diff options
| author | Peter Collingbourne <pcc@google.com> | 2023-02-16 11:59:24 -0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-03-28 16:20:09 -0700 |
| commit | 16d91faf09be148d9c1cf4999f4d15fb24a7cd72 (patch) | |
| tree | 6233936ca8de999f2b0eeb46d27b12f91cc3b687 /include/linux/highmem.h | |
| parent | af7df1c986adfe0684cb0b91114e0ac442b942e9 (diff) | |
| download | linux-16d91faf09be148d9c1cf4999f4d15fb24a7cd72.tar.gz | |
kasan: call clear_page with a match-all tag instead of changing page tag
Instead of changing the page's tag solely in order to obtain a pointer
with a match-all tag and then changing it back again, just convert the
pointer that we get from kmap_atomic() into one with a match-all tag
before passing it to clear_page().
On a certain microarchitecture, this has been observed to cause a
measurable improvement in microbenchmark performance, presumably as a
result of being able to avoid the atomic operations on the page tag.
Link: https://lkml.kernel.org/r/20230216195924.3287772-1-pcc@google.com
Signed-off-by: Peter Collingbourne <pcc@google.com>
Link: https://linux-review.googlesource.com/id/I0249822cc29097ca7a04ad48e8eb14871f80e711
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux/highmem.h')
| -rw-r--r-- | include/linux/highmem.h | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/include/linux/highmem.h b/include/linux/highmem.h index 8fc10089e19e8e..9c7cdaa3de8cdd 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -243,12 +243,10 @@ static inline void clear_highpage(struct page *page) static inline void clear_highpage_kasan_tagged(struct page *page) { - u8 tag; + void *kaddr = kmap_local_page(page); - tag = page_kasan_tag(page); - page_kasan_tag_reset(page); - clear_highpage(page); - page_kasan_tag_set(page, tag); + clear_page(kasan_reset_tag(kaddr)); + kunmap_local(kaddr); } #ifndef __HAVE_ARCH_TAG_CLEAR_HIGHPAGE |