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authorSergey Senozhatsky <sergey.senozhatsky@gmail.com>2015-04-15 16:16:15 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-04-15 16:35:22 -0700
commit495819ead5ad02174208994ca610852a7791a2f2 (patch)
tree3e1c75d7ceefac98519dfae8c181e9b1712bc0f6 /mm
parent1ec7cfb13acb8047ae5baafb43d2cd6b64ac85b9 (diff)
zsmalloc: micro-optimize zs_object_copy()
A micro-optimization. Avoid additional branching and reduce (a bit) registry pressure (f.e. s_off += size; d_off += size; may be calculated twise: first for >= PAGE_SIZE check and later for offset update in "else" clause). scripts/bloat-o-meter shows some improvement add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-10 (-10) function old new delta zs_object_copy 550 540 -10 Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/zsmalloc.c15
1 files changed, 7 insertions, 8 deletions
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 8705a010e2d3..a9a9ff233a13 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -1537,7 +1537,12 @@ static void zs_object_copy(unsigned long src, unsigned long dst,
if (written == class->size)
break;
- if (s_off + size >= PAGE_SIZE) {
+ s_off += size;
+ s_size -= size;
+ d_off += size;
+ d_size -= size;
+
+ if (s_off >= PAGE_SIZE) {
kunmap_atomic(d_addr);
kunmap_atomic(s_addr);
s_page = get_next_page(s_page);
@@ -1546,21 +1551,15 @@ static void zs_object_copy(unsigned long src, unsigned long dst,
d_addr = kmap_atomic(d_page);
s_size = class->size - written;
s_off = 0;
- } else {
- s_off += size;
- s_size -= size;
}
- if (d_off + size >= PAGE_SIZE) {
+ if (d_off >= PAGE_SIZE) {
kunmap_atomic(d_addr);
d_page = get_next_page(d_page);
BUG_ON(!d_page);
d_addr = kmap_atomic(d_page);
d_size = class->size - written;
d_off = 0;
- } else {
- d_off += size;
- d_size -= size;
}
}

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