From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8B42CF506CB for ; Mon, 16 Mar 2026 13:09:12 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id F23AC6B0266; Mon, 16 Mar 2026 09:09:11 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id EA3C26B026A; Mon, 16 Mar 2026 09:09:11 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D51F96B026B; Mon, 16 Mar 2026 09:09:11 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id BBA3D6B0266 for ; Mon, 16 Mar 2026 09:09:11 -0400 (EDT) Received: from smtpin28.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 6F40B892F7 for ; Mon, 16 Mar 2026 13:09:11 +0000 (UTC) X-FDA: 84551956902.28.CED3E8F Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf24.hostedemail.com (Postfix) with ESMTP id B222E18000A for ; Mon, 16 Mar 2026 13:09:09 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=jMFk18sm; spf=pass (imf24.hostedemail.com: domain of ljs@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=ljs@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1773666549; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=2qNTRboQnFOzEcDZWjE5gbTfa/sTE7nhGfdbNQAdviM=; b=xUmL0CkKjjXOOy/NWad42Kcq3oI52RztQMzSxclz150/mwGtdkGCBYPndebsEsu2XRB3C9 5U0lvZKwjQNfxlgdZUw/57+WyzBZlznHE1Q2zgvsVTuNE/F12+dtABZ/NPsP+TPIY1i93e CsunDEeqlUEpjf/VOCuVu4fwxwGm5dM= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1773666549; a=rsa-sha256; cv=none; b=5i9YOtfDUfVgTQ/nulYBPezojtzqoyKzrWnZd91A+6cEyZ7lu2KqwLpWq+EGtMhTpMsfpv 26/xLOEaosduGq9zofz4aOU88kdfYlXOOHrq4jOmWiezTgHsrUmBK/uHrw23UlbH5rEUGq teISWANO+PN+Aar8UVgsJgBabEKVk/Q= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=jMFk18sm; spf=pass (imf24.hostedemail.com: domain of ljs@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=ljs@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id C2D6240E2A; Mon, 16 Mar 2026 13:09:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 08F7CC19421; Mon, 16 Mar 2026 13:09:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773666548; bh=dFX8i/GTSiNIxM80Lt/6wl8nx+eQNgs3hUpoH1nEJn0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jMFk18smoAUK8/iQkecF/D+k4Fm8bjm4Y62bOngadQJFJO1eJVtoUoR5yvb3TpnvH ItcJfNDFkaS1hwr4umR0dz77y2yJonPNOkkbygIC+3M31JRdxx3KLCvdl3UDA/zZ6K L+0cwUopOhiHs4KgH7ynZ8pIwu1Tp3n8f32OxxH7D7bd8n8pwBMzux42iD1c1g0IS4 uV6AtCA6ZBPSvitBDr2wuTXw9nkPvQbhj5g2jSmtki81HIxoFhtbkfIqpdmkHCWhpS AGs8UgsjIrqKTJRrPvT1zGlgYCd0YWmkxw2g4T75jcce9dXreobooxdi2hl2Y/gEKb 0AtmwCo/kr82Q== From: "Lorenzo Stoakes (Oracle)" To: Andrew Morton Cc: David Hildenbrand , "Liam R . Howlett" , Vlastimil Babka , Jann Horn , Pedro Falcato , Mike Rapoport , Suren Baghdasaryan , Kees Cook , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Vineet Gupta , Russell King , Catalin Marinas , Will Deacon , Brian Cain , Huacai Chen , WANG Xuerui , Thomas Bogendoerfer , Dinh Nguyen , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . Peter Anvin" , Richard Weinberger , Anton Ivanov , Johannes Berg , Alexander Viro , Christian Brauner , Jan Kara , Xu Xin , Chengming Zhou , Michal Hocko , Paul Moore , Stephen Smalley , Ondrej Mosnacek , linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-hexagon@vger.kernel.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-um@lists.infradead.org, linux-fsdevel@vger.kernel.org, selinux@vger.kernel.org Subject: [PATCH v2 05/23] mm/vma: use new VMA flags for sticky flags logic Date: Mon, 16 Mar 2026 13:07:54 +0000 Message-ID: <005cac3e37830a33f473edc780a5dae5e00a3845.1773665966.git.ljs@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: B222E18000A X-Stat-Signature: cognquq1y88ocqj17n1xhpn4bn1pcfhn X-Rspam-User: X-HE-Tag: 1773666549-323818 X-HE-Meta: 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 dfVbaxFt twbbv6dyYHxHEc9qfM4rMr9u5ivo0E9v6wlazlArtr6ifL7i5hDzQdUQ158W6DqgVtgO21icTNx6J4F/O172avb/EKFXTMYbgCE0xytcP3vvhNAc0lsBlE9uZiAHf1qm2Oe+TCqQsFGVvoaDFKNb4lWWW/U5pUspiiAw04EyjwJCSq8b86RNgiPX+7ZHX2YbIJC6FvPygxtcboTCRP7AAlu7yk/QQtgsfMPB4u/IHNOcvVLUMpMVr5+/AmYOnEqxgp36z7CZk02hqFjbo8SqkOLyt9b4NLBtAj27GlBrVsRzaQI3Jwu6s9yr75g== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Use the new vma_flags_t flags implementation to perform the logic around sticky flags and what flags are ignored on VMA merge. We make use of the new vma_flags_empty(), vma_flags_diff_pair(), and vma_flags_and_mask() functionality. Note that we cannot rely on VM_NONE convenience any longer, so have to explicitly check for cases where VMA flags would not be specified. Also update the VMA tests accordingly. Signed-off-by: Lorenzo Stoakes (Oracle) --- include/linux/mm.h | 32 +++++++++++--------- mm/vma.c | 47 ++++++++++++++++++++++-------- tools/testing/vma/include/custom.h | 5 ---- tools/testing/vma/include/dup.h | 9 ++++-- 4 files changed, 61 insertions(+), 32 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 6d2c4bd2c61d..b75e089dfd65 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -540,6 +540,7 @@ enum { /* VMA basic access permission flags */ #define VM_ACCESS_FLAGS (VM_READ | VM_WRITE | VM_EXEC) +#define VMA_ACCESS_FLAGS mk_vma_flags(VMA_READ_BIT, VMA_WRITE_BIT, VMA_EXEC_BIT) /* * Special vmas that are non-mergable, non-mlock()able. @@ -585,27 +586,32 @@ enum { * possesses it but the other does not, the merged VMA should nonetheless have * applied to it: * - * VM_SOFTDIRTY - if a VMA is marked soft-dirty, that is has not had its - * references cleared via /proc/$pid/clear_refs, any merged VMA - * should be considered soft-dirty also as it operates at a VMA - * granularity. + * VMA_SOFTDIRTY_BIT - if a VMA is marked soft-dirty, that is has not had its + * references cleared via /proc/$pid/clear_refs, any + * merged VMA should be considered soft-dirty also as it + * operates at a VMA granularity. * - * VM_MAYBE_GUARD - If a VMA may have guard regions in place it implies that - * mapped page tables may contain metadata not described by the - * VMA and thus any merged VMA may also contain this metadata, - * and thus we must make this flag sticky. + * VMA_MAYBE_GUARD_BIT - If a VMA may have guard regions in place it implies + * that mapped page tables may contain metadata not + * described by the VMA and thus any merged VMA may also + * contain this metadata, and thus we must make this flag + * sticky. */ -#define VM_STICKY (VM_SOFTDIRTY | VM_MAYBE_GUARD) +#ifdef CONFIG_MEM_SOFT_DIRTY +#define VMA_STICKY_FLAGS mk_vma_flags(VMA_SOFTDIRTY_BIT, VMA_MAYBE_GUARD_BIT) +#else +#define VMA_STICKY_FLAGS mk_vma_flags(VMA_MAYBE_GUARD_BIT) +#endif /* * VMA flags we ignore for the purposes of merge, i.e. one VMA possessing one * of these flags and the other not does not preclude a merge. * - * VM_STICKY - When merging VMAs, VMA flags must match, unless they are - * 'sticky'. If any sticky flags exist in either VMA, we simply - * set all of them on the merged VMA. + * VMA_STICKY_FLAGS - When merging VMAs, VMA flags must match, unless they + * are 'sticky'. If any sticky flags exist in either VMA, + * we simply set all of them on the merged VMA. */ -#define VM_IGNORE_MERGE VM_STICKY +#define VMA_IGNORE_MERGE_FLAGS VMA_STICKY_FLAGS /* * Flags which should result in page tables being copied on fork. These are diff --git a/mm/vma.c b/mm/vma.c index 4d21e7d8e93c..15d643eee97f 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -86,10 +86,15 @@ static bool vma_is_fork_child(struct vm_area_struct *vma) static inline bool is_mergeable_vma(struct vma_merge_struct *vmg, bool merge_next) { struct vm_area_struct *vma = merge_next ? vmg->next : vmg->prev; + vma_flags_t diff; if (!mpol_equal(vmg->policy, vma_policy(vma))) return false; - if ((vma->vm_flags ^ vmg->vm_flags) & ~VM_IGNORE_MERGE) + + diff = vma_flags_diff_pair(&vma->flags, &vmg->vma_flags); + vma_flags_clear_mask(&diff, VMA_IGNORE_MERGE_FLAGS); + + if (!vma_flags_empty(&diff)) return false; if (vma->vm_file != vmg->file) return false; @@ -805,7 +810,8 @@ static bool can_merge_remove_vma(struct vm_area_struct *vma) static __must_check struct vm_area_struct *vma_merge_existing_range( struct vma_merge_struct *vmg) { - vm_flags_t sticky_flags = vmg->vm_flags & VM_STICKY; + vma_flags_t sticky_flags = vma_flags_and_mask(&vmg->vma_flags, + VMA_STICKY_FLAGS); struct vm_area_struct *middle = vmg->middle; struct vm_area_struct *prev = vmg->prev; struct vm_area_struct *next; @@ -898,15 +904,21 @@ static __must_check struct vm_area_struct *vma_merge_existing_range( vma_start_write(middle); if (merge_right) { + const vma_flags_t next_sticky = + vma_flags_and_mask(&next->flags, VMA_STICKY_FLAGS); + vma_start_write(next); vmg->target = next; - sticky_flags |= (next->vm_flags & VM_STICKY); + vma_flags_set_mask(&sticky_flags, next_sticky); } if (merge_left) { + const vma_flags_t prev_sticky = + vma_flags_and_mask(&prev->flags, VMA_STICKY_FLAGS); + vma_start_write(prev); vmg->target = prev; - sticky_flags |= (prev->vm_flags & VM_STICKY); + vma_flags_set_mask(&sticky_flags, prev_sticky); } if (merge_both) { @@ -976,7 +988,7 @@ static __must_check struct vm_area_struct *vma_merge_existing_range( if (err || commit_merge(vmg)) goto abort; - vm_flags_set(vmg->target, sticky_flags); + vma_set_flags_mask(vmg->target, sticky_flags); khugepaged_enter_vma(vmg->target, vmg->vm_flags); vmg->state = VMA_MERGE_SUCCESS; return vmg->target; @@ -1154,7 +1166,10 @@ int vma_expand(struct vma_merge_struct *vmg) struct vm_area_struct *target = vmg->target; struct vm_area_struct *next = vmg->next; bool remove_next = false; - vm_flags_t sticky_flags; + vma_flags_t sticky_flags = + vma_flags_and_mask(&vmg->vma_flags, VMA_STICKY_FLAGS); + const vma_flags_t target_sticky = + vma_flags_and_mask(&target->flags, VMA_STICKY_FLAGS); int ret = 0; mmap_assert_write_locked(vmg->mm); @@ -1174,10 +1189,13 @@ int vma_expand(struct vma_merge_struct *vmg) VM_WARN_ON_VMG(target->vm_start < vmg->start || target->vm_end > vmg->end, vmg); - sticky_flags = vmg->vm_flags & VM_STICKY; - sticky_flags |= target->vm_flags & VM_STICKY; - if (remove_next) - sticky_flags |= next->vm_flags & VM_STICKY; + vma_flags_set_mask(&sticky_flags, target_sticky); + if (remove_next) { + const vma_flags_t next_sticky = + vma_flags_and_mask(&next->flags, VMA_STICKY_FLAGS); + + vma_flags_set_mask(&sticky_flags, next_sticky); + } /* * If we are removing the next VMA or copying from a VMA @@ -1200,7 +1218,7 @@ int vma_expand(struct vma_merge_struct *vmg) if (commit_merge(vmg)) goto nomem; - vm_flags_set(target, sticky_flags); + vma_set_flags_mask(target, sticky_flags); return 0; nomem: @@ -1950,10 +1968,15 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, */ static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b) { + vma_flags_t diff = vma_flags_diff_pair(&a->flags, &b->flags); + + vma_flags_clear_mask(&diff, VMA_ACCESS_FLAGS); + vma_flags_clear_mask(&diff, VMA_IGNORE_MERGE_FLAGS); + return a->vm_end == b->vm_start && mpol_equal(vma_policy(a), vma_policy(b)) && a->vm_file == b->vm_file && - !((a->vm_flags ^ b->vm_flags) & ~(VM_ACCESS_FLAGS | VM_IGNORE_MERGE)) && + vma_flags_empty(&diff) && b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT); } diff --git a/tools/testing/vma/include/custom.h b/tools/testing/vma/include/custom.h index 6200f938e586..7cdd0f60600a 100644 --- a/tools/testing/vma/include/custom.h +++ b/tools/testing/vma/include/custom.h @@ -134,8 +134,3 @@ static __always_inline bool vma_flags_same_mask(vma_flags_t *flags, vma_flags_same_mask(flags, mk_vma_flags(__VA_ARGS__)) #define VMA_SPECIAL_FLAGS mk_vma_flags(VMA_IO_BIT, VMA_DONTEXPAND_BIT, \ VMA_PFNMAP_BIT, VMA_MIXEDMAP_BIT) -#ifdef CONFIG_MEM_SOFT_DIRTY -#define VMA_STICKY_FLAGS mk_vma_flags(VMA_SOFTDIRTY_BIT, VMA_MAYBE_GUARD_BIT) -#else -#define VMA_STICKY_FLAGS mk_vma_flags(VMA_MAYBE_GUARD_BIT) -#endif diff --git a/tools/testing/vma/include/dup.h b/tools/testing/vma/include/dup.h index 44f77453ee85..e5fdf6f5a033 100644 --- a/tools/testing/vma/include/dup.h +++ b/tools/testing/vma/include/dup.h @@ -338,6 +338,7 @@ enum { /* VMA basic access permission flags */ #define VM_ACCESS_FLAGS (VM_READ | VM_WRITE | VM_EXEC) +#define VMA_ACCESS_FLAGS mk_vma_flags(VMA_READ_BIT, VMA_WRITE_BIT, VMA_EXEC_BIT) /* * Special vmas that are non-mergable, non-mlock()able. @@ -363,9 +364,13 @@ enum { #define CAP_IPC_LOCK 14 -#define VM_STICKY (VM_SOFTDIRTY | VM_MAYBE_GUARD) +#ifdef CONFIG_MEM_SOFT_DIRTY +#define VMA_STICKY_FLAGS mk_vma_flags(VMA_SOFTDIRTY_BIT, VMA_MAYBE_GUARD_BIT) +#else +#define VMA_STICKY_FLAGS mk_vma_flags(VMA_MAYBE_GUARD_BIT) +#endif -#define VM_IGNORE_MERGE VM_STICKY +#define VMA_IGNORE_MERGE_FLAGS VMA_STICKY_FLAGS #define VM_COPY_ON_FORK (VM_PFNMAP | VM_MIXEDMAP | VM_UFFD_WP | VM_MAYBE_GUARD) -- 2.53.0