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Commit 3d7b6a67 authored by Kautuk Consul's avatar Kautuk Consul Committed by David Howells
Browse files

mn10300/mm/fault.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 mn10300.

Signed-off-by: default avatarKautuk Consul <consul.kautuk@gmail.com>
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
parent 83c2dc15

arch/mn10300/mm/fault.c

+25 −8
Original line number Diff line number Diff line
@@ -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;