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authorMauro Carvalho Chehab <mchehab@redhat.com>2012-11-28 07:22:38 -0200
committerMauro Carvalho Chehab <mchehab@redhat.com>2012-11-28 07:22:38 -0200
commitd033a308d81ec83908760a15a841c2bd0d5e0ea3 (patch)
tree647abd67987fe4d7fee80105fc823edf3f53b4f6 /mm/rmap.c
parentc6c22955f80f2db9614b01fe5a3d1cfcd8b3d848 (diff)
parente23739b4ade80a3a7f87198f008f6c44a7cbc9fd (diff)
Merge remote-tracking branch 'linus/master' into staging/for_v3.8
* linus/master: (1428 commits) futex: avoid wake_futex() for a PI futex_q watchdog: using u64 in get_sample_period() writeback: put unused inodes to LRU after writeback completion mm: vmscan: check for fatal signals iff the process was throttled Revert "mm: remove __GFP_NO_KSWAPD" proc: check vma->vm_file before dereferencing UAPI: strip the _UAPI prefix from header guards during header installation include/linux/bug.h: fix sparse warning related to BUILD_BUG_ON_INVALID Linux 3.7-rc7 powerpc/eeh: Do not invalidate PE properly ALSA: hda - Fix build without CONFIG_PM of/address: sparc: Declare of_iomap as an extern function for sparc again PM / QoS: fix wrong error-checking condition bnx2x: remove redundant warning log vxlan: fix command usage in its doc 8139cp: revert "set ring address before enabling receiver" MPI: Fix compilation on MIPS with GCC 4.4 and newer MIPS: Fix crash that occurs when function tracing is enabled MIPS: Merge overlapping bootmem ranges jbd: Fix lock ordering bug in journal_unmap_buffer() ...
Diffstat (limited to 'mm/rmap.c')
-rw-r--r--mm/rmap.c20
1 files changed, 15 insertions, 5 deletions
diff --git a/mm/rmap.c b/mm/rmap.c
index 7df7984d476c..2ee1ef0f317b 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -56,6 +56,7 @@
#include <linux/mmu_notifier.h>
#include <linux/migrate.h>
#include <linux/hugetlb.h>
+#include <linux/backing-dev.h>
#include <asm/tlbflush.h>
@@ -926,11 +927,8 @@ int page_mkclean(struct page *page)
if (page_mapped(page)) {
struct address_space *mapping = page_mapping(page);
- if (mapping) {
+ if (mapping)
ret = page_mkclean_file(mapping, page);
- if (page_test_and_clear_dirty(page_to_pfn(page), 1))
- ret = 1;
- }
}
return ret;
@@ -1116,6 +1114,7 @@ void page_add_file_rmap(struct page *page)
*/
void page_remove_rmap(struct page *page)
{
+ struct address_space *mapping = page_mapping(page);
bool anon = PageAnon(page);
bool locked;
unsigned long flags;
@@ -1138,8 +1137,19 @@ void page_remove_rmap(struct page *page)
* this if the page is anon, so about to be freed; but perhaps
* not if it's in swapcache - there might be another pte slot
* containing the swap entry, but page not yet written to swap.
+ *
+ * And we can skip it on file pages, so long as the filesystem
+ * participates in dirty tracking; but need to catch shm and tmpfs
+ * and ramfs pages which have been modified since creation by read
+ * fault.
+ *
+ * Note that mapping must be decided above, before decrementing
+ * mapcount (which luckily provides a barrier): once page is unmapped,
+ * it could be truncated and page->mapping reset to NULL at any moment.
+ * Note also that we are relying on page_mapping(page) to set mapping
+ * to &swapper_space when PageSwapCache(page).
*/
- if ((!anon || PageSwapCache(page)) &&
+ if (mapping && !mapping_cap_account_dirty(mapping) &&
page_test_and_clear_dirty(page_to_pfn(page), 1))
set_page_dirty(page);
/*