Messages in this thread | | | Date | Fri, 4 Dec 2015 10:16:38 -0600 (CST) | From | Christoph Lameter <> | Subject | Re: [PATCH v2] mm/slab.c: use list_{empty_careful,last_entry} in drain_freelist |
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On Fri, 4 Dec 2015, Geliang Tang wrote:
> 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.
Maybe make the code clearer by using another method to get the page pointer?
> > > > 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?
I take that back. list_empty is the best choice here.
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