diff options
author | Arnd Bergmann <arnd@arndb.de> | 2015-11-25 16:16:55 +0100 |
---|---|---|
committer | Tejun Heo <tj@kernel.org> | 2015-11-25 14:00:05 -0500 |
commit | d2b4365809060b256330a99289de9797a5dd6967 (patch) | |
tree | 9365cd0791b20332059ec044962314f152ff4c46 /kernel/cpuset.c | |
parent | 6c2920926b10e8303378408e3c2b8952071d4344 (diff) | |
download | lwn-d2b4365809060b256330a99289de9797a5dd6967.tar.gz lwn-d2b4365809060b256330a99289de9797a5dd6967.zip |
cpuset: Replace all instances of time_t with time64_t
The following patch replaces all instances of time_t with time64_t i.e.
change the type used for representing time from 32-bit to 64-bit. All
32-bit kernels to date use a signed 32-bit time_t type, which can only
represent time until January 2038. Since embedded systems running 32-bit
Linux are going to survive beyond that date, we have to change all
current uses, in a backwards compatible way.
The patch also changes the function get_seconds() that returns a 32-bit
integer to ktime_get_seconds() that returns seconds as 64-bit integer.
The patch changes the type of ticks from time_t to u32. We keep ticks as
32-bits as the function uses 32-bit arithmetic which would prove less
expensive than 64-bit arithmetic and the function is expected to be
called atleast once every 32 seconds.
Signed-off-by: Heena Sirwani <heenasirwani@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/cpuset.c')
-rw-r--r-- | kernel/cpuset.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/kernel/cpuset.c b/kernel/cpuset.c index 10ae73611d80..c9ea63ff70a7 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -51,6 +51,7 @@ #include <linux/stat.h> #include <linux/string.h> #include <linux/time.h> +#include <linux/time64.h> #include <linux/backing-dev.h> #include <linux/sort.h> @@ -68,7 +69,7 @@ struct static_key cpusets_enabled_key __read_mostly = STATIC_KEY_INIT_FALSE; struct fmeter { int cnt; /* unprocessed events count */ int val; /* most recent output value */ - time_t time; /* clock (secs) when val computed */ + time64_t time; /* clock (secs) when val computed */ spinlock_t lock; /* guards read or write of above */ }; @@ -1374,7 +1375,7 @@ out: */ #define FM_COEF 933 /* coefficient for half-life of 10 secs */ -#define FM_MAXTICKS ((time_t)99) /* useless computing more ticks than this */ +#define FM_MAXTICKS ((u32)99) /* useless computing more ticks than this */ #define FM_MAXCNT 1000000 /* limit cnt to avoid overflow */ #define FM_SCALE 1000 /* faux fixed point scale */ @@ -1390,8 +1391,11 @@ static void fmeter_init(struct fmeter *fmp) /* Internal meter update - process cnt events and update value */ static void fmeter_update(struct fmeter *fmp) { - time_t now = get_seconds(); - time_t ticks = now - fmp->time; + time64_t now; + u32 ticks; + + now = ktime_get_seconds(); + ticks = now - fmp->time; if (ticks == 0) return; |