mm/arc: use general page fault accounting (52e3f8d0) · 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> Cc: Vineet Gupta <vgupta@synopsys.com> Link: http://lkml.kernel.org/r/20200707225021.200906-4-peterx@redhat.com Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

arch/arc/mm/fault.c

+3 −15

Original line number	Diff line number	Diff line
		@@ -105,6 +105,7 @@ void do_page_fault(unsigned long address, struct pt_regs *regs)
		if (write)
		flags \|= FAULT_FLAG_WRITE;

		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
		retry:
		mmap_read_lock(mm);

		@@ -130,7 +131,7 @@ retry:
		goto bad_area;
		}

		fault = handle_mm_fault(vma, address, flags, NULL);
		fault = handle_mm_fault(vma, address, flags, regs);

		/* Quick path to respond to signals */
		if (fault_signal_pending(fault, regs)) {
		@@ -155,22 +156,9 @@ bad_area:
		* Major/minor page fault accounting
		* (in case of retry we only land here once)
		*/
		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);

		if (likely(!(fault & VM_FAULT_ERROR))) {
		if (fault & VM_FAULT_MAJOR) {
		tsk->maj_flt++;
		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
		regs, address);
		} else {
		tsk->min_flt++;
		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1,
		regs, address);
		}

		if (likely(!(fault & VM_FAULT_ERROR)))
		/* Normal return path: fault Handled Gracefully */
		return;
		}

		if (!user_mode(regs))
		goto no_context;

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