From: Chen Gang <cheng...@emindsoft.com.cn>
In api itself, kernel does not use it -- it is divided into ac_etime_hi
and ac_etime_lo. So kernel side only need generate the correct
ac_etime_hi and ac_etime_lo, but need not know about comp2_t.
At present, kernel use normal u64 type for it, when kernel provdes it to
outside, kernel can translate it into ac_etime_hi and ac_etime_lo,
directly, but need not notice about comp2_t, in fact.
The patch notices about coding styles:
- Use 1 instead of 1ul, since type int is enough.
- Use white space between operator and constant or macro.
- Initialize variables directly, when declare it, since they need be
initialized and can be initialized by constant (include constant
macros).
- Remove redundant empty line.
Signed-off-by: Chen Gang <gang.chen.5...@gmail.com>
---
include/uapi/linux/acct.h | 6 ++++--
kernel/acct.c | 31 ++++++++++++++-----------------
2 files changed, 18 insertions(+), 19 deletions(-)
diff --git a/include/uapi/linux/acct.h b/include/uapi/linux/acct.h
index df2f9a0..97acdd4 100644
--- a/include/uapi/linux/acct.h
+++ b/include/uapi/linux/acct.h
@@ -24,12 +24,15 @@
* comp_t is a 16-bit "floating" point number with a 3-bit base 8
* exponent and a 13-bit fraction.
* comp2_t is 24-bit with 5-bit base 2 exponent and 20 bit fraction
- * (leading 1 not stored).
+ * (leading 1 not stored). And it is described as ac_etime_hi and
+ * ac_etime_lo in kernel.
* See linux/kernel/acct.c for the specific encoding systems used.
*/
typedef __u16 comp_t;
+#ifndef __KERNEL__
typedef __u32 comp2_t;
+#endif /* __KERNEL */
/*
* accounting file record
@@ -120,5 +123,4 @@ struct acct_v3
#define AHZ (HZ)
#endif /* __KERNEL */
-
#endif /* _UAPI_LINUX_ACCT_H */
diff --git a/kernel/acct.c b/kernel/acct.c
index 74963d1..f707a10 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -338,7 +338,7 @@ static comp_t encode_comp_t(unsigned long value)
#if ACCT_VERSION == 1 || ACCT_VERSION == 2
/*
- * encode an u64 into a comp2_t (24 bits)
+ * encode an u64 into ac_etime_hi and ac_etime_lo (24 bits)
*
* Format: 5 bit base 2 exponent, 20 bits mantissa.
* The leading bit of the mantissa is not stored, but implied for
@@ -348,15 +348,15 @@ static comp_t encode_comp_t(unsigned long value)
#define MANTSIZE2 20 /* 20 bit mantissa. */
#define EXPSIZE2 5 /* 5 bit base 2 exponent. */
-#define MAXFRACT2 ((1ul << MANTSIZE2) - 1) /* Maximum fractional value.
*/
-#define MAXEXP2 ((1 << EXPSIZE2) - 1) /* Maximum exponent. */
+#define MAXFRACT2 ((1 << MANTSIZE2) - 1) /* Maximum fractional value. */
+#define MAXEXP2 ((1 << EXPSIZE2) - 1) /* Maximum exponent. */
-static comp2_t encode_comp2_t(u64 value)
+static void encode_ac_etime_hilo(u64 value, acct_t *ac)
{
- int exp, rnd;
+ int exp = (value > (MAXFRACT2 >> 1));
+ int rnd = 0;
+ u32 etime;
- exp = (value > (MAXFRACT2>>1));
- rnd = 0;
while (value > MAXFRACT2) {
rnd = value & 1;
value >>= 1;
@@ -373,10 +373,12 @@ static comp2_t encode_comp2_t(u64 value)
if (exp > MAXEXP2) {
/* Overflow. Return largest representable number instead. */
- return (1ul << (MANTSIZE2+EXPSIZE2-1)) - 1;
+ etime = (1 << (MANTSIZE2 + EXPSIZE2 - 1)) - 1;
} else {
- return (value & (MAXFRACT2>>1)) | (exp << (MANTSIZE2-1));
+ etime = (value & (MAXFRACT2 >> 1)) | (exp << (MANTSIZE2 - 1));
}
+ ac->ac_etime_hi = etime >> 16;
+ ac->ac_etime_lo = (u16) etime;
}
#endif
@@ -436,17 +438,12 @@ static void fill_ac(acct_t *ac)
(unsigned long) elapsed : (unsigned long) -1l);
#endif
#if ACCT_VERSION == 1 || ACCT_VERSION == 2
- {
- /* new enlarged etime field */
- comp2_t etime = encode_comp2_t(elapsed);
-
- ac->ac_etime_hi = etime >> 16;
- ac->ac_etime_lo = (u16) etime;
- }
+ /* new enlarged etime field */
+ encode_ac_etime_hilo(elapsed, ac);
#endif
do_div(elapsed, AHZ);
ac->ac_btime = get_seconds() - elapsed;
-#if ACCT_VERSION==2
+#if ACCT_VERSION == 2
ac->ac_ahz = AHZ;
#endif
--
1.9.3
