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Commit f397c077 authored by Kautuk Consul's avatar Kautuk Consul Committed by Michal Simek
Browse files

microblaze: 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 microblaze.

Signed-off-by: default avatarKautuk Consul <consul.kautuk@gmail.com>
parent 59516b07

arch/microblaze/mm/fault.c

+28 −5
Original line number Diff line number Diff line
@@ -92,6 +92,8 @@ void do_page_fault(struct pt_regs *regs, unsigned long address, 
	int code = SEGV_MAPERR;

	int is_write = error_code & ESR_S;

	int fault;

	unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |

					 (is_write ? FAULT_FLAG_WRITE : 0);



	regs->ear = address;

	regs->esr = error_code;
@@ -138,6 +140,7 @@ void do_page_fault(struct pt_regs *regs, unsigned long address, 
		if (kernel_mode(regs) && !search_exception_tables(regs->pc))

			goto bad_area_nosemaphore;



retry:

		down_read(&mm->mmap_sem);

	}
@@ -210,7 +213,11 @@ void do_page_fault(struct pt_regs *regs, unsigned long address, 
	 * make sure we exit gracefully rather than endlessly redo

	 * the fault.

	 */

	fault = handle_mm_fault(mm, vma, address, is_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;
@@ -218,11 +225,27 @@ void do_page_fault(struct pt_regs *regs, unsigned long address, 
			goto do_sigbus;

		BUG();

	}



	if (flags & FAULT_FLAG_ALLOW_RETRY) {

		if (unlikely(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);



	/*

	 * keep track of tlb+htab misses that are good addrs but

	 * just need pte's created via handle_mm_fault()