The patch titled
Subject: mm/mremap: avoid unneeded do_munmap call
has been added to the -mm tree. Its filename is
mm-mremap-avoid-unneeded-do_munmap-call.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-mremap-avoid-unneeded-do_munmap-call.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-mremap-avoid-unneeded-do_munmap-call.patch
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------------------------------------------------------
From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Subject: mm/mremap: avoid unneeded do_munmap call
When old_len == new_len, do_munmap will return -EINVAL due to len == 0.
This errno will be simply ignored because of old_len != new_len check. So
it is unnecessary to call do_munmap when old_len == new_len because
nothing is actually done.
Link: https://lkml.kernel.org/r/20220401081023.37080-1-linmiaohe@xxxxxxxxxx
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mremap.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/mm/mremap.c~mm-mremap-avoid-unneeded-do_munmap-call
+++ a/mm/mremap.c
@@ -820,9 +820,9 @@ static unsigned long mremap_to(unsigned
goto out;
}
- if (old_len >= new_len) {
+ if (old_len > new_len) {
ret = do_munmap(mm, addr+new_len, old_len - new_len, uf_unmap);
- if (ret && old_len != new_len)
+ if (ret)
goto out;
old_len = new_len;
}
_
Patches currently in -mm which might be from linmiaohe@xxxxxxxxxx are
mm-mempolicy-fix-mpol_new-leak-in-shared_policy_replace.patch
mm-shmem-make-shmem_init-return-void.patch
mm-memcg-remove-unneeded-nr_scanned.patch
mm-mmapc-use-helper-mlock_future_check.patch
mm-mremap-use-helper-mlock_future_check.patch
mm-mremap-avoid-unneeded-do_munmap-call.patch
mm-z3fold-declare-z3fold_mount-with-__init.patch
mm-z3fold-remove-obsolete-comment-in-z3fold_alloc.patch
mm-z3fold-minor-clean-up-for-z3fold_free.patch
mm-z3fold-remove-unneeded-page_mapcount_reset-and-clearpageprivate.patch
mm-z3fold-remove-confusing-local-variable-l-reassignment.patch
mm-z3fold-move-decrement-of-pool-pages_nr-into-__release_z3fold_page.patch
mm-z3fold-remove-redundant-list_del_init-of-zhdr-buddy-in-z3fold_free.patch
mm-z3fold-remove-unneeded-page_headless-check-in-free_handle.patch
mm-compaction-use-helper-isolation_suitable.patch
mm-migration-remove-unneeded-local-variable-mapping_locked.patch
mm-migration-remove-unneeded-out-label.patch
mm-migration-remove-unneeded-local-variable-page_lru.patch
mm-migration-fix-the-confusing-pagetranshuge-check.patch
mm-migration-use-helper-function-vma_lookup-in-add_page_for_migration.patch
mm-migration-use-helper-macro-min-in-do_pages_stat.patch
mm-migration-avoid-unneeded-nodemask_t-initialization.patch
mm-migration-remove-some-duplicated-codes-in-migrate_pages.patch
mm-migration-fix-potential-page-refcounts-leak-in-migrate_pages.patch
mm-migration-fix-potential-invalid-node-access-for-reclaim-based-migration.patch
mm-migration-fix-possible-do_pages_stat_array-racing-with-memory-offline.patch
