diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2013-05-02 17:56:31 -0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-05-02 17:56:31 -0400 |
commit | 0279b3c0ada1d78882f24acf94ac4595bd657a89 (patch) | |
tree | ba31505ea6581b840604493d0233857bb7ce58d1 /lib | |
parent | 797994f81a8b2bdca2eecffa415c1e7a89a4f961 (diff) | |
parent | f3002134158092178be81339ec5a22ff80e6c308 (diff) |
Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
"This fixes the cputime scaling overflow problems for good without
having bad 32-bit overhead, and gets rid of the div64_u64_rem() helper
as well."
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
Revert "math64: New div64_u64_rem helper"
sched: Avoid prev->stime underflow
sched: Do not account bogus utime
sched: Avoid cputime scaling overflow
Diffstat (limited to 'lib')
-rw-r--r-- | lib/div64.c | 19 |
1 files changed, 6 insertions, 13 deletions
diff --git a/lib/div64.c b/lib/div64.c index 3af5728d95fd..a163b6caef73 100644 --- a/lib/div64.c +++ b/lib/div64.c | |||
@@ -79,10 +79,9 @@ EXPORT_SYMBOL(div_s64_rem); | |||
79 | #endif | 79 | #endif |
80 | 80 | ||
81 | /** | 81 | /** |
82 | * div64_u64_rem - unsigned 64bit divide with 64bit divisor and 64bit remainder | 82 | * div64_u64 - unsigned 64bit divide with 64bit divisor |
83 | * @dividend: 64bit dividend | 83 | * @dividend: 64bit dividend |
84 | * @divisor: 64bit divisor | 84 | * @divisor: 64bit divisor |
85 | * @remainder: 64bit remainder | ||
86 | * | 85 | * |
87 | * This implementation is a modified version of the algorithm proposed | 86 | * This implementation is a modified version of the algorithm proposed |
88 | * by the book 'Hacker's Delight'. The original source and full proof | 87 | * by the book 'Hacker's Delight'. The original source and full proof |
@@ -90,33 +89,27 @@ EXPORT_SYMBOL(div_s64_rem); | |||
90 | * | 89 | * |
91 | * 'http://www.hackersdelight.org/HDcode/newCode/divDouble.c.txt' | 90 | * 'http://www.hackersdelight.org/HDcode/newCode/divDouble.c.txt' |
92 | */ | 91 | */ |
93 | #ifndef div64_u64_rem | 92 | #ifndef div64_u64 |
94 | u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder) | 93 | u64 div64_u64(u64 dividend, u64 divisor) |
95 | { | 94 | { |
96 | u32 high = divisor >> 32; | 95 | u32 high = divisor >> 32; |
97 | u64 quot; | 96 | u64 quot; |
98 | 97 | ||
99 | if (high == 0) { | 98 | if (high == 0) { |
100 | u32 rem32; | 99 | quot = div_u64(dividend, divisor); |
101 | quot = div_u64_rem(dividend, divisor, &rem32); | ||
102 | *remainder = rem32; | ||
103 | } else { | 100 | } else { |
104 | int n = 1 + fls(high); | 101 | int n = 1 + fls(high); |
105 | quot = div_u64(dividend >> n, divisor >> n); | 102 | quot = div_u64(dividend >> n, divisor >> n); |
106 | 103 | ||
107 | if (quot != 0) | 104 | if (quot != 0) |
108 | quot--; | 105 | quot--; |
109 | 106 | if ((dividend - quot * divisor) >= divisor) | |
110 | *remainder = dividend - quot * divisor; | ||
111 | if (*remainder >= divisor) { | ||
112 | quot++; | 107 | quot++; |
113 | *remainder -= divisor; | ||
114 | } | ||
115 | } | 108 | } |
116 | 109 | ||
117 | return quot; | 110 | return quot; |
118 | } | 111 | } |
119 | EXPORT_SYMBOL(div64_u64_rem); | 112 | EXPORT_SYMBOL(div64_u64); |
120 | #endif | 113 | #endif |
121 | 114 | ||
122 | /** | 115 | /** |