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Commit f28fa729 authored by Kautuk Consul's avatar Kautuk Consul Committed by Tony Luck
Browse files

[IA64] Port OOM changes to ia64_do_page_fault 



Commit d065bd81
(mm: retry page fault when blocking on disk transfer) and
commit 37b23e05
(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 ia64.

Signed-off-by: default avatarKautuk Consul <consul.kautuk@gmail.com>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
parent cfaf0251

arch/ia64/mm/fault.c

+34 −12
Original line number Diff line number Diff line
@@ -72,6 +72,10 @@ mapped_kernel_page_is_present (unsigned long address) 
	return pte_present(pte);

}



#	define VM_READ_BIT	0

#	define VM_WRITE_BIT	1

#	define VM_EXEC_BIT	2



void __kprobes

ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *regs)

{
@@ -81,6 +85,12 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re 
	struct siginfo si;

	unsigned long mask;

	int fault;

	unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;



	mask = ((((isr >> IA64_ISR_X_BIT) & 1UL) << VM_EXEC_BIT)

		| (((isr >> IA64_ISR_W_BIT) & 1UL) << VM_WRITE_BIT));



	flags |= ((mask & VM_WRITE) ? FAULT_FLAG_WRITE : 0);



	/* mmap_sem is performance critical.... */

	prefetchw(&mm->mmap_sem);
@@ -109,6 +119,7 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re 
	if (notify_page_fault(regs, TRAP_BRKPT))

		return;



retry:

	down_read(&mm->mmap_sem);



	vma = find_vma_prev(mm, address, &prev_vma);
@@ -130,10 +141,6 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re 


	/* OK, we've got a good vm_area for this memory area.  Check the access permissions: */



#	define VM_READ_BIT	0

#	define VM_WRITE_BIT	1

#	define VM_EXEC_BIT	2



#	if (((1 << VM_READ_BIT) != VM_READ || (1 << VM_WRITE_BIT) != VM_WRITE) \

	    || (1 << VM_EXEC_BIT) != VM_EXEC)

#		error File is out of sync with <linux/mm.h>.  Please update.
@@ -142,9 +149,6 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re 
	if (((isr >> IA64_ISR_R_BIT) & 1UL) && (!(vma->vm_flags & (VM_READ | VM_WRITE))))

		goto bad_area;



	mask = (  (((isr >> IA64_ISR_X_BIT) & 1UL) << VM_EXEC_BIT)

		| (((isr >> IA64_ISR_W_BIT) & 1UL) << VM_WRITE_BIT));



	if ((vma->vm_flags & mask) != mask)

		goto bad_area;
@@ -153,7 +157,11 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re 
	 * sure we exit gracefully rather than endlessly redo the

	 * fault.

	 */

	fault = handle_mm_fault(mm, vma, address, (mask & VM_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)) {

		/*

		 * We ran out of memory, or some other thing happened
@@ -168,10 +176,24 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re 
		}

		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;