diff options
| author | Chen Ridong <chenridong@huawei.com> | 2025-08-13 08:29:01 +0000 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2025-08-13 08:14:20 -1000 |
| commit | 4c70fb2624ab1588faa58dcd407d4c61d64b288d (patch) | |
| tree | 8e7f07a5ee8568d13ee5bfa15b1d4e72ffe0fb8c /kernel | |
| parent | cgroup: Replace deprecated strcpy() with strscpy() (diff) | |
| download | linux-4c70fb2624ab1588faa58dcd407d4c61d64b288d.tar.gz linux-4c70fb2624ab1588faa58dcd407d4c61d64b288d.zip | |
cpuset: remove redundant CS_ONLINE flag
The CS_ONLINE flag was introduced prior to the CSS_ONLINE flag in the
cpuset subsystem. Currently, the flag setting sequence is as follows:
1. cpuset_css_online() sets CS_ONLINE
2. css->flags gets CSS_ONLINE set
...
3. cgroup->kill_css sets CSS_DYING
4. cpuset_css_offline() clears CS_ONLINE
5. css->flags clears CSS_ONLINE
The is_cpuset_online() check currently occurs between steps 1 and 3.
However, it would be equally safe to perform this check between steps 2
and 3, as CSS_ONLINE provides the same synchronization guarantee as
CS_ONLINE.
Since CS_ONLINE is redundant with CSS_ONLINE and provides no additional
synchronization benefits, we can safely remove it to simplify the code.
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/cgroup/cpuset-internal.h | 3 | ||||
| -rw-r--r-- | kernel/cgroup/cpuset.c | 4 |
2 files changed, 2 insertions, 5 deletions
diff --git a/kernel/cgroup/cpuset-internal.h b/kernel/cgroup/cpuset-internal.h index 383963e28ac6..75b3aef39231 100644 --- a/kernel/cgroup/cpuset-internal.h +++ b/kernel/cgroup/cpuset-internal.h @@ -38,7 +38,6 @@ enum prs_errcode { /* bits in struct cpuset flags field */ typedef enum { - CS_ONLINE, CS_CPU_EXCLUSIVE, CS_MEM_EXCLUSIVE, CS_MEM_HARDWALL, @@ -202,7 +201,7 @@ static inline struct cpuset *parent_cs(struct cpuset *cs) /* convenient tests for these bits */ static inline bool is_cpuset_online(struct cpuset *cs) { - return test_bit(CS_ONLINE, &cs->flags) && !css_is_dying(&cs->css); + return css_is_online(&cs->css) && !css_is_dying(&cs->css); } static inline int is_cpu_exclusive(const struct cpuset *cs) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 27adb04df675..3466ebbf1016 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -207,7 +207,7 @@ static inline void notify_partition_change(struct cpuset *cs, int old_prs) * parallel, we may leave an offline CPU in cpu_allowed or some other masks. */ static struct cpuset top_cpuset = { - .flags = BIT(CS_ONLINE) | BIT(CS_CPU_EXCLUSIVE) | + .flags = BIT(CS_CPU_EXCLUSIVE) | BIT(CS_MEM_EXCLUSIVE) | BIT(CS_SCHED_LOAD_BALANCE), .partition_root_state = PRS_ROOT, .relax_domain_level = -1, @@ -3496,7 +3496,6 @@ static int cpuset_css_online(struct cgroup_subsys_state *css) cpus_read_lock(); mutex_lock(&cpuset_mutex); - set_bit(CS_ONLINE, &cs->flags); if (is_spread_page(parent)) set_bit(CS_SPREAD_PAGE, &cs->flags); if (is_spread_slab(parent)) @@ -3571,7 +3570,6 @@ static void cpuset_css_offline(struct cgroup_subsys_state *css) cpuset_update_flag(CS_SCHED_LOAD_BALANCE, cs, 0); cpuset_dec(); - clear_bit(CS_ONLINE, &cs->flags); mutex_unlock(&cpuset_mutex); cpus_read_unlock(); |