Messages in this thread | | | From | KOSAKI Motohiro <> | Subject | Re: [RFC 6/8] In order putback lru core | Date | Sun, 1 May 2011 22:47:11 +0900 (JST) |
| |
> > +/* This structure is used for keeping LRU ordering of isolated page */ > > +struct pages_lru { > > + struct page *page; /* isolated page */ > > + struct page *prev_page; /* previous page of isolate page as LRU order */ > > + struct page *next_page; /* next page of isolate page as LRU order */ > > + struct list_head lru; > > +}; > > /* > > So this thing has to be allocated from somewhere. We can't put it > on the stack as we're already in danger there so we must be using > kmalloc. In the reclaim paths, this should be avoided obviously. > For compaction, we might hurt the compaction success rates if pages > are pinned with control structures. It's something to be wary of. > > At LSF/MM, I stated a preference for swapping the source and > destination pages in the LRU. This unfortunately means that the LRU > now contains a page in the process of being migrated to and the backout > paths for migration failure become a lot more complex. Reclaim should > be ok as it'll should fail to lock the page and recycle it in the list. > This avoids allocations but I freely admit that I'm not in the position > to implement such a thing right now :(
I like swaping to fake page. one way pointer might become dangerous. vmscan can detect fake page and ignore it.
ie, is_fake_page(page) { if (is_stack_addr((void*)page)) return true; return false; }
Also, I like to use stack rather than kmalloc in compaction.
| |