Messages in this thread | | | Date | Fri, 28 Mar 2008 20:08:33 +0200 | From | "Pekka Enberg" <> | Subject | Re: 2.6.25-rc7-git2: Reported regressions from 2.6.24 |
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Hi Linus,
On Fri, 28 Mar 2008, Pekka Enberg wrote: > > We clear GFP_ZERO in new_slab() so the normal kmalloc()/kzalloc() path > > should be fine but don't do it for kmalloc_large() nor > > kmalloc_large_node(). Is that the bug here?
On Fri, Mar 28, 2008 at 7:27 PM, Linus Torvalds <torvalds@linux-foundation.org> wrote: > Dammit, NO. > > The bug was that the commit I made (which was correct and robust) was then > partially reverted by Christoph for no good reason. At that point, > kmalloc_large() didn't even exist, so at that point the change was > "technically correct" (since the only user of gfpflags really did end up > clearing it somewhere deep in its callchain).
I was not implying that we should clear GFP_ZERO in kmalloc_large() but that we can hit the page allocator with GFP_ZERO via kmalloc() and kzalloc() for size > PAGE_SIZE allocations. And asking Christoph if that's the bug we're seeing here.
On Fri, Mar 28, 2008 at 7:27 PM, Linus Torvalds <torvalds@linux-foundation.org> wrote: > So the *last* thing we want to do is to clear GFP_ZERO in multiple subtle > places based on new random code being added. We want to clear it at the > top level, so that no other code never ever even has to _think_ about it!
We are clearing it in one place, just before calling alloc_pages. [Yes, it's hard to spot, it's in new_slab() where we call allocate_slab().] I'm okay with moving it to top level but I don't see how that fixes any of the bugs mentioned here.
Pekka
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