Re: [Xen-devel] tmem and construct_dom0 memory allocation race

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

On 19/06/2010 00:10, "Dulloor" <dulloor@xxxxxxxxx> wrote:

> Following is the sequence :
> - init_tmem allocates a set of pages and sets up dstmem and workmem to
> alloc pages in MP case (with cpu notifiers)
> - construct_dom0 estimates nr_pages by calling avail_domheap_pages
> - On other CPUs, tmem cpu_notifier gets called and allocates pages
> from domheap, making the construct_dom0's estimate stale.
> - construct_dom0 fails
> 
> tmem=off or dom0_mem=xxx both solve the problem for now.

Xen boot is pretty serialised. In particular SMP boot, and all cpu
notification calls, should be done before dom0 is constructed. So, have you
actually seen this race?

 -- Keir



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