From: Yu Zhao <yuzhao@google.com>
To: Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@suse.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: "Peter Zijlstra" <peterz@infradead.org>,
"Ingo Molnar" <mingo@redhat.com>,
"Arnaldo Carvalho de Melo" <acme@kernel.org>,
"Alexander Shishkin" <alexander.shishkin@linux.intel.com>,
"Jiri Olsa" <jolsa@redhat.com>,
"Namhyung Kim" <namhyung@kernel.org>,
"Vlastimil Babka" <vbabka@suse.cz>,
"Hugh Dickins" <hughd@google.com>,
"Jérôme Glisse" <jglisse@redhat.com>,
"Andrea Arcangeli" <aarcange@redhat.com>,
"Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
"David Rientjes" <rientjes@google.com>,
"Matthew Wilcox" <willy@infradead.org>,
"Lance Roy" <ldr709@gmail.com>,
"Ralph Campbell" <rcampbell@nvidia.com>,
"Jason Gunthorpe" <jgg@ziepe.ca>,
"Dave Airlie" <airlied@redhat.com>,
"Thomas Hellstrom" <thellstrom@vmware.com>,
"Souptick Joarder" <jrdr.linux@gmail.com>,
"Mel Gorman" <mgorman@suse.de>, "Jan Kara" <jack@suse.cz>,
"Mike Kravetz" <mike.kravetz@oracle.com>,
"Huang Ying" <ying.huang@intel.com>,
"Aaron Lu" <ziqian.lzq@antfin.com>,
"Omar Sandoval" <osandov@fb.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Vineeth Remanan Pillai" <vpillai@digitalocean.com>,
"Daniel Jordan" <daniel.m.jordan@oracle.com>,
"Mike Rapoport" <rppt@linux.ibm.com>,
"Joel Fernandes" <joel@joelfernandes.org>,
"Mark Rutland" <mark.rutland@arm.com>,
"Alexander Duyck" <alexander.h.duyck@linux.intel.com>,
"Pavel Tatashin" <pavel.tatashin@microsoft.com>,
"David Hildenbrand" <david@redhat.com>,
"Juergen Gross" <jgross@suse.com>,
"Anthony Yznaga" <anthony.yznaga@oracle.com>,
"Johannes Weiner" <hannes@cmpxchg.org>,
"Darrick J . Wong" <darrick.wong@oracle.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
"Yu Zhao" <yuzhao@google.com>
Subject: [PATCH v3 1/4] mm: remove unnecessary smp_wmb() in collapse_huge_page()
Date: Tue, 24 Sep 2019 17:24:56 -0600 [thread overview]
Message-ID: <20190924232459.214097-1-yuzhao@google.com> (raw)
In-Reply-To: <20190914070518.112954-1-yuzhao@google.com>
__SetPageUptodate() always has a built-in smp_wmb() to make sure
user data copied to a new page appears before set_pmd_at().
Signed-off-by: Yu Zhao <yuzhao@google.com>
---
mm/khugepaged.c | 7 -------
1 file changed, 7 deletions(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index ccede2425c3f..70ff98e1414d 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1067,13 +1067,6 @@ static void collapse_huge_page(struct mm_struct *mm,
_pmd = mk_huge_pmd(new_page, vma->vm_page_prot);
_pmd = maybe_pmd_mkwrite(pmd_mkdirty(_pmd), vma);
- /*
- * spin_lock() below is not the equivalent of smp_wmb(), so
- * this is needed to avoid the copy_huge_page writes to become
- * visible after the set_pmd_at() write.
- */
- smp_wmb();
-
spin_lock(pmd_ptl);
BUG_ON(!pmd_none(*pmd));
page_add_new_anon_rmap(new_page, vma, address, true);
--
2.23.0.351.gc4317032e6-goog
next prev parent reply other threads:[~2019-09-24 23:25 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-08 22:56 [PATCH] mm: don't expose page to fast gup before it's ready Yu Zhao
2018-01-09 8:46 ` Michal Hocko
2018-01-09 10:10 ` Yu Zhao
2018-01-31 23:07 ` Andrew Morton
2019-05-14 21:25 ` Andrew Morton
2019-05-14 23:07 ` Yu Zhao
2019-09-14 7:05 ` [PATCH v2] mm: don't expose page to fast gup prematurely Yu Zhao
2019-09-24 11:23 ` Kirill A. Shutemov
2019-09-24 22:05 ` Yu Zhao
2019-09-25 12:17 ` Kirill A. Shutemov
2019-09-26 3:58 ` Yu Zhao
2019-09-24 23:24 ` Yu Zhao [this message]
2019-09-24 23:24 ` [PATCH v3 2/4] mm: don't expose hugetlb " Yu Zhao
2019-09-24 23:24 ` [PATCH v3 3/4] mm: don't expose non-hugetlb " Yu Zhao
2019-09-25 8:25 ` Peter Zijlstra
2019-09-25 22:26 ` Yu Zhao
2019-09-26 10:20 ` Kirill A. Shutemov
2019-09-27 3:26 ` John Hubbard
2019-09-27 12:33 ` Michal Hocko
[not found] ` <20190927050648.GA92494@google.com>
[not found] ` <712513fe-f064-c965-d165-80d43cfc606f@nvidia.com>
2019-10-02 0:00 ` Yu Zhao
2019-09-24 23:24 ` [PATCH v3 4/4] mm: remove unnecessary smp_wmb() in __SetPageUptodate() Yu Zhao
2019-09-24 23:50 ` Matthew Wilcox
2019-09-25 22:03 ` Yu Zhao
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