Messages in this thread | | | Date | Wed, 27 Feb 2008 10:05:04 +0200 | From | "Pekka Enberg" <> | Subject | Re: [PATCH 00/28] Swap over NFS -v16 |
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Hi Peter,
On Wed, Feb 27, 2008 at 9:58 AM, Peter Zijlstra <a.p.zijlstra@chello.nl> wrote: > > 1/ I note there is no way to tell if memory returned by kmalloc is > > from the emergency reserve - which contrasts with alloc_page > > which does make that information available through page->reserve. > > This seems a slightly unfortunate aspect of the interface. > > Yes, but alas there is no room to store such information in kmalloc(). > That is, in a sane way. I think it was Daniel Phillips who suggested > encoding it in the return pointer by flipping the low bit - but that is > just too ugly and breaks all current kmalloc sites to boot.
Why can't you add a kmem_is_emergency() to SLUB that looks up the cache/slab/page (whatever is the smallest unit of the emergency pool here) for the object and use that?
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