Messages in this thread | | | Date | Tue, 12 Mar 2019 04:35:15 +0000 | From | Christopher Lameter <> | Subject | Re: [RFC 02/15] slub: Add isolate() and migrate() methods |
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On Mon, 11 Mar 2019, Roman Gushchin wrote:
> > --- a/mm/slub.c > > +++ b/mm/slub.c > > @@ -4325,6 +4325,34 @@ int __kmem_cache_create(struct kmem_cache *s, slab_flags_t flags) > > return err; > > } > > > > +void kmem_cache_setup_mobility(struct kmem_cache *s, > > + kmem_cache_isolate_func isolate, > > + kmem_cache_migrate_func migrate) > > +{ > > I wonder if it's better to adapt kmem_cache_create() to take two additional > argument? I suspect mobility is not a dynamic option, so it can be > set on kmem_cache creation.
One other idea that prior versions of this patchset used was to change kmem_cache_create() so that the ctor parameter becomes an ops vector.
However, in order to reduce the size of the patchset I dropped that. It could be easily moved back to the way it was before.
> > + /* > > + * Sadly serialization requirements currently mean that we have > > + * to disable fast cmpxchg based processing. > > + */ > > Can you, please, elaborate a bit more here?
cmpxchg based processing does not lock the struct page. SMO requires to ensure that all changes on a slab page can be stopped. The page->lock will accomplish that. I think we could avoid dealing with actually locking the page with some more work.
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