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authorEric Dumazet <dada1@cosmosbay.com>2006-03-25 03:08:19 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-25 08:23:01 -0800
commitd74beb9f33a5f16d2965f11b275e401f225c949d (patch)
tree48f851753ebe9c9c8dd701dcdd0c5e1d7c629579 /kernel
parent34f361ade2fb4a869f6a7714d01c04ce4cfa75d9 (diff)
downloadlinux-sh-d74beb9f33a5f16d2965f11b275e401f225c949d.tar.gz
[PATCH] Use unsigned int types for a faster bsearch
This patch avoids arithmetic on 'signed' types that are slower than 'unsigned'. This saves space and cpu cycles. size of kernel/sys.o before the patch (gcc-3.4.5) text data bss dec hex filename 10924 252 4 11180 2bac kernel/sys.o size of kernel/sys.o after the patch text data bss dec hex filename 10903 252 4 11159 2b97 kernel/sys.o I noticed that gcc-4.1.0 (from Fedora Core 5) even uses idiv instruction for (a+b)/2 if a and b are signed. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sys.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/sys.c b/kernel/sys.c
index 119fb0d9e24e..38bc73ede2ba 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1363,7 +1363,7 @@ static void groups_sort(struct group_info *group_info)
/* a simple bsearch */
int groups_search(struct group_info *group_info, gid_t grp)
{
- int left, right;
+ unsigned int left, right;
if (!group_info)
return 0;
@@ -1371,7 +1371,7 @@ int groups_search(struct group_info *group_info, gid_t grp)
left = 0;
right = group_info->ngroups;
while (left < right) {
- int mid = (left+right)/2;
+ unsigned int mid = (left+right)/2;
int cmp = grp - GROUP_AT(group_info, mid);
if (cmp > 0)
left = mid + 1;