On 30.01.2020 15:57, Paul Durrant wrote: > Currently it is unsafe to assign a domheap page allocated with > MEMF_no_refcount to a domain because the domain't 'tot_pages' will not > be incremented, but will be decrement when the page is freed (since > free_domheap_pages() has no way of telling that the increment was skipped). > > This patch allocates a new 'count_info' bit for a PGC_extra flag > which is then used to mark pages when alloc_domheap_pages() is called > with MEMF_no_refcount. assign_pages() because it still needs to call > domain_adjust_tot_pages() to make sure the domain is appropriately > referenced. Hence it is modified to do that for PGC_extra pages even if it > is passed MEMF_no_refount. > > The number of PGC_extra pages assigned to a domain is tracked in a new > 'extra_pages' counter, which is then subtracted from 'total_pages' in > the domain_tot_pages() helper. Thus 'normal' page assignments will still > be appropriately checked against 'max_pages'. > > Signed-off-by: Paul Durrant <pdurr...@amazon.com>
Reviewed-by: Jan Beulich <jbeul...@suse.com> _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
