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Commit 11fd9824 authored by Kautuk Consul's avatar Kautuk Consul Committed by Paul Mundt
Browse files

sh/mm/fault_32.c: Port OOM changes to 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 the 32-bit SH platform.

Signed-off-by: default avatarKautuk Consul <consul.kautuk@gmail.com>
Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent bbb4ce50

arch/sh/mm/fault_32.c

+29 −9
Original line number Diff line number Diff line
@@ -129,6 +129,8 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, 
	int si_code;

	int fault;

	siginfo_t info;

	unsigned int flags = (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |

			      (writeaccess ? FAULT_FLAG_WRITE : 0));



	tsk = current;

	mm = tsk->mm;
@@ -169,6 +171,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, 
	if (in_atomic() || !mm)

		goto no_context;



retry:

	down_read(&mm->mmap_sem);



	vma = find_vma(mm, address);
@@ -200,7 +203,11 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, 
	 * make 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;
@@ -208,6 +215,8 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, 
			goto do_sigbus;

		BUG();

	}



	if (flags & FAULT_FLAG_ALLOW_RETRY) {

		if (fault & VM_FAULT_MAJOR) {

			tsk->maj_flt++;

			perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
@@ -217,6 +226,17 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, 
			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;