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,
"Mika Penttilä" <mpenttil@redhat.com>,
"David Hildenbrand" <david@kernel.org>,
"Jason Gunthorpe" <jgg@nvidia.com>,
"Leon Romanovsky" <leonro@nvidia.com>,
"Alistair Popple" <apopple@nvidia.com>,
"Balbir Singh" <balbirs@nvidia.com>, "Zi Yan" <ziy@nvidia.com>,
"Matthew Brost" <matthew.brost@intel.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Lorenzo Stoakes" <ljs@kernel.org>,
"Liam R. Howlett" <Liam.Howlett@oracle.com>,
"Vlastimil Babka" <vbabka@suse.cz>,
"Mike Rapoport" <rppt@kernel.org>,
"Suren Baghdasaryan" <surenb@google.com>,
"Michal Hocko" <mhocko@suse.com>
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 [thread overview]
Message-ID: <20260922053421.4092027-9-mpenttil@redhat.com> (raw)
In-Reply-To: <20260922053421.4092027-1-mpenttil@redhat.com>
From: Mika Penttilä <mpenttil@redhat.com>
Add calls to lazy_mmu_mode_enable() and lazy_mmu_mode_disable()
while doing migration.
Cc: David Hildenbrand <david@kernel.org>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Leon Romanovsky <leonro@nvidia.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Suggested-by: Alistair Popple <apopple@nvidia.com>
Signed-off-by: Mika Penttilä <mpenttil@redhat.com>
---
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
next prev parent reply other threads:[~2026-09-22 5:35 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-22 5:34 [PATCH 00/12] [PATCH v14 00/12] migrate on fault for device pages mpenttil
2026-09-22 5:34 ` [PATCH v14 01/12] mm/Kconfig: changes for " mpenttil
2026-09-22 5:34 ` [PATCH v14 02/12] mm: add helper to convert HMM pfn to migrate pfn mpenttil
2026-09-22 5:34 ` [PATCH v14 03/12] mm/hmm: preparations for HMM to participate in migration mpenttil
2026-09-22 5:34 ` [PATCH v14 04/12] mm/hmm: do the plumbing " mpenttil
2026-09-22 5:34 ` [PATCH v14 05/12] mm/hmm: implement folio split for migrate needs in HMM pagewalk mpenttil
2026-09-22 5:34 ` [PATCH v14 06/12] mm/hmm: migrate collection in HMM pagewalk - pte level mpenttil
2026-09-22 5:34 ` [PATCH v14 07/12] mm/hmm: migrate collection in HMM pagewalk - pmd level mpenttil
2026-09-22 5:34 ` mpenttil [this message]
2026-09-22 5:34 ` [PATCH v14 09/12] mm/hmm: implement rollback for device page migration in HMM pagewalk mpenttil
2026-09-22 5:34 ` [PATCH v14 10/12] mm: enable device page migration from " mpenttil
2026-09-22 5:34 ` [PATCH v14 11/12] lib/test_hmm: add a new testcase for the migrate on fault mpenttil
2026-09-22 5:34 ` [PATCH v14 12/12] Documentation/mm/hmm: document migration through hmm_range_fault() mpenttil
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