Messages in this thread Patch in this message | | | Subject | Re: [rfc/patch] mm/slub: restore/expand unfreeze_partials() local exclusion scope | From | Mike Galbraith <> | Date | Wed, 21 Jul 2021 11:33:41 +0200 |
| |
On Wed, 2021-07-21 at 10:44 +0200, Vlastimil Babka wrote: > > So this doesn't look like our put_cpu_partial() preempted a > __slab_alloc() on the same cpu, right?
No, likely it was the one preempted by someone long gone, but we'll never know without setting a trap.
> BTW did my ugly patch work?
Nope. I guess you missed my reporting it to have been a -ENOBOOT, and that cutting it in half, ie snagging only __slab_free() does boot, and seems to cure all of the RT fireworks.
(chainsaw noises...)
--- mm/slub.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)
--- a/mm/slub.c +++ b/mm/slub.c @@ -2551,6 +2551,8 @@ static void put_cpu_partial(struct kmem_ int pobjects;
slub_get_cpu_ptr(s->cpu_slab); + if (IS_ENABLED(CONFIG_PREEMPT_RT) && drain) + local_lock(&s->cpu_slab->lock); do { pages = 0; pobjects = 0; @@ -2564,7 +2566,13 @@ static void put_cpu_partial(struct kmem_ * partial array is full. Move the existing * set to the per node partial list. */ - unfreeze_partials(s); + this_cpu_write(s->cpu_slab->partial, NULL); + if (IS_ENABLED(CONFIG_PREEMPT_RT) && drain) + local_unlock(&s->cpu_slab->lock); + __unfreeze_partials(s, oldpage); + if (IS_ENABLED(CONFIG_PREEMPT_RT) && drain) + local_lock(&s->cpu_slab->lock); + oldpage = NULL; pobjects = 0; pages = 0; @@ -2581,6 +2589,8 @@ static void put_cpu_partial(struct kmem_
} while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) != oldpage); + if (IS_ENABLED(CONFIG_PREEMPT_RT) && drain) + local_unlock(&s->cpu_slab->lock); slub_put_cpu_ptr(s->cpu_slab); #endif /* CONFIG_SLUB_CPU_PARTIAL */ }
| |