lkml.org 
[lkml]   [2020]   [Feb]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH RESEND v6 00/16] mm: Page fault enhancements
I tested the entire patchset because I'm very interested in fault
retries with userfaultfd and the series has been stable and worked
well on x86.

Tested-by: Brian Geffon <bgeffon@google.com>


On Thu, Feb 20, 2020 at 7:54 AM Peter Xu <peterx@redhat.com> wrote:
>
> [Resend v6]
>
> This is v6 of the series. It is majorly a rebase to 5.6-rc2, nothing
> else to be expected (plus some tests after the rebase). Instead of
> rewrite the cover letter I decided to use what we have for v5.
>
> Adding extra CCs for both Bobby Powers <bobbypowers@gmail.com> and
> Brian Geffon <bgeffon@google.com>.
>
> Online repo: https://github.com/xzpeter/linux/tree/mm-pf-signal-retry
>
> Any review comment is appreciated. Thanks,
>
> =============== v5 cover letter ==================
>
> This is v5 of the series. As Matthew suggested, I split the previous
> patch "mm: Return faster for non-fatal signals in user mode faults"
> into a few smaller ones:
>
> 1. One patch to introduce fatal_signal_pending(), and use it in
> archs that can directly apply
>
> 2. A few more patches to let the rest archs to use the new helper.
> With that we can have an unified entry for signal detection
>
> 3. One last patch to change fatal_signal_pending() to detect
> userspace non-fatal signal
>
> Nothing should have changed in the rest patches. Because the fault
> retry patches will depend on the previous ones, I decided to simply
> repost all the patches.
>
> Here's the new patchset layout:
>
> Patch 1-2: cleanup, and potential bugfix of hugetlbfs on fault retry
>
> Patch 3-9: let page fault to respond to non-fatal signals faster
>
> Patch 10: remove the userfaultfd NOPAGE emulation
>
> Patch 11-14: allow page fault to retry more than once
>
> Patch 15-16: let gup code to use FAULT_FLAG_KILLABLE too
>
> 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.
>
> Smoke tested on x86 only.
>
> Thanks,
>
> v5:
> - split "mm: Return faster for non-fatal signals in user mode faults"
> into a few more patches, let all archs to use an unified entry for
> fast signal handling (fatal_signal_pending)
>
> 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 (16):
> mm/gup: Rename "nonblocking" to "locked" where proper
> mm/gup: Fix __get_user_pages() on fault retry of hugetlb
> mm: Introduce fault_signal_pending()
> x86/mm: Use helper fault_signal_pending()
> arc/mm: Use helper fault_signal_pending()
> arm64/mm: Use helper fault_signal_pending()
> powerpc/mm: Use helper fault_signal_pending()
> sh/mm: Use helper fault_signal_pending()
> mm: Return faster for non-fatal signals in user mode faults
> userfaultfd: Don't retake mmap_sem to emulate NOPAGE
> mm: Introduce FAULT_FLAG_DEFAULT
> mm: Introduce FAULT_FLAG_INTERRUPTIBLE
> 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 | 6 +--
> arch/arc/mm/fault.c | 35 +++++--------
> arch/arm/mm/fault.c | 7 +--
> arch/arm64/mm/fault.c | 26 +++------
> arch/hexagon/mm/vm_fault.c | 5 +-
> arch/ia64/mm/fault.c | 5 +-
> arch/m68k/mm/fault.c | 7 +--
> arch/microblaze/mm/fault.c | 5 +-
> arch/mips/mm/fault.c | 5 +-
> arch/nds32/mm/fault.c | 5 +-
> arch/nios2/mm/fault.c | 7 +--
> arch/openrisc/mm/fault.c | 5 +-
> arch/parisc/mm/fault.c | 8 ++-
> arch/powerpc/mm/fault.c | 20 ++-----
> arch/riscv/mm/fault.c | 9 +---
> arch/s390/mm/fault.c | 10 ++--
> arch/sh/mm/fault.c | 13 +++--
> arch/sparc/mm/fault_32.c | 5 +-
> arch/sparc/mm/fault_64.c | 5 +-
> arch/um/kernel/trap.c | 3 +-
> arch/unicore32/mm/fault.c | 8 ++-
> arch/x86/mm/fault.c | 30 +++++------
> arch/xtensa/mm/fault.c | 5 +-
> drivers/gpu/drm/ttm/ttm_bo_vm.c | 12 +++--
> fs/userfaultfd.c | 62 ++++++++++------------
> include/linux/mm.h | 81 ++++++++++++++++++++++++----
> include/linux/sched/signal.h | 14 +++++
> mm/filemap.c | 2 +-
> mm/gup.c | 93 +++++++++++++++++++++------------
> mm/hugetlb.c | 17 +++---
> mm/internal.h | 6 +--
> 31 files changed, 281 insertions(+), 240 deletions(-)
>
> --
> 2.24.1
>

\
 
 \ /
  Last update: 2020-02-21 20:27    [W:0.117 / U:0.284 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site