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Subject[tip: timers/core] posix-cpu-timers: Deduplicate rlimit handling
The following commit has been merged into the timers/core branch of tip:

Commit-ID: 8991afe2640d05a805eba01277856e8549cdc838
Gitweb: https://git.kernel.org/tip/8991afe2640d05a805eba01277856e8549cdc838
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Wed, 21 Aug 2019 21:09:23 +02:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Wed, 28 Aug 2019 11:50:42 +02:00

posix-cpu-timers: Deduplicate rlimit handling

Both thread and process expiry functions have the same functionality for
sending signals for soft and hard RLIMITs duplicated in 4 different
ways.

Split it out into a common function and cleanup the callsites.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192922.653276779@linutronix.de

---
kernel/time/posix-cpu-timers.c | 67 ++++++++++++---------------------
1 file changed, 25 insertions(+), 42 deletions(-)

diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index 115c8df..ef39a7a 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -772,6 +772,20 @@ static inline void check_dl_overrun(struct task_struct *tsk)
}
}

+static bool check_rlimit(u64 time, u64 limit, int signo, bool rt, bool hard)
+{
+ if (time < limit)
+ return false;
+
+ if (print_fatal_signals) {
+ pr_info("%s Watchdog Timeout (%s): %s[%d]\n",
+ rt ? "RT" : "CPU", hard ? "hard" : "soft",
+ current->comm, task_pid_nr(current));
+ }
+ __group_send_sig_info(signo, SEND_SIG_PRIV, current);
+ return true;
+}
+
/*
* Check for any per-thread CPU timers that have fired and move them off
* the tsk->cpu_timers[N] list onto the firing list. Here we update the
@@ -799,34 +813,18 @@ static void check_thread_timers(struct task_struct *tsk,
soft = task_rlimit(tsk, RLIMIT_RTTIME);
if (soft != RLIM_INFINITY) {
/* Task RT timeout is accounted in jiffies. RTTIME is usec */
- unsigned long rtim = tsk->rt.timeout * (USEC_PER_SEC / HZ);
+ unsigned long rttime = tsk->rt.timeout * (USEC_PER_SEC / HZ);
unsigned long hard = task_rlimit_max(tsk, RLIMIT_RTTIME);

- if (hard != RLIM_INFINITY && rtim >= hard) {
- /*
- * At the hard limit, we just die.
- * No need to calculate anything else now.
- */
- if (print_fatal_signals) {
- pr_info("CPU Watchdog Timeout (hard): %s[%d]\n",
- tsk->comm, task_pid_nr(tsk));
- }
- __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
+ /* At the hard limit, send SIGKILL. No further action. */
+ if (hard != RLIM_INFINITY &&
+ check_rlimit(rttime, hard, SIGKILL, true, true))
return;
- }

- if (rtim >= soft) {
- /*
- * At the soft limit, send a SIGXCPU every second.
- */
+ /* At the soft limit, send a SIGXCPU every second */
+ if (check_rlimit(rttime, soft, SIGXCPU, true, false)) {
soft += USEC_PER_SEC;
tsk->signal->rlim[RLIMIT_RTTIME].rlim_cur = soft;
-
- if (print_fatal_signals) {
- pr_info("RT Watchdog Timeout (soft): %s[%d]\n",
- tsk->comm, task_pid_nr(tsk));
- }
- __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
}
}

@@ -916,28 +914,13 @@ static void check_process_timers(struct task_struct *tsk,
u64 softns = (u64)soft * NSEC_PER_SEC;
u64 hardns = (u64)hard * NSEC_PER_SEC;

- if (hard != RLIM_INFINITY && ptime >= hardns) {
- /*
- * At the hard limit, we just die.
- * No need to calculate anything else now.
- */
- if (print_fatal_signals) {
- pr_info("RT Watchdog Timeout (hard): %s[%d]\n",
- tsk->comm, task_pid_nr(tsk));
- }
- __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
+ /* At the hard limit, send SIGKILL. No further action. */
+ if (hard != RLIM_INFINITY &&
+ check_rlimit(ptime, hardns, SIGKILL, false, true))
return;
- }
- if (ptime >= softns) {
- /*
- * At the soft limit, send a SIGXCPU every second.
- */
- if (print_fatal_signals) {
- pr_info("CPU Watchdog Timeout (soft): %s[%d]\n",
- tsk->comm, task_pid_nr(tsk));
- }
- __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);

+ /* At the soft limit, send a SIGXCPU every second */
+ if (check_rlimit(ptime, softns, SIGXCPU, false, false)) {
sig->rlim[RLIMIT_CPU].rlim_cur = soft + 1;
softns += NSEC_PER_SEC;
}
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