mm/mips: use general page fault accounting (2558fd7f) · Commits · 戴 / test

Use the general page fault accounting by passing regs into handle_mm_fault(). It naturally solve the issue of multiple page fault accounting when page fault retry happened. Fix PERF_COUNT_SW_PAGE_FAULTS perf event manually for page fault retries, by moving it before taking mmap_sem. Signed-off-by:

Peter Xu <peterx@redhat.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Acked-by:

Thomas Bogendoerfer <tsbogend@alpha.franken.de> Link: http://lkml.kernel.org/r/20200707225021.200906-12-peterx@redhat.com Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

arch/mips/mm/fault.c

+3 −11

Original line number	Diff line number	Diff line
		@@ -96,6 +96,8 @@ static void __kprobes __do_page_fault(struct pt_regs *regs, unsigned long write,

		if (user_mode(regs))
		flags \|= FAULT_FLAG_USER;

		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
		retry:
		mmap_read_lock(mm);
		vma = find_vma(mm, address);
		@@ -152,12 +154,11 @@ good_area:
		* make sure we exit gracefully rather than endlessly redo
		* the fault.
		*/
		fault = handle_mm_fault(vma, address, flags, NULL);
		fault = handle_mm_fault(vma, address, flags, regs);

		if (fault_signal_pending(fault, regs))
		return;

		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
		if (unlikely(fault & VM_FAULT_ERROR)) {
		if (fault & VM_FAULT_OOM)
		goto out_of_memory;
		@@ -168,15 +169,6 @@ good_area:
		BUG();
		}
		if (flags & FAULT_FLAG_ALLOW_RETRY) {
		if (fault & VM_FAULT_MAJOR) {
		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
		regs, address);
		tsk->maj_flt++;
		} else {
		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1,
		regs, address);
		tsk->min_flt++;
		}
		if (fault & VM_FAULT_RETRY) {
		flags \|= FAULT_FLAG_TRIED;

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