From: Yang Shi <yang.shi@linux.alibaba.com>
To: mhocko@kernel.org, willy@infradead.org,
ldufour@linux.vnet.ibm.com, vbabka@suse.cz, kirill@shutemov.name,
akpm@linux-foundation.org
Cc: dave.hansen@intel.com, oleg@redhat.com,
srikar@linux.vnet.ibm.com, yang.shi@linux.alibaba.com,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [v11 PATCH 3/3] mm: unmap VM_PFNMAP mappings with optimized path
Date: Thu, 20 Sep 2018 01:03:41 +0800 [thread overview]
Message-ID: <1537376621-51150-4-git-send-email-yang.shi@linux.alibaba.com> (raw)
In-Reply-To: <1537376621-51150-1-git-send-email-yang.shi@linux.alibaba.com>
When unmapping VM_PFNMAP mappings, vm flags need to be updated. Since
the vmas have been detached, so it sounds safe to update vm flags with
read mmap_sem.
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
---
mm/mmap.c | 9 ---------
1 file changed, 9 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index 490340e..847a17d 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2771,15 +2771,6 @@ static int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
munlock_vma_pages_all(tmp);
}
- /*
- * Unmapping vmas, which have VM_HUGETLB or VM_PFNMAP,
- * need get done with write mmap_sem held since they may
- * update vm_flags.
- */
- if (downgrade &&
- (tmp->vm_flags & VM_PFNMAP))
- downgrade = false;
-
tmp = tmp->vm_next;
}
}
--
1.8.3.1
next prev parent reply other threads:[~2018-09-19 17:05 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-19 17:03 [v11 PATCH 0/3] mm: zap pages with read mmap_sem in munmap for large mapping Yang Shi
2018-09-19 17:03 ` [v11 PATCH 1/3] mm: mmap: zap pages with read mmap_sem in munmap Yang Shi
2018-09-26 11:09 ` Vlastimil Babka
2018-09-19 17:03 ` [v11 PATCH 2/3] mm: unmap VM_HUGETLB mappings with optimized path Yang Shi
2018-09-26 11:10 ` Vlastimil Babka
2018-09-19 17:03 ` Yang Shi [this message]
2018-09-26 11:11 ` [v11 PATCH 3/3] mm: unmap VM_PFNMAP " Vlastimil Babka
2018-09-26 12:35 ` [v11 PATCH 0/3] mm: zap pages with read mmap_sem in munmap for large mapping Kirill A. Shutemov
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