[RFC v5 08/11] mm: Provide speculative fault infrastructure

From: Peter Zijlstra Provide infrastructure to do a speculative fault (not holding mmap_sem). The not holding of mmap_sem means we can race against VMA change/removal and page-table destruction. We use the SRCU VMA freeing to keep the VMA around. We use the VMA seqcount to

[RFC v5 08/11] mm: Provide speculative fault infrastructure

From: Peter Zijlstra Provide infrastructure to do a speculative fault (not holding mmap_sem). The not holding of mmap_sem means we can race against VMA change/removal and page-table destruction. We use the SRCU VMA freeing to keep the VMA around. We use the VMA seqcount to detect change