The patch titled
Subject: mm/hugeltb: simplify the return code of __vma_reservation_common()
has been added to the -mm tree. Its filename is
mm-hugeltb-simplify-the-return-code-of-__vma_reservation_common.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-hugeltb-simplify-the-return-code-of-__vma_reservation_common.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-hugeltb-simplify-the-return-code-of-__vma_reservation_common.patch
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From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Subject: mm/hugeltb: simplify the return code of __vma_reservation_common()
It's guaranteed that the vma is associated with a resv_map, i.e. either
VM_MAYSHARE or HPAGE_RESV_OWNER, when the code reaches here or we would
have returned via !resv check above. So it's unneeded to check whether
HPAGE_RESV_OWNER is set here. Simplify the return code to make it more
clear.
Link: https://lkml.kernel.org/r/20210410072348.20437-3-linmiaohe@xxxxxxxxxx
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Feilong Lin <linfeilong@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb.c | 41 ++++++++++++++++++++---------------------
1 file changed, 20 insertions(+), 21 deletions(-)
--- a/mm/hugetlb.c~mm-hugeltb-simplify-the-return-code-of-__vma_reservation_common
+++ a/mm/hugetlb.c
@@ -2174,27 +2174,26 @@ static long __vma_reservation_common(str
if (vma->vm_flags & VM_MAYSHARE)
return ret;
- else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) && ret >= 0) {
- /*
- * In most cases, reserves always exist for private mappings.
- * However, a file associated with mapping could have been
- * hole punched or truncated after reserves were consumed.
- * As subsequent fault on such a range will not use reserves.
- * Subtle - The reserve map for private mappings has the
- * opposite meaning than that of shared mappings. If NO
- * entry is in the reserve map, it means a reservation exists.
- * If an entry exists in the reserve map, it means the
- * reservation has already been consumed. As a result, the
- * return value of this routine is the opposite of the
- * value returned from reserve map manipulation routines above.
- */
- if (ret)
- return 0;
- else
- return 1;
- }
- else
- return ret < 0 ? ret : 0;
+ /*
+ * We know private mapping must have HPAGE_RESV_OWNER set.
+ *
+ * In most cases, reserves always exist for private mappings.
+ * However, a file associated with mapping could have been
+ * hole punched or truncated after reserves were consumed.
+ * As subsequent fault on such a range will not use reserves.
+ * Subtle - The reserve map for private mappings has the
+ * opposite meaning than that of shared mappings. If NO
+ * entry is in the reserve map, it means a reservation exists.
+ * If an entry exists in the reserve map, it means the
+ * reservation has already been consumed. As a result, the
+ * return value of this routine is the opposite of the
+ * value returned from reserve map manipulation routines above.
+ */
+ if (ret > 0)
+ return 0;
+ if (ret == 0)
+ return 1;
+ return ret;
}
static long vma_needs_reservation(struct hstate *h,
_
Patches currently in -mm which might be from linmiaohe@xxxxxxxxxx are
mm-hugetlb-remove-redundant-reservation-check-condition-in-alloc_huge_page.patch
mm-hugetlb-use-some-helper-functions-to-cleanup-code.patch
mm-hugetlb-optimize-the-surplus-state-transfer-code-in-move_hugetlb_state.patch
hugetlb_cgroup-remove-unnecessary-vm_bug_on_page-in-hugetlb_cgroup_migrate.patch
mm-hugetlb-simplify-the-code-when-alloc_huge_page-failed-in-hugetlb_no_page.patch
mm-hugetlb-avoid-calculating-fault_mutex_hash-in-truncate_op-case.patch
khugepaged-remove-unneeded-return-value-of-khugepaged_collapse_pte_mapped_thps.patch
khugepaged-reuse-the-smp_wmb-inside-__setpageuptodate.patch
khugepaged-use-helper-khugepaged_test_exit-in-__khugepaged_enter.patch
khugepaged-fix-wrong-result-value-for-trace_mm_collapse_huge_page_isolate.patch
mm-huge_memoryc-remove-unnecessary-local-variable-ret2.patch
mm-huge_memoryc-rework-the-function-vma_adjust_trans_huge.patch
mm-huge_memoryc-make-get_huge_zero_page-return-bool.patch
mm-huge_memoryc-rework-the-function-do_huge_pmd_numa_page-slightly.patch
mm-huge_memoryc-remove-redundant-pagecompound-check.patch
mm-huge_memoryc-remove-unused-macro-transparent_hugepage_debug_cow_flag.patch
mm-huge_memoryc-use-helper-function-migration_entry_to_page.patch
khugepaged-use-helper-function-range_in_vma-in-collapse_pte_mapped_thp.patch
khugepaged-remove-unnecessary-out-label-in-collapse_huge_page.patch
khugepaged-remove-meaningless-pte_present-check-in-khugepaged_scan_pmd.patch
mm-hugeltb-remove-redundant-vm_bug_on-in-region_add.patch
mm-hugeltb-simplify-the-return-code-of-__vma_reservation_common.patch
mm-hugeltb-clarify-chg-freed-wont-go-negative-in-hugetlb_unreserve_pages.patch
mm-hugeltb-handle-the-error-case-in-hugetlb_fix_reserve_counts.patch
mm-hugetlb-remove-unused-variable-pseudo_vma-in-remove_inode_hugepages.patch
mm-migratec-make-putback_movable_page-static.patch
mm-migratec-remove-unnecessary-rc-=-migratepage_success-check-in-else-case.patch
mm-migratec-fix-potential-indeterminate-pte-entry-in-migrate_vma_insert_page.patch
mm-migratec-use-helper-migrate_vma_collect_skip-in-migrate_vma_collect_hole.patch
revert-mm-migrate-skip-shared-exec-thp-for-numa-balancing.patch
ksm-remove-redundant-vm_bug_on_page-on-stable_tree_search.patch
ksm-use-get_ksm_page_nolock-to-get-ksm-page-in-remove_rmap_item_from_tree.patch
ksm-remove-dedicated-macro-ksm_flag_mask.patch
ksm-fix-potential-missing-rmap_item-for-stable_node.patch
