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authorAlexander Duyck <alexander.h.duyck@linux.intel.com>2019-02-15 14:44:12 -0800
committerDavid S. Miller <davem@davemloft.net>2019-02-17 15:48:43 -0800
commit8644772637deb121f7ac2df690cbf83fa63d3b70 (patch)
treeea32aa83dd30a3cb7491dc2d33c55971b00ce363
parente09c6a4ec1bb9ed73b4157b69c261e408d875b0f (diff)
mm: Use fixed constant in page_frag_alloc instead of size + 1
This patch replaces the size + 1 value introduced with the recent fix for 1 byte allocs with a constant value. The idea here is to reduce code overhead as the previous logic would have to read size into a register, then increment it, and write it back to whatever field was being used. By using a constant we can avoid those memory reads and arithmetic operations in favor of just encoding the maximum value into the operation itself. Fixes: 2c2ade81741c ("mm: page_alloc: fix ref bias in page_frag_alloc() for 1-byte allocs") Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--mm/page_alloc.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 46285d28e43b..7f79b78bc829 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4675,11 +4675,11 @@ refill:
/* Even if we own the page, we do not use atomic_set().
* This would break get_page_unless_zero() users.
*/
- page_ref_add(page, size);
+ page_ref_add(page, PAGE_FRAG_CACHE_MAX_SIZE);
/* reset page count bias and offset to start of new frag */
nc->pfmemalloc = page_is_pfmemalloc(page);
- nc->pagecnt_bias = size + 1;
+ nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1;
nc->offset = size;
}
@@ -4695,10 +4695,10 @@ refill:
size = nc->size;
#endif
/* OK, page count is 0, we can safely set it */
- set_page_count(page, size + 1);
+ set_page_count(page, PAGE_FRAG_CACHE_MAX_SIZE + 1);
/* reset page count bias and offset to start of new frag */
- nc->pagecnt_bias = size + 1;
+ nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1;
offset = size - fragsz;
}