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[89.27.86.246]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-5b8d46e0966sm191742e87.55.2026.09.21.22.35.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Sep 2026 22:35:01 -0700 (PDT) From: mpenttil@redhat.com To: linux-mm@kvack.org Cc: dri-devel@lists.freedesktop.org, intel-xe@lists.freedesktop.org, linux-kernel@vger.kernel.org, =?UTF-8?q?Mika=20Penttil=C3=A4?= , David Hildenbrand , Jason Gunthorpe , Leon Romanovsky , Alistair Popple , Balbir Singh , Zi Yan , Matthew Brost , Andrew Morton , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko Subject: [PATCH v14 08/12] mm/hmm: add lazy MMU mode support for migration in HMM pagewalk Date: Tue, 22 Sep 2026 08:34:17 +0300 Message-ID: <20260922053421.4092027-9-mpenttil@redhat.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260922053421.4092027-1-mpenttil@redhat.com> References: <20260922053421.4092027-1-mpenttil@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Mika Penttilä Add calls to lazy_mmu_mode_enable() and lazy_mmu_mode_disable() while doing migration. Cc: David Hildenbrand Cc: Jason Gunthorpe Cc: Leon Romanovsky Cc: Alistair Popple Cc: Balbir Singh Cc: Zi Yan Cc: Matthew Brost Suggested-by: Alistair Popple Signed-off-by: Mika Penttilä --- mm/hmm.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/mm/hmm.c b/mm/hmm.c index a1459bd34c04..a67a23e54551 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -371,6 +371,7 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr, /* Report error for everything else */ if (hmm_vma_walk->ptelocked) { + lazy_mmu_mode_disable(); pte_unmap_unlock(ptep, hmm_vma_walk->ptl); hmm_vma_walk->ptelocked = false; } else { @@ -394,6 +395,7 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr, !is_zero_pfn(pte_pfn(pte))) { if (hmm_pte_need_fault(hmm_vma_walk, pfn_req_flags, 0)) { if (hmm_vma_walk->ptelocked) { + lazy_mmu_mode_disable(); pte_unmap_unlock(ptep, hmm_vma_walk->ptl); hmm_vma_walk->ptelocked = false; } else { @@ -413,6 +415,7 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr, fault: if (hmm_vma_walk->ptelocked) { + lazy_mmu_mode_disable(); pte_unmap_unlock(ptep, hmm_vma_walk->ptl); hmm_vma_walk->ptelocked = false; } else { @@ -510,6 +513,7 @@ static int migrate_vma_split_folio(struct folio *folio, if (folio != fault_folio) folio_get(folio); + lazy_mmu_mode_disable(); pte_unmap_unlock(ptep, hmm_vma_walk->ptl); hmm_vma_walk->ptelocked = false; @@ -1135,8 +1139,10 @@ static int hmm_vma_walk_pmd(pmd_t *pmdp, if (minfo) { ptep = pte_offset_map_lock(mm, pmdp, addr, &hmm_vma_walk->ptl); - if (ptep) + if (ptep) { + lazy_mmu_mode_enable(); hmm_vma_walk->ptelocked = true; + } } else { ptep = pte_offset_map(pmdp, addr); } @@ -1178,6 +1184,7 @@ static int hmm_vma_walk_pmd(pmd_t *pmdp, flush_tlb_range(walk->vma, start, addr); if (hmm_vma_walk->ptelocked) { + lazy_mmu_mode_disable(); pte_unmap_unlock(ptep - 1, hmm_vma_walk->ptl); hmm_vma_walk->ptelocked = false; } else { -- 2.55.0