Juergen Gross
2018-Feb-27 07:44 UTC
[v2 1/1] xen, mm: Allow deferred page initialization for xen pv domains
On 26/02/18 17:01, Pavel Tatashin wrote:> Juergen Gross noticed that commit > f7f99100d8d ("mm: stop zeroing memory during allocation in vmemmap") > broke XEN PV domains when deferred struct page initialization is enabled. > > This is because the xen's PagePinned() flag is getting erased from struct > pages when they are initialized later in boot. > > Juergen fixed this problem by disabling deferred pages on xen pv domains. > It is desirable, however, to have this feature available as it reduces boot > time. This fix re-enables the feature for pv-dmains, and fixes the problem > the following way: > > The fix is to delay setting PagePinned flag until struct pages for all > allocated memory are initialized, i.e. until after free_all_bootmem(). > > A new x86_init.hyper op init_after_bootmem() is called to let xen know > that boot allocator is done, and hence struct pages for all the allocated > memory are now initialized. If deferred page initialization is enabled, the > rest of struct pages are going to be initialized later in boot once > page_alloc_init_late() is called. > > xen_after_bootmem() walks page table's pages and marks them pinned. > > Signed-off-by: Pavel Tatashin <pasha.tatashin at oracle.com>Verified to work on a system where the original issue caused a crash. Reviewed-by: Juergen Gross <jgross at suse.com> Tested-by: Juergen Gross <jgross at suse.com> Juergen