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mn10300/mm/fault.c: Port OOM changes to do_page_fault 

Commit d065bd810b
(mm: retry page fault when blocking on disk transfer) and
commit 37b23e0525
(x86,mm: make pagefault killable)

The above commits 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 mn10300.

Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
This commit is contained in:
Kautuk Consul 2012-12-12 15:36:39 +00:00 committed by David Howells
parent 83c2dc15ce
commit 3d7b6a674e
1 changed files with 25 additions and 8 deletions
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25
arch/mn10300/mm/fault.c
View File

@ -123,7 +123,8 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long fault_code,
struct mm_struct *mm;
unsigned long page;
siginfo_t info;
int write, fault;
int fault;
unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
#ifdef CONFIG_GDBSTUB
/* handle GDB stub causing a fault */
@ -170,6 +171,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long fault_code,
if (in_atomic() || !mm)
goto no_context;
retry:
down_read(&mm->mmap_sem);
vma = find_vma(mm, address);
@ -220,7 +222,6 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long fault_code,
*/
good_area:
info.si_code = SEGV_ACCERR;
write = 0;
switch (fault_code & (MMUFCR_xFC_PGINVAL|MMUFCR_xFC_TYPE)) {
default: /* 3: write, present */
case MMUFCR_xFC_TYPE_WRITE:
@ -232,7 +233,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long fault_code,
case MMUFCR_xFC_PGINVAL | MMUFCR_xFC_TYPE_WRITE:
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
write++;
flags |= FAULT_FLAG_WRITE;
break;
/* read from protected page */
@ -251,7 +252,11 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long fault_code,
* make sure we exit gracefully rather than endlessly redo
* the fault.
*/
fault = handle_mm_fault(mm, vma, address, 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;
@ -259,10 +264,22 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long fault_code,
goto do_sigbus;
BUG();
}
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;