Messages in this thread | | | Date | Fri, 4 Dec 2015 21:43:02 +0800 | From | Geliang Tang <> | Subject | Re: [PATCH v2] mm/slab.c: use list_{empty_careful,last_entry} in drain_freelist |
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On Thu, Dec 03, 2015 at 08:53:21AM -0600, Christoph Lameter wrote: > On Thu, 3 Dec 2015, Geliang Tang wrote: > > > while (nr_freed < tofree && !list_empty(&n->slabs_free)) { > > > > spin_lock_irq(&n->list_lock); > > - p = n->slabs_free.prev; > > - if (p == &n->slabs_free) { > > + if (list_empty_careful(&n->slabs_free)) { > > We have taken the lock. Why do we need to be "careful"? list_empty() > shoudl work right?
Yes. list_empty() is OK.
> > > spin_unlock_irq(&n->list_lock); > > goto out; > > } > > > > - page = list_entry(p, struct page, lru); > > + page = list_last_entry(&n->slabs_free, struct page, lru); > > last???
The original code delete the page from the tail of slabs_free list.
> > Would the the other new function that returns NULL on the empty list or > the pointer not be useful here too and save some code?
Sorry, I don't really understand what do you mean. Can you please specify it a little bit?
Thanks.
- Geliang
> > This patch seems to make it difficult to understand the code.
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