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Wed, 25 Feb 2026 22:22:42 -0500 X-MC-Unique: MzsV8NQpOmOXOQsqWwBWTg-1 X-Mimecast-MFC-AGG-ID: MzsV8NQpOmOXOQsqWwBWTg_1772076154 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 1F27218028AC; Thu, 26 Feb 2026 03:22:32 +0000 (UTC) Received: from h1.redhat.com (unknown [10.22.64.173]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 612E83003DA1; Thu, 26 Feb 2026 03:22:20 +0000 (UTC) From: Nico Pache To: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org Cc: aarcange@redhat.com, akpm@linux-foundation.org, anshuman.khandual@arm.com, apopple@nvidia.com, baohua@kernel.org, baolin.wang@linux.alibaba.com, byungchul@sk.com, catalin.marinas@arm.com, cl@gentwo.org, corbet@lwn.net, dave.hansen@linux.intel.com, david@kernel.org, dev.jain@arm.com, gourry@gourry.net, hannes@cmpxchg.org, hughd@google.com, jack@suse.cz, jackmanb@google.com, jannh@google.com, jglisse@google.com, joshua.hahnjy@gmail.com, kas@kernel.org, lance.yang@linux.dev, Liam.Howlett@oracle.com, lorenzo.stoakes@oracle.com, mathieu.desnoyers@efficios.com, matthew.brost@intel.com, mhiramat@kernel.org, mhocko@suse.com, npache@redhat.com, peterx@redhat.com, pfalcato@suse.de, rakie.kim@sk.com, raquini@redhat.com, rdunlap@infradead.org, richard.weiyang@gmail.com, rientjes@google.com, rostedt@goodmis.org, rppt@kernel.org, ryan.roberts@arm.com, shivankg@amd.com, sunnanyong@huawei.com, surenb@google.com, thomas.hellstrom@linux.intel.com, tiwai@suse.de, usamaarif642@gmail.com, vbabka@suse.cz, vishal.moola@gmail.com, wangkefeng.wang@huawei.com, will@kernel.org, willy@infradead.org, yang@os.amperecomputing.com, ying.huang@linux.alibaba.com, ziy@nvidia.com, zokeefe@google.com Subject: [PATCH mm-unstable v15 01/13] mm/khugepaged: generalize hugepage_vma_revalidate for mTHP support Date: Wed, 25 Feb 2026 20:22:17 -0700 Message-ID: <20260226032217.232353-1-npache@redhat.com> In-Reply-To: <20260226031741.230674-1-npache@redhat.com> References: <20260226031741.230674-1-npache@redhat.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 X-Mimecast-MFC-PROC-ID: XM6jy3Mk6AIkRtMXkqbatklA88KqGJbct8szMIprHTM_1772076154 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit content-type: text/plain; charset="US-ASCII"; x-default=true For khugepaged to support different mTHP orders, we must generalize this to check if the PMD is not shared by another VMA and that the order is enabled. No functional change in this patch. Also correct a comment about the functionality of the revalidation. Reviewed-by: Wei Yang Reviewed-by: Lance Yang Reviewed-by: Baolin Wang Reviewed-by: Lorenzo Stoakes Reviewed-by: Zi Yan Co-developed-by: Dev Jain Signed-off-by: Dev Jain Signed-off-by: Nico Pache --- mm/khugepaged.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 0058970d4579..c7f2c4a90910 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -895,12 +895,13 @@ static int collapse_find_target_node(struct collapse_control *cc) /* * If mmap_lock temporarily dropped, revalidate vma - * before taking mmap_lock. + * after taking the mmap_lock again. * Returns enum scan_result value. */ static enum scan_result hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address, - bool expect_anon, struct vm_area_struct **vmap, struct collapse_control *cc) + bool expect_anon, struct vm_area_struct **vmap, + struct collapse_control *cc, unsigned int order) { struct vm_area_struct *vma; enum tva_type type = cc->is_khugepaged ? TVA_KHUGEPAGED : @@ -913,15 +914,16 @@ static enum scan_result hugepage_vma_revalidate(struct mm_struct *mm, unsigned l if (!vma) return SCAN_VMA_NULL; + /* Always check the PMD order to ensure its not shared by another VMA */ if (!thp_vma_suitable_order(vma, address, PMD_ORDER)) return SCAN_ADDRESS_RANGE; - if (!thp_vma_allowable_order(vma, vma->vm_flags, type, PMD_ORDER)) + if (!thp_vma_allowable_orders(vma, vma->vm_flags, type, BIT(order))) return SCAN_VMA_CHECK; /* * Anon VMA expected, the address may be unmapped then * remapped to file after khugepaged reaquired the mmap_lock. * - * thp_vma_allowable_order may return true for qualified file + * thp_vma_allowable_orders may return true for qualified file * vmas. */ if (expect_anon && (!(*vmap)->anon_vma || !vma_is_anonymous(*vmap))) @@ -1114,7 +1116,8 @@ static enum scan_result collapse_huge_page(struct mm_struct *mm, unsigned long a goto out_nolock; mmap_read_lock(mm); - result = hugepage_vma_revalidate(mm, address, true, &vma, cc); + result = hugepage_vma_revalidate(mm, address, true, &vma, cc, + HPAGE_PMD_ORDER); if (result != SCAN_SUCCEED) { mmap_read_unlock(mm); goto out_nolock; @@ -1148,7 +1151,8 @@ static enum scan_result collapse_huge_page(struct mm_struct *mm, unsigned long a * mmap_lock. */ mmap_write_lock(mm); - result = hugepage_vma_revalidate(mm, address, true, &vma, cc); + result = hugepage_vma_revalidate(mm, address, true, &vma, cc, + HPAGE_PMD_ORDER); if (result != SCAN_SUCCEED) goto out_up_write; /* check if the pmd is still valid */ @@ -2863,7 +2867,7 @@ int madvise_collapse(struct vm_area_struct *vma, unsigned long start, mmap_locked = true; *lock_dropped = true; result = hugepage_vma_revalidate(mm, addr, false, &vma, - cc); + cc, HPAGE_PMD_ORDER); if (result != SCAN_SUCCEED) { last_fail = result; goto out_nolock; -- 2.53.0