Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit bf7c27e9 authored by Kautuk Consul's avatar Kautuk Consul Committed by Linus Torvalds
Browse files

avr32/mm/fault.c: port OOM changes to do_page_fault 



Commits d065bd81 ("mm: retry page fault when blocking on disk
transfer") and 37b23e05 ("x86,mm: make pagefault killable")
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 AVR32.

[akpm@linux-foundation.org: fix comment layout]
Signed-off-by: default avatarMohd. Faris <mohdfarisq2010@gmail.com>
Signed-off-by: default avatarKautuk Consul <consul.kautuk@gmail.com>
Acked-by: default avatarHavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7eafef6d

arch/avr32/mm/fault.c

+25 −8
Original line number Diff line number Diff line
@@ -61,10 +61,10 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs) 
	const struct exception_table_entry *fixup;

	unsigned long address;

	unsigned long page;

	int writeaccess;

	long signr;

	int code;

	int fault;

	unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;



	if (notify_page_fault(regs, ecr))

		return;
@@ -86,6 +86,7 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs) 


	local_irq_enable();



retry:

	down_read(&mm->mmap_sem);



	vma = find_vma(mm, address);
@@ -104,7 +105,6 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs) 
	 */

good_area:

	code = SEGV_ACCERR;

	writeaccess = 0;



	switch (ecr) {

	case ECR_PROTECTION_X:
@@ -121,7 +121,7 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs) 
	case ECR_TLB_MISS_W:

		if (!(vma->vm_flags & VM_WRITE))

			goto bad_area;

		writeaccess = 1;

		flags |= FAULT_FLAG_WRITE;

		break;

	default:

		panic("Unhandled case %lu in do_page_fault!", ecr);
@@ -132,7 +132,11 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs) 
	 * 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;
@@ -140,10 +144,23 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs) 
			goto do_sigbus;

		BUG();

	}



	if (flags & FAULT_FLAG_ALLOW_RETRY) {

		if (fault & VM_FAULT_MAJOR)

			tsk->maj_flt++;

		else

			tsk->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;