diff options
| author |   Song Liu <songliubraving@fb.com> | 2019-09-23 15:38:03 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2019-09-24 15:54:11 -0700 |
| commit | 09d91cda0e8207c1f14ee0d572f61a53dbcdaf85 (patch) | |
| tree | 31686dc913d6904f0de79cecf644aa44e0cb49fc /mm | |
| parent | mm,thp: add read-only THP support for (non-shmem) FS (diff) | |
| download | linux-dev-09d91cda0e8207c1f14ee0d572f61a53dbcdaf85.tar.xz linux-dev-09d91cda0e8207c1f14ee0d572f61a53dbcdaf85.zip | |
mm,thp: avoid writes to file with THP in pagecache
In previous patch, an application could put part of its text section in
THP via madvise(). These THPs will be protected from writes when the
application is still running (TXTBSY). However, after the application
exits, the file is available for writes.
This patch avoids writes to file THP by dropping page cache for the file
when the file is open for write. A new counter nr_thps is added to struct
address_space. In do_dentry_open(), if the file is open for write and
nr_thps is non-zero, we drop page cache for the whole file.
Link: http://lkml.kernel.org/r/20190801184244.3169074-8-songliubraving@fb.com
Signed-off-by: Song Liu <songliubraving@fb.com>
Reported-by: kbuild test robot <lkp@intel.com>
Acked-by: Rik van Riel <riel@surriel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/filemap.c | 1 | ||||
| -rw-r--r-- | mm/khugepaged.c | 4 |
2 files changed, 4 insertions, 1 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index 91fe3a08ca4a..1146fcfa3215 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -205,6 +205,7 @@ static void unaccount_page_cache_page(struct address_space *mapping, __dec_node_page_state(page, NR_SHMEM_THPS); } else if (PageTransHuge(page)) { __dec_node_page_state(page, NR_FILE_THPS); + filemap_nr_thps_dec(mapping); } /* diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 8607c77431b3..e89430ec5267 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1514,8 +1514,10 @@ out_unlock: if (is_shmem) __inc_node_page_state(new_page, NR_SHMEM_THPS); - else + else { __inc_node_page_state(new_page, NR_FILE_THPS); + filemap_nr_thps_inc(mapping); + } if (nr_none) { struct zone *zone = page_zone(new_page); |