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| author | Sergey Senozhatsky <sergey.senozhatsky@gmail.com> | 2015-04-15 16:16:15 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-04-15 16:35:22 -0700 |
| commit | 495819ead5ad02174208994ca610852a7791a2f2 (patch) | |
| tree | 3e1c75d7ceefac98519dfae8c181e9b1712bc0f6 | |
| parent | 1ec7cfb13acb8047ae5baafb43d2cd6b64ac85b9 (diff) | |
| download | linux-495819ead5ad02174208994ca610852a7791a2f2.tar.bz2 | |
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>
| -rw-r--r-- | mm/zsmalloc.c | 15 |
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; } } |