From: Miaohe Lin <linmiaohe@huawei.com>
To: <akpm@linux-foundation.org>
Cc: <riel@redhat.com>, <kirill.shutemov@linux.intel.com>,
<ebru.akagunduz@gmail.com>, <dan.carpenter@oracle.com>,
<linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>,
<linmiaohe@huawei.com>
Subject: [PATCH 4/5] khugepaged: remove unnecessary mem_cgroup_uncharge() in collapse_[file|huge_page]
Date: Thu, 4 Mar 2021 07:30:12 -0500 [thread overview]
Message-ID: <20210304123013.23560-5-linmiaohe@huawei.com> (raw)
In-Reply-To: <20210304123013.23560-1-linmiaohe@huawei.com>
Since commit 7ae88534cdd9 ("mm: move mem_cgroup_uncharge out of
__page_cache_release()"), the mem_cgroup will be uncharged when hpage is
freed. Uncharge mem_cgroup here is harmless but it looks confusing and
buggy: if mem_cgroup charge failed, we will call mem_cgroup_uncharge()
uncorrectly in error path because hpage is not IS_ERR_OR_NULL().
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
---
mm/khugepaged.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index e886a8618c33..68579cdbdc9b 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1211,8 +1211,6 @@ static void collapse_huge_page(struct mm_struct *mm,
out_up_write:
mmap_write_unlock(mm);
out_nolock:
- if (!IS_ERR_OR_NULL(*hpage))
- mem_cgroup_uncharge(*hpage);
trace_mm_collapse_huge_page(mm, isolated, result);
return;
out:
@@ -1968,8 +1966,6 @@ static void collapse_file(struct mm_struct *mm,
unlock_page(new_page);
out:
VM_BUG_ON(!list_empty(&pagelist));
- if (!IS_ERR_OR_NULL(*hpage))
- mem_cgroup_uncharge(*hpage);
/* TODO: tracepoints */
}
--
2.19.1
next prev parent reply other threads:[~2021-03-04 12:32 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-04 12:30 [PATCH 0/5] Cleanup and fixup for khugepaged Miaohe Lin
2021-03-04 12:30 ` [PATCH 1/5] khugepaged: remove unneeded return value of khugepaged_collapse_pte_mapped_thps() Miaohe Lin
2021-03-04 12:30 ` [PATCH 2/5] khugepaged: reuse the smp_wmb() inside __SetPageUptodate() Miaohe Lin
2021-03-04 12:30 ` [PATCH 3/5] khugepaged: use helper khugepaged_test_exit() in __khugepaged_enter() Miaohe Lin
2021-03-04 12:30 ` Miaohe Lin [this message]
2021-03-05 17:38 ` [PATCH 4/5] khugepaged: remove unnecessary mem_cgroup_uncharge() in collapse_[file|huge_page] Kirill A. Shutemov
2021-03-06 3:18 ` Miaohe Lin
2021-03-04 12:30 ` [PATCH 5/5] khugepaged: fix wrong result value for trace_mm_collapse_huge_page_isolate() Miaohe Lin
2021-03-05 17:40 ` [PATCH 0/5] Cleanup and fixup for khugepaged Kirill A. Shutemov
2021-03-06 2:44 ` Miaohe Lin
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