A couple of comments on memcgroup patches in your
high-priority initial section (I've not studied further yet)
If those are to go in, then the sooner the better, yes.
But though I argued for cgroup_disable=memory (or some such),
I think myself that taking it even further now (requiring an
additional cgroup_enable=memory at boottime to get the memcg
stuff you chose with CGROUP_MEM_RES_CTLR=y at build time) is
confusing overkill, just messing around.
Others think differently. A compromise would be to improve the
helptext for CGROUP_MEM_RES_CTLR (some of it is presently nonsense,
isn't it? Certainly there's a significant overhead, but it's the
32-bit struct page not the 64-bit which then suffers from crossing
cacheline boundaries). Not much point in mentioning
cgroup_disable=memory if those patches go in, but needs to say
cgroup_enable=memory bootoption also needed.
No, it was a good find from Shi, but you were right to think the patch
fishy, and Kame put in lots of work (thank you!) to identify the actual
culprit: he and Mel are discussing what the actual fix should be; and
we might want to choose a different fix for stable than for 2.6.26.
I think you should drop that memmap_init_zone patch: the cgroup
pointer is not the only field we assume is zeroed, both flags and
mapping can cause trouble if they were not originally zeroed.
Re-zero the whole struct page? No, far better to fix the
root of the corruption, that Kame and Mel are working on.
Hugh
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