929892428; Sun, 19 Oct 2025 20:11:32 -0700 (PDT) Received: from localhost.localdomain ([2409:891f:1da1:a41d:2120:6ebb:ce22:6a12]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-292471d5794sm66007245ad.53.2025.10.19.20.11.23 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Sun, 19 Oct 2025 20:11:32 -0700 (PDT) From: Yafang Shao To: akpm@linux-foundation.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, david@redhat.com, ziy@nvidia.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, hannes@cmpxchg.org, usamaarif642@gmail.com, gutierrez.asier@huawei-partners.com, willy@infradead.org, ameryhung@gmail.com, rientjes@google.com, corbet@lwn.net, 21cnbao@gmail.com, shakeel.butt@linux.dev, tj@kernel.org, lance.yang@linux.dev, rdunlap@infradead.org Cc: bpf@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Yafang Shao , Yang Shi Subject: [PATCH v11 mm-new 01/10] mm: thp: remove vm_flags parameter from khugepaged_enter_vma() Date: Mon, 20 Oct 2025 11:10:51 +0800 Message-Id: <20251020031100.49917-2-laoar.shao@gmail.com> X-Mailer: git-send-email 2.37.1 (Apple Git-137.1) In-Reply-To: <20251020031100.49917-1-laoar.shao@gmail.com> References: <20251020031100.49917-1-laoar.shao@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 khugepaged_enter_vma() function requires handling in two specific scenarios: 1. New VMA creation When a new VMA is created (for anon vma, it is deferred to pagefault), if vma->vm_mm is not present in khugepaged_mm_slot, it must be added. In this case, khugepaged_enter_vma() is called after vma->vm_flags have been set, allowing direct use of the VMA's flags. 2. VMA flag modification When vma->vm_flags are modified (particularly when VM_HUGEPAGE is set), the system must recheck whether to add vma->vm_mm to khugepaged_mm_slot. Currently, khugepaged_enter_vma() is called before the flag update, so the call must be relocated to occur after vma->vm_flags have been set. In the VMA merging path, khugepaged_enter_vma() is also called. For this case, since VMA merging only occurs when the vm_flags of both VMAs are identical (excluding special flags like VM_SOFTDIRTY), we can safely use target->vm_flags instead. (It is worth noting that khugepaged_enter_vma() can be removed from the VMA merging path because the VMA has already been added in the two aforementioned cases. We will address this cleanup in a separate patch.) After this change, we can further remove vm_flags parameter from thp_vma_allowable_order(). That will be handled in a followup patch. Signed-off-by: Yafang Shao Cc: Yang Shi Cc: Usama Arif --- include/linux/khugepaged.h | 10 ++++++---- mm/huge_memory.c | 2 +- mm/khugepaged.c | 27 ++++++++++++++------------- mm/madvise.c | 7 +++++++ mm/vma.c | 6 +++--- 5 files changed, 31 insertions(+), 21 deletions(-) diff --git a/include/linux/khugepaged.h b/include/linux/khugepaged.h index eb1946a70cff..b30814d3d665 100644 --- a/include/linux/khugepaged.h +++ b/include/linux/khugepaged.h @@ -13,8 +13,8 @@ extern void khugepaged_destroy(void); extern int start_stop_khugepaged(void); extern void __khugepaged_enter(struct mm_struct *mm); extern void __khugepaged_exit(struct mm_struct *mm); -extern void khugepaged_enter_vma(struct vm_area_struct *vma, - vm_flags_t vm_flags); +extern void khugepaged_enter_vma(struct vm_area_struct *vma); +extern void khugepaged_enter_mm(struct mm_struct *mm); extern void khugepaged_min_free_kbytes_update(void); extern bool current_is_khugepaged(void); extern int collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long add= r, @@ -38,8 +38,10 @@ static inline void khugepaged_fork(struct mm_struct *mm,= struct mm_struct *oldmm static inline void khugepaged_exit(struct mm_struct *mm) { } -static inline void khugepaged_enter_vma(struct vm_area_struct *vma, - vm_flags_t vm_flags) +static inline void khugepaged_enter_vma(struct vm_area_struct *vma) +{ +} +static inline void khugepaged_enter_mm(struct mm_struct *mm) { } static inline int collapse_pte_mapped_thp(struct mm_struct *mm, diff --git a/mm/huge_memory.c b/mm/huge_memory.c index bfb52c564fb3..ea3199ea98fc 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1390,7 +1390,7 @@ vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault= *vmf) ret =3D vmf_anon_prepare(vmf); if (ret) return ret; - khugepaged_enter_vma(vma, vma->vm_flags); + khugepaged_enter_vma(vma); =20 if (!(vmf->flags & FAULT_FLAG_WRITE) && !mm_forbids_zeropage(vma->vm_mm) && diff --git a/mm/khugepaged.c b/mm/khugepaged.c index e947b96e1443..c2c683f11251 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -353,12 +353,6 @@ int hugepage_madvise(struct vm_area_struct *vma, #endif *vm_flags &=3D ~VM_NOHUGEPAGE; *vm_flags |=3D VM_HUGEPAGE; - /* - * If the vma become good for khugepaged to scan, - * register it here without waiting a page fault that - * may not happen any time soon. - */ - khugepaged_enter_vma(vma, *vm_flags); break; case MADV_NOHUGEPAGE: *vm_flags &=3D ~VM_HUGEPAGE; @@ -457,14 +451,21 @@ void __khugepaged_enter(struct mm_struct *mm) wake_up_interruptible(&khugepaged_wait); } =20 -void khugepaged_enter_vma(struct vm_area_struct *vma, - vm_flags_t vm_flags) +void khugepaged_enter_mm(struct mm_struct *mm) { - if (!mm_flags_test(MMF_VM_HUGEPAGE, vma->vm_mm) && - hugepage_pmd_enabled()) { - if (thp_vma_allowable_order(vma, vm_flags, TVA_KHUGEPAGED, PMD_ORDER)) - __khugepaged_enter(vma->vm_mm); - } + if (mm_flags_test(MMF_VM_HUGEPAGE, mm)) + return; + if (!hugepage_pmd_enabled()) + return; + + __khugepaged_enter(mm); +} + +void khugepaged_enter_vma(struct vm_area_struct *vma) +{ + if (!thp_vma_allowable_order(vma, vma->vm_flags, TVA_KHUGEPAGED, PMD_ORDE= R)) + return; + khugepaged_enter_mm(vma->vm_mm); } =20 void __khugepaged_exit(struct mm_struct *mm) diff --git a/mm/madvise.c b/mm/madvise.c index fb1c86e630b6..8de7c39305dd 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -1425,6 +1425,13 @@ static int madvise_vma_behavior(struct madvise_behav= ior *madv_behavior) VM_WARN_ON_ONCE(madv_behavior->lock_mode !=3D MADVISE_MMAP_WRITE_LOCK); =20 error =3D madvise_update_vma(new_flags, madv_behavior); + /* + * If the vma become good for khugepaged to scan, + * register it here without waiting a page fault that + * may not happen any time soon. + */ + if (!error && new_flags & VM_HUGEPAGE) + khugepaged_enter_mm(vma->vm_mm); out: /* * madvise() returns EAGAIN if kernel resources, such as diff --git a/mm/vma.c b/mm/vma.c index a2e1ae954662..64bf384fc325 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -973,7 +973,7 @@ static __must_check struct vm_area_struct *vma_merge_ex= isting_range( if (err || commit_merge(vmg)) goto abort; =20 - khugepaged_enter_vma(vmg->target, vmg->vm_flags); + khugepaged_enter_vma(vmg->target); vmg->state =3D VMA_MERGE_SUCCESS; return vmg->target; =20 @@ -1093,7 +1093,7 @@ struct vm_area_struct *vma_merge_new_range(struct vma= _merge_struct *vmg) * following VMA if we have VMAs on both sides. */ if (vmg->target && !vma_expand(vmg)) { - khugepaged_enter_vma(vmg->target, vmg->vm_flags); + khugepaged_enter_vma(vmg->target); vmg->state =3D VMA_MERGE_SUCCESS; return vmg->target; } @@ -2520,7 +2520,7 @@ static int __mmap_new_vma(struct mmap_state *map, str= uct vm_area_struct **vmap) * call covers the non-merge case. */ if (!vma_is_anonymous(vma)) - khugepaged_enter_vma(vma, map->vm_flags); + khugepaged_enter_vma(vma); *vmap =3D vma; return 0; =20 --=20 2.47.3