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authorKautuk Consul <consul.kautuk@gmail.com>2012-07-30 14:39:21 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-07-30 17:25:11 -0700
commitf107701f011e681a21b95259f950bf9c836884e0 (patch)
tree9d84473e8d20396f1c08dd21fd168d9a4f9ccc09 /arch/xtensa
parent54b501992dd2a839e94e76aa392c392b55080ce8 (diff)
downloadlinux-linaro-stable-f107701f011e681a21b95259f950bf9c836884e0.tar.gz
xtensa/mm/fault.c: port OOM changes to do_page_fault
Commits d065bd810b6d ("mm: retry page fault when blocking on disk transfer") and 37b23e0525d3 ("x86,mm: make pagefault killable") introduced changes into the x86 pagefault handler for making the page fault handler retryable as well as killable. These changes reduce the mmap_sem hold time, which is crucial during OOM killer invocation. Port these changes to xtensa. Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com> Acked-by: Chris Zankel <chris@zankel.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/xtensa')
-rw-r--r--arch/xtensa/mm/fault.c29
1 files changed, 24 insertions, 5 deletions
diff --git a/arch/xtensa/mm/fault.c b/arch/xtensa/mm/fault.c
index b17885a0b508..5a74c53bc69c 100644
--- a/arch/xtensa/mm/fault.c
+++ b/arch/xtensa/mm/fault.c
@@ -44,6 +44,7 @@ void do_page_fault(struct pt_regs *regs)
int is_write, is_exec;
int fault;
+ unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
info.si_code = SEGV_MAPERR;
@@ -71,6 +72,7 @@ void do_page_fault(struct pt_regs *regs)
address, exccause, regs->pc, is_write? "w":"", is_exec? "x":"");
#endif
+retry:
down_read(&mm->mmap_sem);
vma = find_vma(mm, address);
@@ -93,6 +95,7 @@ good_area:
if (is_write) {
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
+ flags |= FAULT_FLAG_WRITE;
} else if (is_exec) {
if (!(vma->vm_flags & VM_EXEC))
goto bad_area;
@@ -104,7 +107,11 @@ good_area:
* make sure we exit gracefully rather than endlessly redo
* the fault.
*/
- fault = handle_mm_fault(mm, vma, address, is_write ? FAULT_FLAG_WRITE : 0);
+ fault = handle_mm_fault(mm, vma, address, flags);
+
+ if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
+ return;
+
if (unlikely(fault & VM_FAULT_ERROR)) {
if (fault & VM_FAULT_OOM)
goto out_of_memory;
@@ -112,10 +119,22 @@ good_area:
goto do_sigbus;
BUG();
}
- if (fault & VM_FAULT_MAJOR)
- current->maj_flt++;
- else
- current->min_flt++;
+ if (flags & FAULT_FLAG_ALLOW_RETRY) {
+ if (fault & VM_FAULT_MAJOR)
+ current->maj_flt++;
+ else
+ current->min_flt++;
+ if (fault & VM_FAULT_RETRY) {
+ flags &= ~FAULT_FLAG_ALLOW_RETRY;
+
+ /* No need to up_read(&mm->mmap_sem) as we would
+ * have already released it in __lock_page_or_retry
+ * in mm/filemap.c.
+ */
+
+ goto retry;
+ }
+ }
up_read(&mm->mmap_sem);
return;