Commit f3f09d5a authored by Kautuk Consul's avatar Kautuk Consul Committed by Guan Xuetao
Browse files

unicore32/mm/fault.c: Port OOM changes to do_pf 



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 unicore32.

Signed-off-by: default avatarKautuk Consul <consul.kautuk@gmail.com>
Acked-by: default avatarGuan Xuetao <gxt@mprc.pku.edu.cn>
parent 0e4a43ed

arch/unicore32/mm/fault.c

+27 −10
Original line number Diff line number Diff line
@@ -168,7 +168,7 @@ static inline bool access_error(unsigned int fsr, struct vm_area_struct *vma) 
}



static int __do_pf(struct mm_struct *mm, unsigned long addr, unsigned int fsr,

		struct task_struct *tsk)

		unsigned int flags, struct task_struct *tsk)

{

	struct vm_area_struct *vma;

	int fault;
@@ -194,14 +194,7 @@ good_area: 
	 * If for any reason at all we couldn't handle the fault, make

	 * sure we exit gracefully rather than endlessly redo the fault.

	 */

	fault = handle_mm_fault(mm, vma, addr & PAGE_MASK,

			    (!(fsr ^ 0x12)) ? FAULT_FLAG_WRITE : 0);

	if (unlikely(fault & VM_FAULT_ERROR))

		return fault;

	if (fault & VM_FAULT_MAJOR)

		tsk->maj_flt++;

	else

		tsk->min_flt++;

	fault = handle_mm_fault(mm, vma, addr & PAGE_MASK, flags);

	return fault;



check_stack:
@@ -216,6 +209,8 @@ static int do_pf(unsigned long addr, unsigned int fsr, struct pt_regs *regs) 
	struct task_struct *tsk;

	struct mm_struct *mm;

	int fault, sig, code;

	unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |

				 ((!(fsr ^ 0x12)) ? FAULT_FLAG_WRITE : 0);



	tsk = current;

	mm = tsk->mm;
@@ -236,6 +231,7 @@ static int do_pf(unsigned long addr, unsigned int fsr, struct pt_regs *regs) 
		if (!user_mode(regs)

		    && !search_exception_tables(regs->UCreg_pc))

			goto no_context;

retry:

		down_read(&mm->mmap_sem);

	} else {

		/*
@@ -251,7 +247,28 @@ static int do_pf(unsigned long addr, unsigned int fsr, struct pt_regs *regs) 
#endif

	}



	fault = __do_pf(mm, addr, fsr, tsk);

	fault = __do_pf(mm, addr, fsr, flags, tsk);



	/* If we need to retry but a fatal signal is pending, handle the

	 * signal first. We do not need to release the mmap_sem because

	 * it would already be released in __lock_page_or_retry in

	 * mm/filemap.c. */

	if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))

		return 0;



	if (!(fault & VM_FAULT_ERROR) && (flags & FAULT_FLAG_ALLOW_RETRY)) {

		if (fault & VM_FAULT_MAJOR)

			tsk->maj_flt++;

		else

			tsk->min_flt++;

		if (fault & VM_FAULT_RETRY) {

			/* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk

			* of starvation. */

			flags &= ~FAULT_FLAG_ALLOW_RETRY;

			goto retry;

		}

	}



	up_read(&mm->mmap_sem);



	/*

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