The patch titled
Subject: mempolicy: mpol_shared_policy_init() without pseudo-vma
has been added to the -mm mm-unstable branch. Its filename is
mempolicy-mpol_shared_policy_init-without-pseudo-vma.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mempolicy-mpol_shared_policy_init-without-pseudo-vma.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Hugh Dickins <hughd@xxxxxxxxxx>
Subject: mempolicy: mpol_shared_policy_init() without pseudo-vma
Date: Tue, 3 Oct 2023 02:22:59 -0700 (PDT)
mpol_shared_policy_init() does not need to use a pseudo-vma: it can use
sp_alloc() and sp_insert() directly, since the object's shared policy tree
is empty and inaccessible (needing no lock) at get_inode() time.
Link: https://lkml.kernel.org/r/3bef62d8-ae78-4c2-533-56a44ae425c@xxxxxxxxxx
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Nhat Pham <nphamcs@xxxxxxxxx>
Cc: Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx>
Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Tejun heo <tj@xxxxxxxxxx>
Cc: Vishal Moola (Oracle) <vishal.moola@xxxxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Cc: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mempolicy.c | 28 ++++++++++++++--------------
1 file changed, 14 insertions(+), 14 deletions(-)
--- a/mm/mempolicy.c~mempolicy-mpol_shared_policy_init-without-pseudo-vma
+++ a/mm/mempolicy.c
@@ -2736,30 +2736,30 @@ void mpol_shared_policy_init(struct shar
rwlock_init(&sp->lock);
if (mpol) {
- struct vm_area_struct pvma;
- struct mempolicy *new;
+ struct sp_node *sn;
+ struct mempolicy *npol;
NODEMASK_SCRATCH(scratch);
if (!scratch)
goto put_mpol;
- /* contextualize the tmpfs mount point mempolicy */
- new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask);
- if (IS_ERR(new))
+
+ /* contextualize the tmpfs mount point mempolicy to this file */
+ npol = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask);
+ if (IS_ERR(npol))
goto free_scratch; /* no valid nodemask intersection */
task_lock(current);
- ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch);
+ ret = mpol_set_nodemask(npol, &mpol->w.user_nodemask, scratch);
task_unlock(current);
if (ret)
- goto put_new;
-
- /* Create pseudo-vma that contains just the policy */
- vma_init(&pvma, NULL);
- pvma.vm_end = TASK_SIZE; /* policy covers entire file */
- mpol_set_shared_policy(sp, &pvma, new); /* adds ref */
+ goto put_npol;
-put_new:
- mpol_put(new); /* drop initial ref */
+ /* alloc node covering entire file; adds ref to file's npol */
+ sn = sp_alloc(0, MAX_LFS_FILESIZE >> PAGE_SHIFT, npol);
+ if (sn)
+ sp_insert(sp, sn);
+put_npol:
+ mpol_put(npol); /* drop initial ref on file's npol */
free_scratch:
NODEMASK_SCRATCH_FREE(scratch);
put_mpol:
_
Patches currently in -mm which might be from hughd@xxxxxxxxxx are
hugetlbfs-drop-shared-numa-mempolicy-pretence.patch
kernfs-drop-shared-numa-mempolicy-hooks.patch
mempolicy-fix-migrate_pages2-syscall-return-nr_failed.patch
mempolicy-trivia-delete-those-ancient-pr_debugs.patch
mempolicy-trivia-slightly-more-consistent-naming.patch
mempolicy-trivia-use-pgoff_t-in-shared-mempolicy-tree.patch
mempolicy-mpol_shared_policy_init-without-pseudo-vma.patch
mempolicy-remove-confusing-mpol_mf_lazy-dead-code.patch
mm-add-page_rmappable_folio-wrapper.patch
mempolicy-alloc_pages_mpol-for-numa-policy-without-vma.patch
mempolicy-mmap_lock-is-not-needed-while-migrating-folios.patch
mempolicy-migration-attempt-to-match-interleave-nodes.patch
