diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2019-08-21 21:09:07 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2019-08-28 11:50:35 +0200 |
| commit | 11b8462f7e1d25f639c88949a2746a9c2667a766 (patch) | |
| tree | 5d811cd589e5ac6187a91f6773c8d4819dac5d0e /kernel/time | |
| parent | 3a245c0f110e2bfcf7f2cd2248a29005c78999e3 (diff) | |
posix-cpu-timers: Provide array based access to expiry cache
Using struct task_cputime for the expiry cache is a pretty odd choice and
comes with magic defines to rename the fields for usage in the expiry
cache.
struct task_cputime is basically a u64 array with 3 members, but it has
distinct members.
The expiry cache content is different than the content of task_cputime
because
expiry[PROF] = task_cputime.stime + task_cputime.utime
expiry[VIRT] = task_cputime.utime
expiry[SCHED] = task_cputime.sum_exec_runtime
So there is no direct mapping between task_cputime and the expiry cache and
the #define based remapping is just a horrible hack.
Having the expiry cache array based allows further simplification of the
expiry code.
To avoid an all in one cleanup which is hard to review add a temporary
anonymous union into struct task_cputime which allows array based access to
it. That requires to reorder the members. Add a build time sanity check to
validate that the members are at the same place.
The union and the build time checks will be removed after conversion.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192921.105793824@linutronix.de
Diffstat (limited to 'kernel/time')
| -rw-r--r-- | kernel/time/posix-cpu-timers.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c index 3e29d1692437..a38b6d04e8b5 100644 --- a/kernel/time/posix-cpu-timers.c +++ b/kernel/time/posix-cpu-timers.c @@ -18,13 +18,23 @@ #include "posix-timers.h" +static inline void temporary_check(void) +{ + BUILD_BUG_ON(offsetof(struct task_cputime, stime) != + CPUCLOCK_PROF * sizeof(u64)); + BUILD_BUG_ON(offsetof(struct task_cputime, utime) != + CPUCLOCK_VIRT * sizeof(u64)); + BUILD_BUG_ON(offsetof(struct task_cputime, sum_exec_runtime) != + CPUCLOCK_SCHED * sizeof(u64)); +} + static void posix_cpu_timer_rearm(struct k_itimer *timer); void posix_cputimers_group_init(struct posix_cputimers *pct, u64 cpu_limit) { posix_cputimers_init(pct); if (cpu_limit != RLIM_INFINITY) - pct->cputime_expires.prof_exp = cpu_limit * NSEC_PER_SEC; + pct->expiries[CPUCLOCK_PROF] = cpu_limit * NSEC_PER_SEC; } /* |