Messages in this thread | | | Subject | Re: [PATCH 2/2] SLUB: Disable debugging if it increases the minimum page order | From | Pekka Enberg <> | Date | Thu, 11 Jun 2009 18:11:59 +0300 |
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Hi Christoph,
On Thu, 11 Jun 2009, Pekka Enberg wrote: > > On Thu, 2009-06-11 at 09:43 -0400, Christoph Lameter wrote: > > > We have had that with SLAB. NO! This leads to the situation that some > > > slabs have debug on and some have not. You just do not know which. > > > > I do see your point but surely we don't want to use order 1 allocations > > in the fall-back case for kmalloc-4096? Couldn't we just add a printk > > saying that debug was disabled for the cache? After all, my patch is > > much better than what SLAB does.
On Thu, 2009-06-11 at 10:24 -0400, Christoph Lameter wrote: > If we are enabling global debugging then we are looking for memory > corruption in *all* slab caches. Disabling debugging of some cache behind > the scenes is bad even if this leads to order 1 allocations. > > We could refine the way to specify groups of slab caches that should have > debugging on.
I think my patch is the simplest solution here: it turns off debugging for those caches where the metadata bumps up the minimum allocation order and I suspect that we disable cache only for 4096 in practice.
Also note that when we switch back to more aggressive page allocator pass-through, we lose SLUB debugging support.
Pekka
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