The patch titled
Subject: avr32/mm/fault.c: port OOM changes to do_page_fault
has been added to the -mm tree. Its filename is
avr32-mm-faultc-port-oom-changes-to-do_page_fault.patch
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From: Kautuk Consul <consul.kautuk@xxxxxxxxx>
Subject: avr32/mm/fault.c: port OOM changes to do_page_fault
Commits d065bd810b6de ("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.
Signed-off-by: Mohd. Faris <mohdfarisq2010@xxxxxxxxx>
Signed-off-by: Kautuk Consul <consul.kautuk@xxxxxxxxx>
Acked-by: Havard Skinnemoen <hskinnemoen@xxxxxxxxx>
Cc: Hans-Christian Egtvedt <egtvedt@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/avr32/mm/fault.c | 33 +++++++++++++++++++++++++--------
1 file changed, 25 insertions(+), 8 deletions(-)
diff -puN arch/avr32/mm/fault.c~avr32-mm-faultc-port-oom-changes-to-do_page_fault arch/avr32/mm/fault.c
--- a/arch/avr32/mm/fault.c~avr32-mm-faultc-port-oom-changes-to-do_page_fault
+++ a/arch/avr32/mm/fault.c
@@ -61,10 +61,10 @@ asmlinkage void do_page_fault(unsigned l
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 l
local_irq_enable();
+retry:
down_read(&mm->mmap_sem);
vma = find_vma(mm, address);
@@ -104,7 +105,6 @@ asmlinkage void do_page_fault(unsigned l
*/
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;
_
Subject: Subject: avr32/mm/fault.c: port OOM changes to do_page_fault
Patches currently in -mm which might be from consul.kautuk@xxxxxxxxx are
avr32-mm-faultc-port-oom-changes-to-do_page_fault.patch
avr32-mm-faultc-port-oom-changes-to-do_page_fault-fix.patch
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