search for: p2m_mem_paging_prep

ging_prep ensures that an mfn is backing the paged-out gfn, and transitions to the next state in the paging state machine for this page. Foreign mappings of the gfn will now succeed. This is the key idea, as it allows the pager to now map the gfn and fill in its contents. Unfortunately, it also allows any other foreign mapper to map the gfn and read its contents. This is particularly dangerous

The following two patches are about how to speed up in xenpaging when page in pages. On suse11-64 with 4G memory,if we page out 2G pages,it will cost about 15.5 seconds, but take 2088 seconds to finish paging in.If page-in costs too much time,it will cause unmesurable problems when vm or dom0 access the paged_out page,such as BSOD,crash. What鈥檚 more,the dom0 is always in high I/O pressure.

The following two patches allow the parallel use of memsharing, xenpaging and xen-access by using an independent ring buffer for each feature. Please review. v2: - update mem_event_check_ring arguments, check domain rather than domain_id - check ring_full first because its value was just evaluated - check if ring buffer is initialized before calling mem_access_domctl/mem_paging_domctl