From 3afb00d3f86d3d924f88b56fa8285d4e9db85852 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 7 Aug 2024 15:17:52 +0200 Subject: Merging upstream version 6.10.3. Signed-off-by: Daniel Baumann --- kernel/time/timer_migration.h | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'kernel/time/timer_migration.h') diff --git a/kernel/time/timer_migration.h b/kernel/time/timer_migration.h index 6c37d94a37..494f68cc13 100644 --- a/kernel/time/timer_migration.h +++ b/kernel/time/timer_migration.h @@ -22,7 +22,17 @@ struct tmigr_event { * struct tmigr_group - timer migration hierarchy group * @lock: Lock protecting the event information and group hierarchy * information during setup - * @parent: Pointer to the parent group + * @parent: Pointer to the parent group. Pointer is updated when a + * new hierarchy level is added because of a CPU coming + * online the first time. Once it is set, the pointer will + * not be removed or updated. When accessing parent pointer + * lock less to decide whether to abort a propagation or + * not, it is not a problem. The worst outcome is an + * unnecessary/early CPU wake up. But do not access parent + * pointer several times in the same 'action' (like + * activation, deactivation, check for remote expiry,...) + * without holding the lock as it is not ensured that value + * will not change. * @groupevt: Next event of the group which is only used when the * group is !active. The group event is then queued into * the parent timer queue. -- cgit v1.2.3