powerpc/mm: Handle VM_FAULT_RETRY earlier (14c02e41) · Commits · 戴 / test

arch/powerpc/mm/fault.c

+38 −29

Original line number	Diff line number	Diff line
		@@ -458,6 +458,26 @@ good_area:
		* the fault.
		*/
		fault = handle_mm_fault(vma, address, flags);

		/*
		* Handle the retry right now, the mmap_sem has been released in that
		* case.
		*/
		if (unlikely(fault & VM_FAULT_RETRY)) {
		/* We retry only once */
		if (flags & FAULT_FLAG_ALLOW_RETRY) {
		/*
		* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk
		* of starvation.
		*/
		flags &= ~FAULT_FLAG_ALLOW_RETRY;
		flags \|= FAULT_FLAG_TRIED;
		if (!fatal_signal_pending(current))
		goto retry;
		}
		/* We will enter mm_fault_error() below */
		}

		if (unlikely(fault & (VM_FAULT_RETRY\|VM_FAULT_ERROR))) {
		if (fault & VM_FAULT_SIGSEGV)
		goto bad_area;
		@@ -469,11 +489,8 @@ good_area:
		}

		/*
		* Major/minor page fault accounting is only done on the
		* initial attempt. If we go through a retry, it is extremely
		* likely that the page will be found in page cache at that point.
		* Major/minor page fault accounting.
		*/
		if (flags & FAULT_FLAG_ALLOW_RETRY) {
		if (fault & VM_FAULT_MAJOR) {
		current->maj_flt++;
		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
		@@ -494,14 +511,6 @@ good_area:
		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1,
		regs, address);
		}
		if (fault & VM_FAULT_RETRY) {
		/* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk
		* of starvation. */
		flags &= ~FAULT_FLAG_ALLOW_RETRY;
		flags \|= FAULT_FLAG_TRIED;
		goto retry;
		}
		}

		up_read(&mm->mmap_sem);
		goto bail;