mm/nds32: use general page fault accounting (daf7bf5d) · 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:

Greentime Hu <green.hu@gmail.com> Cc: Nick Hu <nickhu@andestech.com> Cc: Vincent Chen <deanbo422@gmail.com> Link: http://lkml.kernel.org/r/20200707225021.200906-13-peterx@redhat.com Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

arch/nds32/mm/fault.c

+3 −16

Original line number	Diff line number	Diff line
		@@ -121,6 +121,8 @@ void do_page_fault(unsigned long entry, unsigned long addr,
		if (unlikely(faulthandler_disabled() \|\| !mm))
		goto no_context;

		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);

		/*
		* As per x86, we may deadlock here. However, since the kernel only
		* validly references user space from well defined areas of the code,
		@@ -206,7 +208,7 @@ good_area:
		* the fault.
		*/

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

		/*
		* If we need to retry but a fatal signal is pending, handle the
		@@ -228,22 +230,7 @@ good_area:
		goto bad_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.
		*/
		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
		if (flags & FAULT_FLAG_ALLOW_RETRY) {
		if (fault & VM_FAULT_MAJOR) {
		tsk->maj_flt++;
		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ,
		1, regs, addr);
		} else {
		tsk->min_flt++;
		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN,
		1, regs, addr);
		}
		if (fault & VM_FAULT_RETRY) {
		flags \|= FAULT_FLAG_TRIED;

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