The patch titled
Subject: hugetlb_cgroup: fix imbalanced css_get and css_put pair for shared mappings
has been added to the -mm tree. Its filename is
hugetlb_cgroup-fix-imbalanced-css_get-and-css_put-pair-for-shared-mappings-v3.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/hugetlb_cgroup-fix-imbalanced-css_get-and-css_put-pair-for-shared-mappings-v3.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/hugetlb_cgroup-fix-imbalanced-css_get-and-css_put-pair-for-shared-mappings-v3.patch
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------------------------------------------------------
From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Subject: hugetlb_cgroup: fix imbalanced css_get and css_put pair for shared mappings
reshape some comments, per Mike
Link: https://lkml.kernel.org/r/20210316023002.53921-1-linmiaohe@xxxxxxxxxx
Fixes: 075a61d07a8e ("hugetlb_cgroup: add accounting for shared mappings")
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Reported-by: kernel test robot <lkp@xxxxxxxxx> (auto build test ERROR)
Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: Wanpeng Li <liwp.linux@xxxxxxxxx>
Cc: Mina Almasry <almasrymina@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb.c | 13 ++++++-------
mm/hugetlb_cgroup.c | 3 +--
2 files changed, 7 insertions(+), 9 deletions(-)
--- a/mm/hugetlb.c~hugetlb_cgroup-fix-imbalanced-css_get-and-css_put-pair-for-shared-mappings-v3
+++ a/mm/hugetlb.c
@@ -281,13 +281,12 @@ static void record_hugetlb_cgroup_unchar
&h_cg->rsvd_hugepage[hstate_index(h)];
nrg->css = &h_cg->css;
/*
- * The caller (hugetlb_reserve_pages now) will only hold one
- * h_cg->css reference for the whole contiguous reservation
- * region. But this area might be scattered when there are
- * already some file_regions reside in it. As a result, many
- * file_regions may share only one h_cg->css reference. In
- * order to ensure that one file_region must hold and only
- * hold one h_cg->css reference, we should do css_get for
+ * The caller will hold exactly one h_cg->css reference for the
+ * whole contiguous reservation region. But this area might be
+ * scattered when there are already some file_regions reside in
+ * it. As a result, many file_regions may share only one css
+ * reference. In order to ensure that one file_region must hold
+ * exactly one h_cg->css reference, we should do css_get for
* each file_region and leave the reference held by caller
* untouched.
*/
--- a/mm/hugetlb_cgroup.c~hugetlb_cgroup-fix-imbalanced-css_get-and-css_put-pair-for-shared-mappings-v3
+++ a/mm/hugetlb_cgroup.c
@@ -403,8 +403,7 @@ void hugetlb_cgroup_uncharge_file_region
nr_pages * resv->pages_per_hpage);
/*
* Only do css_put(rg->css) when we delete the entire region
- * because one file_region must hold and only hold one rg->css
- * reference.
+ * because one file_region must hold exactly one css reference.
*/
if (region_del)
css_put(rg->css);
_
Patches currently in -mm which might be from linmiaohe@xxxxxxxxxx are
hugetlb_cgroup-fix-imbalanced-css_get-and-css_put-pair-for-shared-mappings.patch
hugetlb_cgroup-fix-imbalanced-css_get-and-css_put-pair-for-shared-mappings-v3.patch
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
