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Shutemov" , "Dr . David Alan Gilbert" Subject: [PATCH v4 00/10] mm: Page fault enhancements Date: Mon, 23 Sep 2019 12:25:13 +0800 Message-Id: <20190923042523.10027-1-peterx@redhat.com> X-Mailer: git-send-email 2.21.0 MIME-Version: 1.0 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: This is the 4th version of the PF enhancement series on signal handlings and fault retries. This new version does not change existing patches in v3 but added two more patches to address the current gup issue on not responding to SIGKILL. A 3rd new patch is also added to allow handle_userfaultfd to respect FAULT_FLAG_KILLABLE though should have no functional change when with the two new patches above. I would really appreciate any review comments for the series, especially for the first two patches which IMHO are even not related to this patchset and they should either cleanup or fix things. v4: - use lore.kernel.org for all the links in commit messages [Kirill] - one more patch ("mm/gup: Fix __get_user_pages() on fault retry of hugetlb") to fix hugetlb path on fault retry - one more patch ("mm/gup: Allow to react to fatal signals") to: - use down_read_killable() properly [Linus] - pass in FAULT_FLAG_KILLABLE for all GUP [Linus] - one more patch ("mm/userfaultfd: Honor FAULT_FLAG_KILLABLE in fault path") to let handle_userfaultfd() respect FAULT_FLAG_KILLABLE. Should have no functional change after previous two new patches. v3: - check fatal signals in __get_user_page_locked() [Linus] - add r-bs v2: - resent previous version, rebase only =============== v1 cover letter ================== This series is split out of userfaultfd-wp series to only cover the general page fault changes, since it seems to make sense itself. Basically it does two things: (a) Allows the page fault handlers to be more interactive on not only SIGKILL, but also the rest of userspace signals (especially for user-mode faults), and, (b) Allows the page fault retry (VM_FAULT_RETRY) to happen for more than once. I'm keeping the CC list as in uffd-wp v5, hopefully I'm not sending too much spams... And, instead of writting again the cover letter, I'm just copy-pasting my previous link here which has more details on why we do this: https://patchwork.kernel.org/cover/10691991/ The major change from that latest version should be that we introduced a new page fault flag FAULT_FLAG_INTERRUPTIBLE as suggested by Linus [1] to represents that we would like the fault handler to respond to non-fatal signals. Also, we're more careful now on when to do the immediate return of the page fault for such signals. For example, now we'll only check against signal_pending() for user-mode page faults and we keep the kernel-mode page fault patch untouched for it. More information can be found in separate patches. The patchset is only lightly tested on x86. All comments are greatly welcomed. Thanks, [1] https://lkml.org/lkml/2019/6/25/1382 Peter Xu (10): mm/gup: Rename "nonblocking" to "locked" where proper mm/gup: Fix __get_user_pages() on fault retry of hugetlb mm: Introduce FAULT_FLAG_DEFAULT mm: Introduce FAULT_FLAG_INTERRUPTIBLE mm: Return faster for non-fatal signals in user mode faults userfaultfd: Don't retake mmap_sem to emulate NOPAGE mm: Allow VM_FAULT_RETRY for multiple times mm/gup: Allow VM_FAULT_RETRY for multiple times mm/gup: Allow to react to fatal signals mm/userfaultfd: Honor FAULT_FLAG_KILLABLE in fault path arch/alpha/mm/fault.c | 7 +-- arch/arc/mm/fault.c | 8 ++- arch/arm/mm/fault.c | 14 +++-- arch/arm64/mm/fault.c | 16 +++--- arch/hexagon/mm/vm_fault.c | 6 +-- arch/ia64/mm/fault.c | 6 +-- arch/m68k/mm/fault.c | 10 ++-- arch/microblaze/mm/fault.c | 6 +-- arch/mips/mm/fault.c | 6 +-- arch/nds32/mm/fault.c | 12 ++--- arch/nios2/mm/fault.c | 8 ++- arch/openrisc/mm/fault.c | 6 +-- arch/parisc/mm/fault.c | 9 ++-- arch/powerpc/mm/fault.c | 10 ++-- arch/riscv/mm/fault.c | 12 ++--- arch/s390/mm/fault.c | 11 ++-- arch/sh/mm/fault.c | 7 ++- arch/sparc/mm/fault_32.c | 5 +- arch/sparc/mm/fault_64.c | 6 +-- arch/um/kernel/trap.c | 7 +-- arch/unicore32/mm/fault.c | 11 ++-- arch/x86/mm/fault.c | 6 +-- arch/xtensa/mm/fault.c | 6 +-- drivers/gpu/drm/ttm/ttm_bo_vm.c | 12 +++-- fs/userfaultfd.c | 62 ++++++++++------------ include/linux/mm.h | 81 ++++++++++++++++++++++++---- include/linux/sched/signal.h | 12 +++++ mm/filemap.c | 2 +- mm/gup.c | 93 +++++++++++++++++++++------------ mm/hugetlb.c | 17 +++--- mm/shmem.c | 2 +- 31 files changed, 283 insertions(+), 193 deletions(-)