[RFC v3 00/17] Speculative page faults

From: Laurent Dufour
Date: Thu Apr 27 2017 - 11:53:41 EST


This is a port on kernel 4.10 of the work done by Peter Zijlstra to
handle page fault without holding the mm semaphore.

http://linux-kernel.2935.n7.nabble.com/RFC-PATCH-0-6-Another-go-at-speculative-page-faults-tt965642.html#none

This series is functional on x86, but there may be some pending
issues. It's building on top of v4.10.

Compared to the Peter initial work, this series introduces a try spin
lock when dealing with speculative page fault. This is required to
avoid dead lock when handling a page fault while a TLB invalidate is
requested by an other CPU holding the PTE. Another change due to a
lock dependency issue with mapping->i_mmap_rwsem.

This series also protect changes to VMA's data which are read or
change by the page fault handler. The protections is done through the
VMA's sequence number.

Laurent Dufour (11):
mm: Introduce pte_spinlock
mm/spf: Try spin lock in speculative path
mm/spf: Fix fe.sequence init in __handle_mm_fault()
mm/spf: don't set fault entry's fields if locking failed
mm/spf; fix lock dependency against mapping->i_mmap_rwsem
mm/spf: Protect changes to vm_flags
mm/spf Protect vm_policy's changes against speculative pf
x86/mm: Update the handle_speculative_fault's path
mm/spf: Add check on the VMA's flags
mm: protect madvise vs speculative pf
mm/spf: protect mremap() against speculative pf

Peter Zijlstra (6):
mm: Dont assume page-table invariance during faults
mm: Prepare for FAULT_FLAG_SPECULATIVE
mm: VMA sequence count
RCU free VMAs
mm: Provide speculative fault infrastructure
mm,x86: Add speculative pagefault handling

arch/x86/mm/fault.c | 15 +++
fs/proc/task_mmu.c | 2 +
include/linux/mm.h | 4 +
include/linux/mm_types.h | 3 +
kernel/fork.c | 1 +
mm/init-mm.c | 1 +
mm/internal.h | 18 +++
mm/madvise.c | 5 +-
mm/memory.c | 284 +++++++++++++++++++++++++++++++++++++++--------
mm/mempolicy.c | 10 +-
mm/mlock.c | 9 +-
mm/mmap.c | 121 +++++++++++++++-----
mm/mprotect.c | 2 +
mm/mremap.c | 7 ++
14 files changed, 402 insertions(+), 80 deletions(-)

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2.7.4