Messages in this thread | | | Date | Sun, 11 Feb 2024 20:54:29 -0600 | Subject | Re: [PATCH 2/2] x86/MCE: Add command line option to extend MCE Records pool | From | "Naik, Avadhut" <> |
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Hi,
On 2/11/2024 05:14, Borislav Petkov wrote: > On Sat, Feb 10, 2024 at 03:15:26PM -0600, Naik, Avadhut wrote: >> IIUC, you wouldn't want to extend the pool through late_initcall(). >> Instead, you would want for memory to be allocated (on the heap) and >> size of the pool to be set at the very beginning i.e. when the pool >> is created (~2 seconds, according to dmesg timestamps). >> >> Please correct me if I have understood wrong. > > Nah, you got it right. I went, looked and realized that we have to do > this early dance because we have no allocator yet. And we can't move > this gen_pool allocation to later, when we *do* have an allocator > because MCA is up and logging already. > Okay. Will make changes to allocate memory and set size of the pool when it is created. Also, will remove the command line parameter and resubmit.
> But your extending approach doesn't fly in all cases either: > > gen_pool_add->gen_pool_add_virt->gen_pool_add_owner > > it grabs the pool->lock spinlock and adds to &pool->chunks while, at the > exact same time, gen_pool_alloc(), in *NMI* context iterates over that > same &pool->chunks in the case we're logging an MCE at exact that same > time when you're extending the buffer. > > And Tony already said that in the thread you're quoting: > > https://lore.kernel.org/linux-edac/SJ1PR11MB60832922E4D036138FF390FAFCD7A@SJ1PR11MB6083.namprd11.prod.outlook.com/ > > So no, that doesn't work either. > > Thx.
Thanks for this explanation! >
-- Thanks, Avadhut Naik
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