diff options
| author | Ben Hutchings <ben@decadent.org.uk> | 2019-05-10 00:46:25 +0100 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2019-05-22 23:15:13 +0100 |
| commit | b772b1dd9a3718dc565039b5953793c71713b9c6 (patch) | |
| tree | 8fb48c52f4ae5eaea5850a293e59dcd292dc8c78 /kernel | |
| parent | 9c18f59d9daddc8c6090bb0f1d60bcb6e320deb9 (diff) | |
sched: Add sched_smt_active()
Add the sched_smt_active() function needed for some x86 speculation
mitigations. This was introduced upstream by commits 1b568f0aabf2
"sched/core: Optimize SCHED_SMT", ba2591a5993e "sched/smt: Update
sched_smt_present at runtime", c5511d03ec09 "sched/smt: Make
sched_smt_present track topology", and 321a874a7ef8 "sched/smt: Expose
sched_smt_present static key". The upstream implementation uses the
static_key_{disable,enable}_cpuslocked() functions, which aren't
practical to backport.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/core.c | 19 | ||||
| -rw-r--r-- | kernel/sched/sched.h | 1 |
2 files changed, 20 insertions, 0 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index abda0a8493c5..45dd606138b0 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5210,6 +5210,10 @@ static void __cpuinit set_cpu_rq_start_time(void) rq->age_stamp = sched_clock_cpu(cpu); } +#ifdef CONFIG_SCHED_SMT +atomic_t sched_smt_present = ATOMIC_INIT(0); +#endif + static int sched_cpu_active(struct notifier_block *nfb, unsigned long action, void *hcpu) { @@ -5226,6 +5230,13 @@ static int sched_cpu_active(struct notifier_block *nfb, * Thus, fall-through and help the starting CPU along. */ case CPU_DOWN_FAILED: +#ifdef CONFIG_SCHED_SMT + /* + * When going up, increment the number of cores with SMT present. + */ + if (cpumask_weight(cpu_smt_mask((long)hcpu)) == 2) + atomic_inc(&sched_smt_present); +#endif set_cpu_active((long)hcpu, true); return NOTIFY_OK; default: @@ -5243,6 +5254,14 @@ static int sched_cpu_inactive(struct notifier_block *nfb, case CPU_DOWN_PREPARE: set_cpu_active(cpu, false); +#ifdef CONFIG_SCHED_SMT + /* + * When going down, decrement the number of cores with SMT present. + */ + if (cpumask_weight(cpu_smt_mask(cpu)) == 2) + atomic_dec(&sched_smt_present); +#endif + /* explicitly allow suspend */ if (!(action & CPU_TASKS_FROZEN)) { struct dl_bw *dl_b = dl_bw_of(cpu); diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index e7e841393443..41e3547263d4 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2,6 +2,7 @@ #include <linux/sched.h> #include <linux/sched/sysctl.h> #include <linux/sched/rt.h> +#include <linux/sched/smt.h> #include <linux/sched/deadline.h> #include <linux/mutex.h> #include <linux/spinlock.h> |