Messages in this thread Patch in this message | | | From | jglisse@redhat ... | Subject | [RFC PATCH 1/4] uprobes: use set_pte_at() not set_pte_at_notify() | Date | Thu, 31 Jan 2019 13:37:03 -0500 |
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From: Jérôme Glisse <jglisse@redhat.com>
Using set_pte_at_notify() trigger useless calls to change_pte() so just use set_pte_at() instead. The reason is that set_pte_at_notify() should only be use when going from either a read and write pte to read only pte with same pfn, or from read only to read and write with a different pfn.
The set_pte_at_notify() was use because __replace_page() code came from the mm/ksm.c code in which the above rules are valid.
Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: kvm@vger.kernel.org --- kernel/events/uprobes.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 87e76a1dc758..a4807b1edd7f 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -207,8 +207,7 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr, flush_cache_page(vma, addr, pte_pfn(*pvmw.pte)); ptep_clear_flush_notify(vma, addr, pvmw.pte); - set_pte_at_notify(mm, addr, pvmw.pte, - mk_pte(new_page, vma->vm_page_prot)); + set_pte_at(mm, addr, pvmw.pte, mk_pte(new_page, vma->vm_page_prot)); page_remove_rmap(old_page, false); if (!page_mapped(old_page)) -- 2.17.1
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