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author | Xie Xiaobo <xiaobo.xie@nxp.com> | 2017-12-12 08:12:33 (GMT) |
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committer | Xie Xiaobo <xiaobo.xie@nxp.com> | 2017-12-12 08:12:33 (GMT) |
commit | c0246a9ec4d461ef4dd7647f94005380bb9e7f0b (patch) | |
tree | 7588601aa6ce98f5e9fd083a1b351d9023c0b295 /include/linux/cpuset.h | |
parent | 50fd1a6d79d48a7c35890aecce5a5d6b872a461d (diff) | |
parent | 56f4a560c6d6318b5a8e18a1b3e44909a5158d1e (diff) | |
download | linux-c0246a9ec4d461ef4dd7647f94005380bb9e7f0b.tar.xz |
Merge Linaro linux 4.9.62 into linux-4.9
Signed-off-by: Xiaobo Xie <xiaobo.xie@nxp.com>
Diffstat (limited to 'include/linux/cpuset.h')
-rw-r--r-- | include/linux/cpuset.h | 25 |
1 files changed, 23 insertions, 2 deletions
diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h index bfc204e..d807fa9 100644 --- a/include/linux/cpuset.h +++ b/include/linux/cpuset.h @@ -16,6 +16,19 @@ #ifdef CONFIG_CPUSETS +/* + * Static branch rewrites can happen in an arbitrary order for a given + * key. In code paths where we need to loop with read_mems_allowed_begin() and + * read_mems_allowed_retry() to get a consistent view of mems_allowed, we need + * to ensure that begin() always gets rewritten before retry() in the + * disabled -> enabled transition. If not, then if local irqs are disabled + * around the loop, we can deadlock since retry() would always be + * comparing the latest value of the mems_allowed seqcount against 0 as + * begin() still would see cpusets_enabled() as false. The enabled -> disabled + * transition should happen in reverse order for the same reasons (want to stop + * looking at real value of mems_allowed.sequence in retry() first). + */ +extern struct static_key_false cpusets_pre_enable_key; extern struct static_key_false cpusets_enabled_key; static inline bool cpusets_enabled(void) { @@ -30,17 +43,21 @@ static inline int nr_cpusets(void) static inline void cpuset_inc(void) { + static_branch_inc(&cpusets_pre_enable_key); static_branch_inc(&cpusets_enabled_key); } static inline void cpuset_dec(void) { static_branch_dec(&cpusets_enabled_key); + static_branch_dec(&cpusets_pre_enable_key); } extern int cpuset_init(void); extern void cpuset_init_smp(void); +extern void cpuset_force_rebuild(void); extern void cpuset_update_active_cpus(bool cpu_online); +extern void cpuset_wait_for_hotplug(void); extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask); extern void cpuset_cpus_allowed_fallback(struct task_struct *p); extern nodemask_t cpuset_mems_allowed(struct task_struct *p); @@ -113,7 +130,7 @@ extern void cpuset_print_current_mems_allowed(void); */ static inline unsigned int read_mems_allowed_begin(void) { - if (!cpusets_enabled()) + if (!static_branch_unlikely(&cpusets_pre_enable_key)) return 0; return read_seqcount_begin(¤t->mems_allowed_seq); @@ -127,7 +144,7 @@ static inline unsigned int read_mems_allowed_begin(void) */ static inline bool read_mems_allowed_retry(unsigned int seq) { - if (!cpusets_enabled()) + if (!static_branch_unlikely(&cpusets_enabled_key)) return false; return read_seqcount_retry(¤t->mems_allowed_seq, seq); @@ -153,11 +170,15 @@ static inline bool cpusets_enabled(void) { return false; } static inline int cpuset_init(void) { return 0; } static inline void cpuset_init_smp(void) {} +static inline void cpuset_force_rebuild(void) { } + static inline void cpuset_update_active_cpus(bool cpu_online) { partition_sched_domains(1, NULL, NULL); } +static inline void cpuset_wait_for_hotplug(void) { } + static inline void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask) { |