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| author | Jason Gunthorpe | 2019-07-02 19:34:43 +0200 |
|---|---|---|
| committer | Jason Gunthorpe | 2019-07-02 19:34:43 +0200 |
| commit | 9ec3f4cb35bc8278f0582fed9f9229c9315c2ffb (patch) | |
| tree | 3ff6a17a33913268a2ed06e7d9a1a95e29eeee97 /include/linux/cgroup.h | |
| parent | mm/swap: fix release_pages() when releasing devmap pages (diff) | |
| parent | Linux 5.2-rc7 (diff) | |
| download | kernel-qcow2-linux-9ec3f4cb35bc8278f0582fed9f9229c9315c2ffb.tar.gz kernel-qcow2-linux-9ec3f4cb35bc8278f0582fed9f9229c9315c2ffb.tar.xz kernel-qcow2-linux-9ec3f4cb35bc8278f0582fed9f9229c9315c2ffb.zip | |
Merge tag 'v5.2-rc7' into rdma.git hmm
Required for dependencies in the next patches.
Diffstat (limited to 'include/linux/cgroup.h')
| -rw-r--r-- | include/linux/cgroup.h | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index c0077adeea83..0297f930a56e 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -43,6 +43,9 @@ /* walk all threaded css_sets in the domain */ #define CSS_TASK_ITER_THREADED (1U << 1) +/* internal flags */ +#define CSS_TASK_ITER_SKIPPED (1U << 16) + /* a css_task_iter should be treated as an opaque object */ struct css_task_iter { struct cgroup_subsys *ss; @@ -57,6 +60,7 @@ struct css_task_iter { struct list_head *task_pos; struct list_head *tasks_head; struct list_head *mg_tasks_head; + struct list_head *dying_tasks_head; struct css_set *cur_cset; struct css_set *cur_dcset; @@ -487,7 +491,7 @@ static inline struct cgroup_subsys_state *task_css(struct task_struct *task, * * Find the css for the (@task, @subsys_id) combination, increment a * reference on and return it. This function is guaranteed to return a - * valid css. + * valid css. The returned css may already have been offlined. */ static inline struct cgroup_subsys_state * task_get_css(struct task_struct *task, int subsys_id) @@ -497,7 +501,13 @@ task_get_css(struct task_struct *task, int subsys_id) rcu_read_lock(); while (true) { css = task_css(task, subsys_id); - if (likely(css_tryget_online(css))) + /* + * Can't use css_tryget_online() here. A task which has + * PF_EXITING set may stay associated with an offline css. + * If such task calls this function, css_tryget_online() + * will keep failing. + */ + if (likely(css_tryget(css))) break; cpu_relax(); } |