On 05/06/2010 03:40 PM, Rafael J. Wysocki wrote: > On Saturday 01 May 2010, Oren Laadan wrote: >> From: Matt Helsley <matthltc@xxxxxxxxxx> >> >> Update stale comments regarding locking order and add a little more detail >> so it's easier to follow the locking between the cgroup freezer and the >> power management freezer code. > > I guess these three patches are for me. > > Do you want me to handle them? Yes, please, that would be great. Thanks, Oren. > > Rafael > > >> Signed-off-by: Matt Helsley <matthltc@xxxxxxxxxx> >> Cc: Oren Laadan <orenl@xxxxxxxxxxxxxxx> >> Cc: Cedric Le Goater <legoater@xxxxxxx> >> Cc: Paul Menage <menage@xxxxxxxxxx> >> Cc: Li Zefan <lizf@xxxxxxxxxxxxxx> >> Cc: Rafael J. Wysocki <rjw@xxxxxxx> >> Cc: linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx >> --- >> kernel/cgroup_freezer.c | 21 +++++++++++++-------- >> 1 files changed, 13 insertions(+), 8 deletions(-) >> >> diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c >> index da5e139..85f19cc 100644 >> --- a/kernel/cgroup_freezer.c >> +++ b/kernel/cgroup_freezer.c >> @@ -89,10 +89,10 @@ struct cgroup_subsys freezer_subsys; >> >> /* Locks taken and their ordering >> * ------------------------------ >> - * css_set_lock >> * cgroup_mutex (AKA cgroup_lock) >> - * task->alloc_lock (AKA task_lock) >> * freezer->lock >> + * css_set_lock >> + * task->alloc_lock (AKA task_lock) >> * task->sighand->siglock >> * >> * cgroup code forces css_set_lock to be taken before task->alloc_lock >> @@ -100,33 +100,38 @@ struct cgroup_subsys freezer_subsys; >> * freezer_create(), freezer_destroy(): >> * cgroup_mutex [ by cgroup core ] >> * >> - * can_attach(): >> - * cgroup_mutex >> + * freezer_can_attach(): >> + * cgroup_mutex (held by caller of can_attach) >> * >> - * cgroup_frozen(): >> + * cgroup_freezing_or_frozen(): >> * task->alloc_lock (to get task's cgroup) >> * >> * freezer_fork() (preserving fork() performance means can't take cgroup_mutex): >> - * task->alloc_lock (to get task's cgroup) >> * freezer->lock >> * sighand->siglock (if the cgroup is freezing) >> * >> * freezer_read(): >> * cgroup_mutex >> * freezer->lock >> + * write_lock css_set_lock (cgroup iterator start) >> + * task->alloc_lock >> * read_lock css_set_lock (cgroup iterator start) >> * >> * freezer_write() (freeze): >> * cgroup_mutex >> * freezer->lock >> + * write_lock css_set_lock (cgroup iterator start) >> + * task->alloc_lock >> * read_lock css_set_lock (cgroup iterator start) >> - * sighand->siglock >> + * sighand->siglock (fake signal delivery inside freeze_task()) >> * >> * freezer_write() (unfreeze): >> * cgroup_mutex >> * freezer->lock >> + * write_lock css_set_lock (cgroup iterator start) >> + * task->alloc_lock >> * read_lock css_set_lock (cgroup iterator start) >> - * task->alloc_lock (to prevent races with freeze_task()) >> + * task->alloc_lock (inside thaw_process(), prevents race with refrigerator()) >> * sighand->siglock >> */ >> static struct cgroup_subsys_state *freezer_create(struct cgroup_subsys *ss, >> > > _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
