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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-03-15 20:49:47 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-03-15 20:49:47 +0300 |
| commit | 63724e9519a312d7d0b8767d0aeb53bc15a7fdd5 (patch) | |
| tree | 236a236c3090af7befc357012dacc780d3df4670 /include/linux | |
| parent | 97450311306e95e2feb87c088acd6af216a3b077 (diff) | |
| parent | 192d852129b1b7c4f0ddbab95d0de1efd5ee1405 (diff) | |
| download | linux-63724e9519a312d7d0b8767d0aeb53bc15a7fdd5.tar.xz | |
Merge tag 'sched-urgent-2026-03-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
"More MM-CID fixes, mostly fixing hangs/races:
- Fix CID hangs due to a race between concurrent forks
- Fix vfork()/CLONE_VM MMCID bug causing hangs
- Remove pointless preemption guard
- Fix CID task list walk performance regression on large systems
by removing the known-flaky and slow counting logic using
for_each_process_thread() in mm_cid_*fixup_tasks_to_cpus(), and
implementing a simple sched_mm_cid::node list instead"
* tag 'sched-urgent-2026-03-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/mmcid: Avoid full tasklist walks
sched/mmcid: Remove pointless preempt guard
sched/mmcid: Handle vfork()/CLONE_VM correctly
sched/mmcid: Prevent CID stalls due to concurrent forks
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/rseq_types.h | 6 | ||||
| -rw-r--r-- | include/linux/sched.h | 2 |
2 files changed, 5 insertions, 3 deletions
diff --git a/include/linux/rseq_types.h b/include/linux/rseq_types.h index da5fa6f40294..0b42045988db 100644 --- a/include/linux/rseq_types.h +++ b/include/linux/rseq_types.h @@ -133,10 +133,12 @@ struct rseq_data { }; * @active: MM CID is active for the task * @cid: The CID associated to the task either permanently or * borrowed from the CPU + * @node: Queued in the per MM MMCID list */ struct sched_mm_cid { unsigned int active; unsigned int cid; + struct hlist_node node; }; /** @@ -157,6 +159,7 @@ struct mm_cid_pcpu { * @work: Regular work to handle the affinity mode change case * @lock: Spinlock to protect against affinity setting which can't take @mutex * @mutex: Mutex to serialize forks and exits related to this mm + * @user_list: List of the MM CID users of a MM * @nr_cpus_allowed: The number of CPUs in the per MM allowed CPUs map. The map * is growth only. * @users: The number of tasks sharing this MM. Separate from mm::mm_users @@ -177,13 +180,14 @@ struct mm_mm_cid { raw_spinlock_t lock; struct mutex mutex; + struct hlist_head user_list; /* Low frequency modified */ unsigned int nr_cpus_allowed; unsigned int users; unsigned int pcpu_thrs; unsigned int update_deferred; -}____cacheline_aligned_in_smp; +} ____cacheline_aligned; #else /* CONFIG_SCHED_MM_CID */ struct mm_mm_cid { }; struct sched_mm_cid { }; diff --git a/include/linux/sched.h b/include/linux/sched.h index a7b4a980eb2f..5a5d3dbc9cdf 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2354,7 +2354,6 @@ static __always_inline void alloc_tag_restore(struct alloc_tag *tag, struct allo #ifdef CONFIG_SCHED_MM_CID void sched_mm_cid_before_execve(struct task_struct *t); void sched_mm_cid_after_execve(struct task_struct *t); -void sched_mm_cid_fork(struct task_struct *t); void sched_mm_cid_exit(struct task_struct *t); static __always_inline int task_mm_cid(struct task_struct *t) { @@ -2363,7 +2362,6 @@ static __always_inline int task_mm_cid(struct task_struct *t) #else static inline void sched_mm_cid_before_execve(struct task_struct *t) { } static inline void sched_mm_cid_after_execve(struct task_struct *t) { } -static inline void sched_mm_cid_fork(struct task_struct *t) { } static inline void sched_mm_cid_exit(struct task_struct *t) { } static __always_inline int task_mm_cid(struct task_struct *t) { |