Patch Detail
get:
Show a patch.
patch:
Update a patch.
put:
Update a patch.
GET /api/patches/2216635/?format=api
{ "id": 2216635, "url": "http://patchwork.ozlabs.org/api/patches/2216635/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linuxppc-dev/patch/20260327021403.214713-3-usama.arif@linux.dev/", "project": { "id": 2, "url": "http://patchwork.ozlabs.org/api/projects/2/?format=api", "name": "Linux PPC development", "link_name": "linuxppc-dev", "list_id": "linuxppc-dev.lists.ozlabs.org", "list_email": "linuxppc-dev@lists.ozlabs.org", "web_url": "https://github.com/linuxppc/wiki/wiki", "scm_url": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git", "webscm_url": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/", "list_archive_url": "https://lore.kernel.org/linuxppc-dev/", "list_archive_url_format": "https://lore.kernel.org/linuxppc-dev/{}/", "commit_url_format": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?id={}" }, "msgid": "<20260327021403.214713-3-usama.arif@linux.dev>", "list_archive_url": "https://lore.kernel.org/linuxppc-dev/20260327021403.214713-3-usama.arif@linux.dev/", "date": "2026-03-27T02:08:44", "name": "[v3,02/24] mm: thp: propagate split failure from vma_adjust_trans_huge()", "commit_ref": null, "pull_url": null, "state": "handled-elsewhere", "archived": false, "hash": "2dfd09e1f141bc4360833b9e7673e6ab46425e7b", "submitter": { "id": 92719, "url": "http://patchwork.ozlabs.org/api/people/92719/?format=api", "name": "Usama Arif", "email": "usama.arif@linux.dev" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/linuxppc-dev/patch/20260327021403.214713-3-usama.arif@linux.dev/mbox/", "series": [ { "id": 497678, "url": "http://patchwork.ozlabs.org/api/series/497678/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=497678", "date": "2026-03-27T02:08:43", "name": "[v3,01/24] mm: thp: make split_huge_pmd functions return int for error propagation", "version": 3, "mbox": "http://patchwork.ozlabs.org/series/497678/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/2216635/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2216635/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "\n <linuxppc-dev+bounces-18845-incoming=patchwork.ozlabs.org@lists.ozlabs.org>", "X-Original-To": [ "incoming@patchwork.ozlabs.org", "linuxppc-dev@lists.ozlabs.org" ], "Delivered-To": "patchwork-incoming@legolas.ozlabs.org", "Authentication-Results": [ "legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256\n header.s=key1 header.b=JXh0qus4;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org\n (client-ip=112.213.38.117; helo=lists.ozlabs.org;\n envelope-from=linuxppc-dev+bounces-18845-incoming=patchwork.ozlabs.org@lists.ozlabs.org;\n receiver=patchwork.ozlabs.org)", "lists.ozlabs.org;\n arc=none smtp.remote-ip=91.218.175.182", "lists.ozlabs.org;\n dmarc=pass (p=none dis=none) header.from=linux.dev", "lists.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256\n header.s=key1 header.b=JXh0qus4;\n\tdkim-atps=neutral", "lists.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=linux.dev\n (client-ip=91.218.175.182; helo=out-182.mta0.migadu.com;\n envelope-from=usama.arif@linux.dev; receiver=lists.ozlabs.org)" ], "Received": [ "from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4fhkk45DJGz1yFp\n\tfor <incoming@patchwork.ozlabs.org>; Fri, 27 Mar 2026 13:14:52 +1100 (AEDT)", "from boromir.ozlabs.org (localhost [127.0.0.1])\n\tby lists.ozlabs.org (Postfix) with ESMTP id 4fhkjt0dVqz2ypm;\n\tFri, 27 Mar 2026 13:14:42 +1100 (AEDT)", "from out-182.mta0.migadu.com (out-182.mta0.migadu.com\n [91.218.175.182])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519 server-signature RSA-PSS (2048 bits) server-digest\n SHA256)\n\t(No client certificate requested)\n\tby lists.ozlabs.org (Postfix) with ESMTPS id 4fhkjr6779z2xR4\n\tfor <linuxppc-dev@lists.ozlabs.org>; Fri, 27 Mar 2026 13:14:40 +1100 (AEDT)" ], "ARC-Seal": "i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1774577681;\n\tcv=none;\n b=Q9jA3ASQa/xTTS3NcGMkOkN5p52dzCmcMSoMCS4/X5EhVgy7KGrzG7XfNlEdxNIBlvJ9T3voWarcQjWARgxMvqo7j9zseowd+Ctb6dRaYHRcg+nHJVy4Ixyz2NM2M+0D/hlI0qEqmYRgtDpjxGmKiRIWIBfYxDiNsFqlBnPjLOiIkzpKUIDlr8iNsK+7Qc+JKwK+bDgGrLcwBNn1LrmgdsGaFbxoMScOamnfqm1wCEE+6hpdWo6WMp57ERsPgY/6kgKcvcsIh0hKh9lBFMhp/4Era1nd+hRNRoNIBEzcubp5uJqTIyaUIdZ1IljLIAj55wy/RY5/3NPgqhGmZ2m/lQ==", "ARC-Message-Signature": "i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707;\n\tt=1774577681; c=relaxed/relaxed;\n\tbh=Q6STvr62iSGyD74aKGWAYxsY9Nv9L3Kw5kG6Q78YS0c=;\n\th=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References:\n\t MIME-Version;\n b=BHChCRNeoSGUj0Fi6lsH5d2lQqLKKhyDhQUv4IGq/o9fyF+rklO48sJZpL1V1fF5pMCpsP1LUDeB9/+OcApUfmM5YezzthnGIsos8w8SYI7ajf7/Luct96AdPrkh2iTgWTHsMSi8a923d4GpUyY09ccfI5Osfm0pxYETWPAplGXJGThfVONIhTDJ5+P2mNrooiT8emZNbMTgetPAk7PNP845V7W+7Ov1cnZFLGuw3PhR7sagtHPqOR6RaFPRLmnGpznMDZEMYZX01sCxRnINaEY+SH2yABFJe0jd8cQyw5u6fCrHNaAhk27wS3XB+eTaTem86EsGClCDvB82Qp0UjA==", "ARC-Authentication-Results": "i=1; lists.ozlabs.org;\n dmarc=pass (p=none dis=none) header.from=linux.dev; dkim=pass (1024-bit key;\n unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256\n header.s=key1 header.b=JXh0qus4; dkim-atps=neutral;\n spf=pass (client-ip=91.218.175.182; helo=out-182.mta0.migadu.com;\n envelope-from=usama.arif@linux.dev;\n receiver=lists.ozlabs.org) smtp.mailfrom=linux.dev", "X-Report-Abuse": "Please report any abuse attempt to abuse@migadu.com and\n include these headers.", "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1;\n\tt=1774577661;\n\th=from:from:reply-to:subject:subject:date:date:message-id:message-id:\n\t to:to:cc:cc:mime-version:mime-version:\n\t content-transfer-encoding:content-transfer-encoding:\n\t in-reply-to:in-reply-to:references:references;\n\tbh=Q6STvr62iSGyD74aKGWAYxsY9Nv9L3Kw5kG6Q78YS0c=;\n\tb=JXh0qus4OUnHnUJQMBwIISIQ03+Y70d5O+Day5tjDbyx3pzwEpYu0lwJjjVphY24TjxxMa\n\t1hFfAyuk5rjIO0pLg3gZ3xFgFBzeuJbGE+WXFJEXpCI6xGIZu5xY6u0fIMlGDpXIyghrV9\n\t9AA/ClvozRfD2U72HJ06fpVqrLPPqR0=", "From": "Usama Arif <usama.arif@linux.dev>", "To": "Andrew Morton <akpm@linux-foundation.org>,\n\tdavid@kernel.org,\n\tLorenzo Stoakes <ljs@kernel.org>,\n\twilly@infradead.org,\n\tlinux-mm@kvack.org", "Cc": "fvdl@google.com,\n\thannes@cmpxchg.org,\n\triel@surriel.com,\n\tshakeel.butt@linux.dev,\n\tkas@kernel.org,\n\tbaohua@kernel.org,\n\tdev.jain@arm.com,\n\tbaolin.wang@linux.alibaba.com,\n\tnpache@redhat.com,\n\tLiam.Howlett@oracle.com,\n\tryan.roberts@arm.com,\n\tVlastimil Babka <vbabka@kernel.org>,\n\tlance.yang@linux.dev,\n\tlinux-kernel@vger.kernel.org,\n\tkernel-team@meta.com,\n\tmaddy@linux.ibm.com,\n\tmpe@ellerman.id.au,\n\tlinuxppc-dev@lists.ozlabs.org,\n\thca@linux.ibm.com,\n\tgor@linux.ibm.com,\n\tagordeev@linux.ibm.com,\n\tborntraeger@linux.ibm.com,\n\tsvens@linux.ibm.com,\n\tlinux-s390@vger.kernel.org,\n\tUsama Arif <usama.arif@linux.dev>", "Subject": "[v3 02/24] mm: thp: propagate split failure from\n vma_adjust_trans_huge()", "Date": "Thu, 26 Mar 2026 19:08:44 -0700", "Message-ID": "<20260327021403.214713-3-usama.arif@linux.dev>", "In-Reply-To": "<20260327021403.214713-1-usama.arif@linux.dev>", "References": "<20260327021403.214713-1-usama.arif@linux.dev>", "X-Mailing-List": "linuxppc-dev@lists.ozlabs.org", "List-Id": "<linuxppc-dev.lists.ozlabs.org>", "List-Help": "<mailto:linuxppc-dev+help@lists.ozlabs.org>", "List-Owner": "<mailto:linuxppc-dev+owner@lists.ozlabs.org>", "List-Post": "<mailto:linuxppc-dev@lists.ozlabs.org>", "List-Archive": "<https://lore.kernel.org/linuxppc-dev/>,\n <https://lists.ozlabs.org/pipermail/linuxppc-dev/>", "List-Subscribe": "<mailto:linuxppc-dev+subscribe@lists.ozlabs.org>,\n <mailto:linuxppc-dev+subscribe-digest@lists.ozlabs.org>,\n <mailto:linuxppc-dev+subscribe-nomail@lists.ozlabs.org>", "List-Unsubscribe": "<mailto:linuxppc-dev+unsubscribe@lists.ozlabs.org>", "Precedence": "list", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "X-Migadu-Flow": "FLOW_OUT", "X-Spam-Status": "No, score=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID,\n\tDKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_LOW,SPF_HELO_PASS,SPF_PASS\n\tautolearn=disabled version=4.0.1 OzLabs 8", "X-Spam-Checker-Version": "SpamAssassin 4.0.1 (2024-03-25) on lists.ozlabs.org" }, "content": "With lazy PTE page table allocation, split_huge_pmd_if_needed() and\nthus vma_adjust_trans_huge() can now fail if order-0 allocation\nfor pagetable fails when trying to split. It is important to check\nif this failure occurred to prevent a huge PMD straddling at VMA\nboundary.\n\nThe vma_adjust_trans_huge() call is moved before vma_prepare() in all\nthree callers (__split_vma, vma_shrink, commit_merge). Previously it sat\nbetween vma_prepare() and vma_complete(), where there is no mechanism to\nabort - once vma_prepare() has been called, we must reach vma_complete().\nBy moving the call earlier, a split failure can return -ENOMEM cleanly\nwithout needing to undo VMA preparation.\n\nThis move is safe because vma_adjust_trans_huge() acquires its own\npmd_lock() internally and does not depend on any locks or state changes\nfrom vma_prepare(). The VMA boundaries are also unchanged at the new\ncall site, satisfying __split_huge_pmd_locked()'s requirement that the\nVMA covers the full PMD range.\n\nAll 3 callers (__split_vma, vma_shrink, commit_merge) already return\n-ENOMEM if there are allocation failures for other reasons (failure in\nvma_iter_prealloc for example), this follows the same pattern.\n\nSigned-off-by: Usama Arif <usama.arif@linux.dev>\n---\n include/linux/huge_mm.h | 13 ++++++-----\n mm/huge_memory.c | 21 +++++++++++++-----\n mm/vma.c | 37 +++++++++++++++++++++----------\n tools/testing/vma/include/stubs.h | 9 ++++----\n 4 files changed, 53 insertions(+), 27 deletions(-)", "diff": "diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h\nindex b081ce044c735..224965fce4e66 100644\n--- a/include/linux/huge_mm.h\n+++ b/include/linux/huge_mm.h\n@@ -483,8 +483,8 @@ int hugepage_madvise(struct vm_area_struct *vma, vm_flags_t *vm_flags,\n \t\t int advice);\n int madvise_collapse(struct vm_area_struct *vma, unsigned long start,\n \t\t unsigned long end, bool *lock_dropped);\n-void vma_adjust_trans_huge(struct vm_area_struct *vma, unsigned long start,\n-\t\t\t unsigned long end, struct vm_area_struct *next);\n+int vma_adjust_trans_huge(struct vm_area_struct *vma, unsigned long start,\n+\t\t\t unsigned long end, struct vm_area_struct *next);\n spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma);\n spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma);\n \n@@ -685,11 +685,12 @@ static inline int madvise_collapse(struct vm_area_struct *vma,\n \treturn -EINVAL;\n }\n \n-static inline void vma_adjust_trans_huge(struct vm_area_struct *vma,\n-\t\t\t\t\t unsigned long start,\n-\t\t\t\t\t unsigned long end,\n-\t\t\t\t\t struct vm_area_struct *next)\n+static inline int vma_adjust_trans_huge(struct vm_area_struct *vma,\n+\t\t\t\t\tunsigned long start,\n+\t\t\t\t\tunsigned long end,\n+\t\t\t\t\tstruct vm_area_struct *next)\n {\n+\treturn 0;\n }\n static inline spinlock_t *pmd_trans_huge_lock(pmd_t *pmd,\n \t\tstruct vm_area_struct *vma)\ndiff --git a/mm/huge_memory.c b/mm/huge_memory.c\nindex 976a1c74c0870..99f3b8b24c682 100644\n--- a/mm/huge_memory.c\n+++ b/mm/huge_memory.c\n@@ -3326,20 +3326,31 @@ static inline int split_huge_pmd_if_needed(struct vm_area_struct *vma, unsigned\n \treturn 0;\n }\n \n-void vma_adjust_trans_huge(struct vm_area_struct *vma,\n+int vma_adjust_trans_huge(struct vm_area_struct *vma,\n \t\t\t unsigned long start,\n \t\t\t unsigned long end,\n \t\t\t struct vm_area_struct *next)\n {\n+\tint err;\n+\n \t/* Check if we need to split start first. */\n-\tsplit_huge_pmd_if_needed(vma, start);\n+\terr = split_huge_pmd_if_needed(vma, start);\n+\tif (err)\n+\t\treturn err;\n \n \t/* Check if we need to split end next. */\n-\tsplit_huge_pmd_if_needed(vma, end);\n+\terr = split_huge_pmd_if_needed(vma, end);\n+\tif (err)\n+\t\treturn err;\n \n \t/* If we're incrementing next->vm_start, we might need to split it. */\n-\tif (next)\n-\t\tsplit_huge_pmd_if_needed(next, end);\n+\tif (next) {\n+\t\terr = split_huge_pmd_if_needed(next, end);\n+\t\tif (err)\n+\t\t\treturn err;\n+\t}\n+\n+\treturn 0;\n }\n \n static void unmap_folio(struct folio *folio)\ndiff --git a/mm/vma.c b/mm/vma.c\nindex a43f3c5d4b3dd..b4a3839a8036e 100644\n--- a/mm/vma.c\n+++ b/mm/vma.c\n@@ -513,6 +513,15 @@ __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,\n \t\t\treturn err;\n \t}\n \n+\t/*\n+\t * Split any THP straddling the split boundary before splitting\n+\t * the VMA itself. Do this before vma_prepare() so we can\n+\t * cleanly fail without undoing VMA preparation.\n+\t */\n+\terr = vma_adjust_trans_huge(vma, vma->vm_start, addr, NULL);\n+\tif (err)\n+\t\treturn err;\n+\n \tnew = vm_area_dup(vma);\n \tif (!new)\n \t\treturn -ENOMEM;\n@@ -550,11 +559,6 @@ __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,\n \tvp.insert = new;\n \tvma_prepare(&vp);\n \n-\t/*\n-\t * Get rid of huge pages and shared page tables straddling the split\n-\t * boundary.\n-\t */\n-\tvma_adjust_trans_huge(vma, vma->vm_start, addr, NULL);\n \tif (is_vm_hugetlb_page(vma))\n \t\thugetlb_split(vma, addr);\n \n@@ -732,6 +736,7 @@ static int commit_merge(struct vma_merge_struct *vmg)\n {\n \tstruct vm_area_struct *vma;\n \tstruct vma_prepare vp;\n+\tint err;\n \n \tif (vmg->__adjust_next_start) {\n \t\t/* We manipulate middle and adjust next, which is the target. */\n@@ -743,6 +748,16 @@ static int commit_merge(struct vma_merge_struct *vmg)\n \t\tvma_iter_config(vmg->vmi, vmg->start, vmg->end);\n \t}\n \n+\t/*\n+\t * THP pages may need to do additional splits if we increase\n+\t * middle->vm_start. Do this before vma_prepare() so we can\n+\t * cleanly fail without undoing VMA preparation.\n+\t */\n+\terr = vma_adjust_trans_huge(vma, vmg->start, vmg->end,\n+\t\t\t\t vmg->__adjust_middle_start ? vmg->middle : NULL);\n+\tif (err)\n+\t\treturn err;\n+\n \tinit_multi_vma_prep(&vp, vma, vmg);\n \n \t/*\n@@ -755,12 +770,6 @@ static int commit_merge(struct vma_merge_struct *vmg)\n \t\treturn -ENOMEM;\n \n \tvma_prepare(&vp);\n-\t/*\n-\t * THP pages may need to do additional splits if we increase\n-\t * middle->vm_start.\n-\t */\n-\tvma_adjust_trans_huge(vma, vmg->start, vmg->end,\n-\t\t\t vmg->__adjust_middle_start ? vmg->middle : NULL);\n \tvma_set_range(vma, vmg->start, vmg->end, vmg->pgoff);\n \tvmg_adjust_set_range(vmg);\n \tvma_iter_store_overwrite(vmg->vmi, vmg->target);\n@@ -1248,9 +1257,14 @@ int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma,\n \t unsigned long start, unsigned long end, pgoff_t pgoff)\n {\n \tstruct vma_prepare vp;\n+\tint err;\n \n \tWARN_ON((vma->vm_start != start) && (vma->vm_end != end));\n \n+\terr = vma_adjust_trans_huge(vma, start, end, NULL);\n+\tif (err)\n+\t\treturn err;\n+\n \tif (vma->vm_start < start)\n \t\tvma_iter_config(vmi, vma->vm_start, start);\n \telse\n@@ -1263,7 +1277,6 @@ int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma,\n \n \tinit_vma_prep(&vp, vma);\n \tvma_prepare(&vp);\n-\tvma_adjust_trans_huge(vma, start, end, NULL);\n \n \tvma_iter_clear(vmi);\n \tvma_set_range(vma, start, end, pgoff);\ndiff --git a/tools/testing/vma/include/stubs.h b/tools/testing/vma/include/stubs.h\nindex a30b8bc849557..952e3cc88ef10 100644\n--- a/tools/testing/vma/include/stubs.h\n+++ b/tools/testing/vma/include/stubs.h\n@@ -419,11 +419,12 @@ static inline int vma_dup_policy(struct vm_area_struct *src, struct vm_area_stru\n \treturn 0;\n }\n \n-static inline void vma_adjust_trans_huge(struct vm_area_struct *vma,\n-\t\t\t\t\t unsigned long start,\n-\t\t\t\t\t unsigned long end,\n-\t\t\t\t\t struct vm_area_struct *next)\n+static inline int vma_adjust_trans_huge(struct vm_area_struct *vma,\n+\t\t\t\t\tunsigned long start,\n+\t\t\t\t\tunsigned long end,\n+\t\t\t\t\tstruct vm_area_struct *next)\n {\n+\treturn 0;\n }\n \n static inline void hugetlb_split(struct vm_area_struct *, unsigned long) {}\n", "prefixes": [ "v3", "02/24" ] }