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authorKautuk Consul <consul.kautuk@gmail.com>2012-07-30 14:39:25 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-07-30 17:25:11 -0700
commitbf7c27e9887af48952743753916f9cfbe900d0e9 (patch)
tree500736901ab3cc72e7f90332602d1419897ae1f9 /arch/avr32/mm
parent7eafef6d1d712aa9973c3cbd0013a5b66d5a6604 (diff)
downloadlinux-bf7c27e9887af48952743753916f9cfbe900d0e9.tar.gz
avr32/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 AVR32. [akpm@linux-foundation.org: fix comment layout] Signed-off-by: Mohd. Faris <mohdfarisq2010@gmail.com> Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com> Acked-by: Havard Skinnemoen <hskinnemoen@gmail.com> Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/avr32/mm')
-rw-r--r--arch/avr32/mm/fault.c33
1 files changed, 25 insertions, 8 deletions
diff --git a/arch/avr32/mm/fault.c b/arch/avr32/mm/fault.c
index f7040a1..b92e609 100644
--- a/arch/avr32/mm/fault.c
+++ b/arch/avr32/mm/fault.c
@@ -61,10 +61,10 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs)
const struct exception_table_entry *fixup;
unsigned long address;
unsigned long page;
- int writeaccess;
long signr;
int code;
int fault;
+ unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
if (notify_page_fault(regs, ecr))
return;
@@ -86,6 +86,7 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs)
local_irq_enable();
+retry:
down_read(&mm->mmap_sem);
vma = find_vma(mm, address);
@@ -104,7 +105,6 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs)
*/
good_area:
code = SEGV_ACCERR;
- writeaccess = 0;
switch (ecr) {
case ECR_PROTECTION_X:
@@ -121,7 +121,7 @@ good_area:
case ECR_TLB_MISS_W:
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
- writeaccess = 1;
+ flags |= FAULT_FLAG_WRITE;
break;
default:
panic("Unhandled case %lu in do_page_fault!", ecr);
@@ -132,7 +132,11 @@ good_area:
* sure we exit gracefully rather than endlessly redo the
* fault.
*/
- fault = handle_mm_fault(mm, vma, address, writeaccess ? 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;
@@ -140,10 +144,23 @@ good_area:
goto do_sigbus;
BUG();
}
- if (fault & VM_FAULT_MAJOR)
- tsk->maj_flt++;
- else
- tsk->min_flt++;
+
+ if (flags & FAULT_FLAG_ALLOW_RETRY) {
+ if (fault & VM_FAULT_MAJOR)
+ tsk->maj_flt++;
+ else
+ tsk->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;