diff options
| author | Eric Dumazet <dada1@cosmosbay.com> | 2007-12-24 20:57:56 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2008-01-28 15:00:05 -0800 |
| commit | 21371f768bf7127ee45bfaadd17899df6a439e8f (patch) | |
| tree | 91b5debf1d861a40c942a33f1286b70031a94305 | |
| parent | b15c4bcd15741b31019379298edfca28dc78029d (diff) | |
[SOCK] Avoid divides in sk_stream_pages() and __sk_stream_mem_reclaim()
sk_forward_alloc being signed, we should take care of divides by
SK_STREAM_MEM_QUANTUM we do in sk_stream_pages() and
__sk_stream_mem_reclaim()
This patchs introduces SK_STREAM_MEM_QUANTUM_SHIFT, defined
as ilog2(SK_STREAM_MEM_QUANTUM), to be able to use right
shifts instead of plain divides.
This should help compiler to choose right shifts instead of
expensive divides (as seen with CONFIG_CC_OPTIMIZE_FOR_SIZE=y on x86)
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/net/sock.h | 3 | ||||
| -rw-r--r-- | net/core/stream.c | 2 |
2 files changed, 3 insertions, 2 deletions
diff --git a/include/net/sock.h b/include/net/sock.h index e178b49eefb..d27ba6fdd03 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -716,10 +716,11 @@ extern void __sk_stream_mem_reclaim(struct sock *sk); extern int sk_stream_mem_schedule(struct sock *sk, int size, int kind); #define SK_STREAM_MEM_QUANTUM ((int)PAGE_SIZE) +#define SK_STREAM_MEM_QUANTUM_SHIFT ilog2(SK_STREAM_MEM_QUANTUM) static inline int sk_stream_pages(int amt) { - return DIV_ROUND_UP(amt, SK_STREAM_MEM_QUANTUM); + return (amt + SK_STREAM_MEM_QUANTUM - 1) >> SK_STREAM_MEM_QUANTUM_SHIFT; } static inline void sk_stream_mem_reclaim(struct sock *sk) diff --git a/net/core/stream.c b/net/core/stream.c index 5586879bb9b..bf188ffdbdb 100644 --- a/net/core/stream.c +++ b/net/core/stream.c @@ -196,7 +196,7 @@ EXPORT_SYMBOL(sk_stream_error); void __sk_stream_mem_reclaim(struct sock *sk) { - atomic_sub(sk->sk_forward_alloc / SK_STREAM_MEM_QUANTUM, + atomic_sub(sk->sk_forward_alloc >> SK_STREAM_MEM_QUANTUM_SHIFT, sk->sk_prot->memory_allocated); sk->sk_forward_alloc &= SK_STREAM_MEM_QUANTUM - 1; if (*sk->sk_prot->memory_pressure && |