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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2019-04-23 17:26:36 +0300
committerIngo Molnar <mingo@kernel.org>2019-06-03 12:49:37 +0300
commit3bd3706251ee8ab67e69d9340ac2abdca217e733 (patch)
tree4431aa630d095905d840ace6a0b86e266395f71a /arch/mips
parentf2c7c76c5d0a443053e94adb9f0918fa2fb85c3a (diff)
downloadlinux-3bd3706251ee8ab67e69d9340ac2abdca217e733.tar.xz
sched/core: Provide a pointer to the valid CPU mask
In commit: 4b53a3412d66 ("sched/core: Remove the tsk_nr_cpus_allowed() wrapper") the tsk_nr_cpus_allowed() wrapper was removed. There was not much difference in !RT but in RT we used this to implement migrate_disable(). Within a migrate_disable() section the CPU mask is restricted to single CPU while the "normal" CPU mask remains untouched. As an alternative implementation Ingo suggested to use: struct task_struct { const cpumask_t *cpus_ptr; cpumask_t cpus_mask; }; with t->cpus_ptr = &t->cpus_mask; In -RT we then can switch the cpus_ptr to: t->cpus_ptr = &cpumask_of(task_cpu(p)); in a migration disabled region. The rules are simple: - Code that 'uses' ->cpus_allowed would use the pointer. - Code that 'modifies' ->cpus_allowed would use the direct mask. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lkml.kernel.org/r/20190423142636.14347-1-bigeasy@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/mips')
-rw-r--r--arch/mips/include/asm/switch_to.h4
-rw-r--r--arch/mips/kernel/mips-mt-fpaff.c2
-rw-r--r--arch/mips/kernel/traps.c6
3 files changed, 6 insertions, 6 deletions
diff --git a/arch/mips/include/asm/switch_to.h b/arch/mips/include/asm/switch_to.h
index 0f813bb753c6..09cbe9042828 100644
--- a/arch/mips/include/asm/switch_to.h
+++ b/arch/mips/include/asm/switch_to.h
@@ -42,7 +42,7 @@ extern struct task_struct *ll_task;
* inline to try to keep the overhead down. If we have been forced to run on
* a "CPU" with an FPU because of a previous high level of FP computation,
* but did not actually use the FPU during the most recent time-slice (CU1
- * isn't set), we undo the restriction on cpus_allowed.
+ * isn't set), we undo the restriction on cpus_mask.
*
* We're not calling set_cpus_allowed() here, because we have no need to
* force prompt migration - we're already switching the current CPU to a
@@ -57,7 +57,7 @@ do { \
test_ti_thread_flag(__prev_ti, TIF_FPUBOUND) && \
(!(KSTK_STATUS(prev) & ST0_CU1))) { \
clear_ti_thread_flag(__prev_ti, TIF_FPUBOUND); \
- prev->cpus_allowed = prev->thread.user_cpus_allowed; \
+ prev->cpus_mask = prev->thread.user_cpus_allowed; \
} \
next->thread.emulated_fp = 0; \
} while(0)
diff --git a/arch/mips/kernel/mips-mt-fpaff.c b/arch/mips/kernel/mips-mt-fpaff.c
index a7c0f97e4b0d..1a08428eedcf 100644
--- a/arch/mips/kernel/mips-mt-fpaff.c
+++ b/arch/mips/kernel/mips-mt-fpaff.c
@@ -177,7 +177,7 @@ asmlinkage long mipsmt_sys_sched_getaffinity(pid_t pid, unsigned int len,
if (retval)
goto out_unlock;
- cpumask_or(&allowed, &p->thread.user_cpus_allowed, &p->cpus_allowed);
+ cpumask_or(&allowed, &p->thread.user_cpus_allowed, p->cpus_ptr);
cpumask_and(&mask, &allowed, cpu_active_mask);
out_unlock:
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index c52766a5b85f..ac7159263da0 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -891,12 +891,12 @@ static void mt_ase_fp_affinity(void)
* restricted the allowed set to exclude any CPUs with FPUs,
* we'll skip the procedure.
*/
- if (cpumask_intersects(&current->cpus_allowed, &mt_fpu_cpumask)) {
+ if (cpumask_intersects(&current->cpus_mask, &mt_fpu_cpumask)) {
cpumask_t tmask;
current->thread.user_cpus_allowed
- = current->cpus_allowed;
- cpumask_and(&tmask, &current->cpus_allowed,
+ = current->cpus_mask;
+ cpumask_and(&tmask, &current->cpus_mask,
&mt_fpu_cpumask);
set_cpus_allowed_ptr(current, &tmask);
set_thread_flag(TIF_FPUBOUND);