Displaying 5 results from an estimated 5 matches for "llist_for_each_safe".
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list_for_each_safe
2023 May 23
4
[PATCH 3/3] fork, vhost: Use CLONE_THREAD to fix freezer/ps regression
...ry_safe(work, work_next, node, node) {
clear_bit(VHOST_WORK_QUEUED, &work->flags);
I am not sure about smp_wmb + clear_bit. Once we clear VHOST_WORK_QUEUED,
vhost_work_queue() can add this work again and change work->node->next.
That is why we use _safe, but we need to ensure that llist_for_each_safe()
completes LOAD(work->node->next) before VHOST_WORK_QUEUED is cleared.
So it seems that smp_wmb() can't help and should be removed, instead we need
llist_for_each_entry_safe(...) {
smp_mb__before_atomic();
clear_bit(VHOST_WORK_QUEUED, &work->flags);
Also, if the work-&g...
2023 May 31
1
[PATCH 3/3] fork, vhost: Use CLONE_THREAD to fix freezer/ps regression
...t; > > >
> > > >I am not sure about smp_wmb + clear_bit. Once we clear VHOST_WORK_QUEUED,
> > > >vhost_work_queue() can add this work again and change work->node->next.
> > > >
> > > >That is why we use _safe, but we need to ensure that llist_for_each_safe()
> > > >completes LOAD(work->node->next) before VHOST_WORK_QUEUED is cleared.
> > >
> > > This should be fine since store is not speculated, so work->node->next needs
> > > to be loaded before VHOST_WORK_QUEUED is cleared to meet the loop conditio...
2023 May 22
1
[PATCH 3/3] fork, vhost: Use CLONE_THREAD to fix freezer/ps regression
On 05/22, Mike Christie wrote:
>
> On 5/22/23 7:30 AM, Oleg Nesterov wrote:
> >> + /*
> >> + * When we get a SIGKILL our release function will
> >> + * be called. That will stop new IOs from being queued
> >> + * and check for outstanding cmd responses. It will then
> >> + * call vhost_task_stop to tell us to return and exit.
>
2023 May 23
2
[PATCH 3/3] fork, vhost: Use CLONE_THREAD to fix freezer/ps regression
...e, node) {
> clear_bit(VHOST_WORK_QUEUED, &work->flags);
>
> I am not sure about smp_wmb + clear_bit. Once we clear VHOST_WORK_QUEUED,
> vhost_work_queue() can add this work again and change work->node->next.
>
> That is why we use _safe, but we need to ensure that llist_for_each_safe()
> completes LOAD(work->node->next) before VHOST_WORK_QUEUED is cleared.
>
> So it seems that smp_wmb() can't help and should be removed, instead we need
>
> llist_for_each_entry_safe(...) {
> smp_mb__before_atomic();
> clear_bit(VHOST_WORK_QUEUED, &work-...
2023 Jun 01
1
[PATCH 3/3] fork, vhost: Use CLONE_THREAD to fix freezer/ps regression
...t; > > > >I am not sure about smp_wmb + clear_bit. Once we clear VHOST_WORK_QUEUED,
> > > > >vhost_work_queue() can add this work again and change work->node->next.
> > > > >
> > > > >That is why we use _safe, but we need to ensure that llist_for_each_safe()
> > > > >completes LOAD(work->node->next) before VHOST_WORK_QUEUED is cleared.
> > > >
> > > > This should be fine since store is not speculated, so work->node->next needs
> > > > to be loaded before VHOST_WORK_QUEUED is cleared to me...