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Commit c29554f5 authored by Kautuk Consul's avatar Kautuk Consul Committed by David S. Miller
Browse files

sparc/mm/fault_32.c: Port OOM changes to do_sparc_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 32-bit sparc.

Signed-off-by: default avatarKautuk Consul <consul.kautuk@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7358e510

arch/sparc/mm/fault_32.c

+30 −7
Original line number Diff line number Diff line
@@ -225,6 +225,8 @@ asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write, 
	unsigned long g2;

	int from_user = !(regs->psr & PSR_PS);

	int fault, code;

	unsigned int flags = (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |

			      (write ? FAULT_FLAG_WRITE : 0));



	if(text_fault)

		address = regs->pc;
@@ -251,6 +253,7 @@ asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write, 


	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);



retry:

	down_read(&mm->mmap_sem);



	/*
@@ -289,7 +292,11 @@ asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write, 
	 * 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;
@@ -297,13 +304,29 @@ asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write, 
			goto do_sigbus;

		BUG();

	}



	if (flags & FAULT_FLAG_ALLOW_RETRY) {

		if (fault & VM_FAULT_MAJOR) {

			current->maj_flt++;

		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, address);

			perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ,

				      1, regs, address);

		} else {

			current->min_flt++;

		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, address);

			perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN,

				      1, regs, address);

		}

		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;