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Sat, 27 Jun 2026 04:41:47 -0700 (PDT) Date: Sat, 27 Jun 2026 11:41:47 +0000 From: Wei Yang To: Lance Yang Cc: Wei Yang , akpm@linux-foundation.org, ljs@kernel.org, riel@surriel.com, liam@infradead.org, vbabka@kernel.org, harry@kernel.org, jannh@google.com, ziy@nvidia.com, sj@kernel.org, balbirs@nvidia.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, "David Hildenbrand (Arm)" Subject: Re: [Patch mm-hotfixes v4] mm/page_vma_mapped: fix device-private PMD handling Message-ID: <20260627114147.d6csxmiha6whfyb2@master> Reply-To: Wei Yang References: <20260624065353.1622-1-richard.weiyang@gmail.com> <20260627020719.ipzfrlhfbvr6ac35@master> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) On Sat, Jun 27, 2026 at 10:59:16AM +0800, Lance Yang wrote: > > >On 2026/6/27 10:07, Wei Yang wrote: >[...] >> >> Hi David >> >> I did a little adjustment like below. Want to check with you at first. >> >> > >> > >From 048ecd33673ec649e168fbbb97749a7c0e344fcd Mon Sep 17 00:00:00 2001 >> > From: "David Hildenbrand (Arm)" >> > Date: Fri, 26 Jun 2026 12:03:40 +0200 >> > Subject: [PATCH] tmp >> > >> > Signed-off-by: David Hildenbrand (Arm) >> > --- >> > mm/page_vma_mapped.c | 29 +++++++++++++++++------------ >> > 1 file changed, 17 insertions(+), 12 deletions(-) >> > >> > diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c >> > index 2ccbabfb2cc17..ed2a23a90e8dd 100644 >> > --- a/mm/page_vma_mapped.c >> > +++ b/mm/page_vma_mapped.c >> > @@ -243,21 +243,31 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) >> > */ >> > pmde = pmdp_get_lockless(pvmw->pmd); >> > >> > - if (pmd_trans_huge(pmde) || pmd_is_migration_entry(pmde)) { >> > + if (pmd_trans_huge(pmde) || pmd_is_migration_entry(pmde) || >> > + pmd_is_device_private_entry(pmde)) { >> > pvmw->ptl = pmd_lock(mm, pvmw->pmd); >> > pmde = *pvmw->pmd; >> > - if (!pmd_present(pmde)) { >> > + if (pmd_is_migration_entry(pmde)) { >> > softleaf_t entry; >> > >> >> How about: >> const softleaf_t entry = softleaf_from_pmd(pmde); >> >> > - if (!thp_migration_supported() || >> > - !(pvmw->flags & PVMW_MIGRATION)) >> > + if (!(pvmw->flags & PVMW_MIGRATION)) >> > return not_found(pvmw); >> > entry = softleaf_from_pmd(pmde); >> >> could be removed. >> >> > + if (!check_pmd(softleaf_to_pfn(entry), pvmw)) >> > + return not_found(pvmw); >> > + return true; >> > + } else if (pmd_is_device_private_entry(pmde)) { >> > + softleaf_t entry; >> >> The same. >> >> > >> > - if (!softleaf_is_migration(entry) || >> > - !check_pmd(softleaf_to_pfn(entry), pvmw)) >> > + if (pvmw->flags & PVMW_MIGRATION) >> > + return not_found(pvmw); >> > + entry = softleaf_from_pmd(pmde); >> > + if (!check_pmd(softleaf_to_pfn(entry), pvmw)) >> > return not_found(pvmw); >> > return true; >> > + } else if (!pmd_present(pmde) ){ >> > + return not_found(pvmw); >> > } >> > if (likely(pmd_trans_huge(pmde))) { >> > if (pvmw->flags & PVMW_MIGRATION) >> >> How about merge this with above? And put at the first case? >> >> Below is what it looks like: > >Why add more churn to a fix with a stable tag? Cleanup can come later no? > OK, will leave it for future cleanup. -- Wei Yang Help you, Help me