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authorNick Piggin <npiggin@suse.de>2007-10-16 04:24:56 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-16 12:42:54 -0400
commit5fe172370687e03cc6ba8dca990b75db18ff9bb3 (patch)
tree8ce000fee15fa9ccd4313018f7f9ab1ffbc8cdaa /mm/filemap.c
parentae37461c70bc8c8416cad1bab13a9898ed030aa1 (diff)
mm: debug write deadlocks
Allow CONFIG_DEBUG_VM to switch off the prefaulting logic, to simulate the Makes the race much easier to hit. This is useful for demonstration and testing purposes, but is removed in a subsequent patch. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/filemap.c')
-rw-r--r--mm/filemap.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index f74d05201862..0c54fc9b8e3d 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1878,6 +1878,7 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov,
1878 if (maxlen > bytes) 1878 if (maxlen > bytes)
1879 maxlen = bytes; 1879 maxlen = bytes;
1880 1880
1881#ifndef CONFIG_DEBUG_VM
1881 /* 1882 /*
1882 * Bring in the user page that we will copy from _first_. 1883 * Bring in the user page that we will copy from _first_.
1883 * Otherwise there's a nasty deadlock on copying from the 1884 * Otherwise there's a nasty deadlock on copying from the
@@ -1885,6 +1886,7 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov,
1885 * up-to-date. 1886 * up-to-date.
1886 */ 1887 */
1887 fault_in_pages_readable(buf, maxlen); 1888 fault_in_pages_readable(buf, maxlen);
1889#endif
1888 1890
1889 page = __grab_cache_page(mapping,index,&cached_page,&lru_pvec); 1891 page = __grab_cache_page(mapping,index,&cached_page,&lru_pvec);
1890 if (!page) { 1892 if (!page) {