* [GIT PULL] TIF_NOTIFY_SIGNAL for all archs
@ 2020-12-16 14:33 Jens Axboe
2020-12-16 21:17 ` pr-tracker-bot
0 siblings, 1 reply; 6+ messages in thread
From: Jens Axboe @ 2020-12-16 14:33 UTC (permalink / raw)
To: Linus Torvalds; +Cc: linux-kernel, Thomas Gleixner
Hi Linus,
This pull sits on top of of the core entry/exit and x86 entry branch
from the tip tree, which contains the generic and x86 parts of this
work. Here we convert the rest of the archs to support
TIF_NOTIFY_SIGNAL. With that done, we can get rid of JOBCTL_TASK_WORK
from task_work and signal.c, and also remove a deadlock work-around in
io_uring around knowing that signal based task_work waking is invoked
with the sighand wait queue head lock.
The motivation for this work is to decouple signal notify based
task_work, of which io_uring is a heavy user of, from sighand. The
sighand lock becomes a huge contention point, particularly for threaded
workloads where it's shared between threads. Even outside of threaded
applications it's slower than it needs to be.
Roman Gershman <romger@amazon.com> reported that his networked workload
dropped from 1.6M QPS at 80% CPU to 1.0M QPS at 100% CPU after io_uring
was changed to use TIF_NOTIFY_SIGNAL. The time was all spent hammering
on the sighand lock, showing 57% of the CPU time there [1].
There are further cleanups possible on top of this. One example is
TIF_PATCH_PENDING, where a patch already exists to use TIF_NOTIFY_SIGNAL
instead. Hopefully this will also lead to more consolidation, but the
work stands on its own as well.
This throws a trivial merge conflict with arm64 since you pulled that,
which is just a renumbering exercise and fiddling with _TIF_WORK_MASK in
that same file (arch/arm64/include/asm/thread_info.h).
[1] https://github.com/axboe/liburing/issues/215
Please pull!
The following changes since commit f8394f232b1eab649ce2df5c5f15b0e528c92091:
Linux 5.10-rc3 (2020-11-08 16:10:16 -0800)
are available in the Git repository at:
git://git.kernel.dk/linux-block.git tags/tif-task_work.arch-2020-12-14
for you to fetch changes up to 355fb9e2b78e78b38ec00f5cd9b05c6aceb98335:
io_uring: remove 'twa_signal_ok' deadlock work-around (2020-12-12 09:17:38 -0700)
----------------------------------------------------------------
tif-task_work.arch-2020-12-14
----------------------------------------------------------------
Jens Axboe (30):
Merge tag 'core-entry-notify-signal' of git://git.kernel.org/.../tip/tip into tif-task_work.arch
Merge branch 'x86/entry' of git://git.kernel.org/.../tip/tip into tif-task_work.arch
arc: add support for TIF_NOTIFY_SIGNAL
arm64: add support for TIF_NOTIFY_SIGNAL
m68k: add support for TIF_NOTIFY_SIGNAL
nios32: add support for TIF_NOTIFY_SIGNAL
parisc: add support for TIF_NOTIFY_SIGNAL
powerpc: add support for TIF_NOTIFY_SIGNAL
mips: add support for TIF_NOTIFY_SIGNAL
s390: add support for TIF_NOTIFY_SIGNAL
um: add support for TIF_NOTIFY_SIGNAL
sh: add support for TIF_NOTIFY_SIGNAL
openrisc: add support for TIF_NOTIFY_SIGNAL
csky: add support for TIF_NOTIFY_SIGNAL
hexagon: add support for TIF_NOTIFY_SIGNAL
microblaze: add support for TIF_NOTIFY_SIGNAL
arm: add support for TIF_NOTIFY_SIGNAL
xtensa: add support for TIF_NOTIFY_SIGNAL
alpha: add support for TIF_NOTIFY_SIGNAL
c6x: add support for TIF_NOTIFY_SIGNAL
h8300: add support for TIF_NOTIFY_SIGNAL
ia64: add support for TIF_NOTIFY_SIGNAL
nds32: add support for TIF_NOTIFY_SIGNAL
riscv: add support for TIF_NOTIFY_SIGNAL
sparc: add support for TIF_NOTIFY_SIGNAL
task_work: remove legacy TWA_SIGNAL path
io_uring: JOBCTL_TASK_WORK is no longer used by task_work
signal: kill JOBCTL_TASK_WORK
kernel: remove checking for TIF_NOTIFY_SIGNAL
io_uring: remove 'twa_signal_ok' deadlock work-around
arch/alpha/include/asm/thread_info.h | 2 ++
arch/alpha/kernel/entry.S | 2 +-
arch/alpha/kernel/signal.c | 2 +-
arch/arc/include/asm/thread_info.h | 4 ++-
arch/arc/kernel/entry.S | 3 ++-
arch/arc/kernel/signal.c | 2 +-
arch/arm/include/asm/thread_info.h | 7 +++++-
arch/arm/kernel/entry-common.S | 6 ++---
arch/arm/kernel/entry-v7m.S | 2 +-
arch/arm/kernel/signal.c | 2 +-
arch/arm64/include/asm/thread_info.h | 5 +++-
arch/arm64/kernel/signal.c | 2 +-
arch/c6x/include/asm/thread_info.h | 1 +
arch/c6x/kernel/asm-offsets.c | 1 +
arch/c6x/kernel/signal.c | 3 ++-
arch/csky/include/asm/thread_info.h | 5 +++-
arch/csky/kernel/signal.c | 2 +-
arch/h8300/include/asm/thread_info.h | 4 ++-
arch/h8300/kernel/signal.c | 2 +-
arch/hexagon/include/asm/thread_info.h | 2 ++
arch/hexagon/kernel/process.c | 2 +-
arch/ia64/include/asm/thread_info.h | 4 ++-
arch/ia64/kernel/process.c | 3 ++-
arch/m68k/include/asm/thread_info.h | 1 +
arch/m68k/kernel/signal.c | 3 ++-
arch/microblaze/include/asm/thread_info.h | 2 ++
arch/microblaze/kernel/signal.c | 3 ++-
arch/mips/include/asm/thread_info.h | 4 ++-
arch/mips/kernel/signal.c | 2 +-
arch/nds32/include/asm/thread_info.h | 2 ++
arch/nds32/kernel/ex-exit.S | 2 +-
arch/nds32/kernel/signal.c | 2 +-
arch/nios2/include/asm/thread_info.h | 2 ++
arch/nios2/kernel/signal.c | 3 ++-
arch/openrisc/include/asm/thread_info.h | 2 ++
arch/openrisc/kernel/signal.c | 2 +-
arch/parisc/include/asm/thread_info.h | 4 ++-
arch/parisc/kernel/signal.c | 3 ++-
arch/powerpc/include/asm/thread_info.h | 5 +++-
arch/powerpc/kernel/signal.c | 2 +-
arch/riscv/include/asm/thread_info.h | 5 +++-
arch/riscv/kernel/signal.c | 2 +-
arch/s390/include/asm/thread_info.h | 2 ++
arch/s390/kernel/entry.S | 11 +++++----
arch/s390/kernel/signal.c | 2 +-
arch/sh/include/asm/thread_info.h | 4 ++-
arch/sh/kernel/signal_32.c | 2 +-
arch/sparc/include/asm/thread_info_32.h | 4 ++-
arch/sparc/include/asm/thread_info_64.h | 6 +++--
arch/sparc/kernel/signal_32.c | 2 +-
arch/sparc/kernel/signal_64.c | 2 +-
arch/um/include/asm/thread_info.h | 2 ++
arch/um/kernel/process.c | 3 ++-
arch/xtensa/include/asm/thread_info.h | 5 +++-
arch/xtensa/kernel/entry.S | 4 +--
arch/xtensa/kernel/signal.c | 3 ++-
fs/io_uring.c | 30 ++++++-----------------
include/linux/entry-common.h | 4 ---
include/linux/sched/jobctl.h | 4 +--
include/linux/sched/signal.h | 2 --
include/linux/tracehook.h | 4 ---
kernel/signal.c | 22 -----------------
kernel/task_work.c | 30 +----------------------
63 files changed, 128 insertions(+), 139 deletions(-)
--
Jens Axboe
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [GIT PULL] TIF_NOTIFY_SIGNAL for all archs
2020-12-16 14:33 [GIT PULL] TIF_NOTIFY_SIGNAL for all archs Jens Axboe
@ 2020-12-16 21:17 ` pr-tracker-bot
2020-12-16 22:04 ` [PATCH] arm64: make _TIF_WORK_MASK bits contiguous (was: Re: [GIT PULL] TIF_NOTIFY_SIGNAL for all archs) Mark Rutland
0 siblings, 1 reply; 6+ messages in thread
From: pr-tracker-bot @ 2020-12-16 21:17 UTC (permalink / raw)
To: Jens Axboe; +Cc: Linus Torvalds, linux-kernel, Thomas Gleixner
The pull request you sent on Wed, 16 Dec 2020 07:33:42 -0700:
> git://git.kernel.dk/linux-block.git tags/tif-task_work.arch-2020-12-14
has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/005b2a9dc819a1265a8c765595f8f6d88d6173d9
Thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/prtracker.html
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH] arm64: make _TIF_WORK_MASK bits contiguous (was: Re: [GIT PULL] TIF_NOTIFY_SIGNAL for all archs)
2020-12-16 21:17 ` pr-tracker-bot
@ 2020-12-16 22:04 ` Mark Rutland
2020-12-16 22:06 ` Linus Torvalds
0 siblings, 1 reply; 6+ messages in thread
From: Mark Rutland @ 2020-12-16 22:04 UTC (permalink / raw)
To: Linus Torvalds
Cc: Jens Axboe, linux-kernel, Thomas Gleixner, pr-tracker-bot,
catalin.marinas, will
Hi Linus,
On Wed, Dec 16, 2020 at 09:17:39PM +0000, pr-tracker-bot@kernel.org wrote:
> > git://git.kernel.dk/linux-block.git tags/tif-task_work.arch-2020-12-14
>
> has been merged into torvalds/linux.git:
> https://git.kernel.org/torvalds/c/005b2a9dc819a1265a8c765595f8f6d88d6173d9
Unfortunately the merge resolution broke the build for arm64 -- could
you please apply the fixup below? IIUC that matches what we did in
linux-next, and builds fine locally.
Thanks,
Mark.
---->8----
From da1826cc5132bb9d46aebdb47fa033f94825a697 Mon Sep 17 00:00:00 2001
From: Mark Rutland <mark.rutland@arm.com>
Date: Wed, 16 Dec 2020 21:32:48 +0000
Subject: [PATCH] arm64: make _TIF_WORK_MASK bits contiguous
We need the bits of _TIF_WORK_MASK to be contiguous in order to to use
this as an immediate argument to an AND instruction in entry.S.
We happened to change these bits in commits:
b5a5a01d8e9a44ec ("arm64: uaccess: remove addr_limit_user_check()")
192caabd4dd92c98 ("arm64: add support for TIF_NOTIFY_SIGNAL")
... which each worked in isolation, but the merge resolution in commit:
005b2a9dc819a126 ("Merge tag 'tif-task_work.arch-2020-12-14' of git://git.kernel.dk/linux-block")
... happened to make the bits non-contiguous.
Fix this by moving TIF_NOTIFY_SIGNAL to be bit 6, which is contiguous
with the rest of _TIF_WORK_MASK.
Otherwise, we'll get a build-time failure as below:
| arch/arm64/kernel/entry.S: Assembler messages:
| arch/arm64/kernel/entry.S:733: Error: immediate out of range at operand 3 -- `and x2,x19,#((1<<1)|(1<<0)|(1<<2)|(1<<3)|(1<<4)|(1<<5)|(1<<7))'
| scripts/Makefile.build:360: recipe for target 'arch/arm64/kernel/entry.o' failed
| make[2]: *** [arch/arm64/kernel/entry.o] Error 1
| scripts/Makefile.build:496: recipe for target 'arch/arm64/kernel' failed
| make[1]: *** [arch/arm64/kernel] Error 2
| Makefile:1805: recipe for target 'arch/arm64' failed
| make: *** [arch/arm64] Error 2
Fixes: 005b2a9dc819a126 ("Merge tag 'tif-task_work.arch-2020-12-14' of git://git.kernel.dk/linux-block")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
---
arch/arm64/include/asm/thread_info.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index b24056a0b02b..9f4e3b266f21 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -64,7 +64,7 @@ void arch_release_task_struct(struct task_struct *tsk);
#define TIF_FOREIGN_FPSTATE 3 /* CPU's FP state is not current's */
#define TIF_UPROBE 4 /* uprobe breakpoint or singlestep */
#define TIF_MTE_ASYNC_FAULT 5 /* MTE Asynchronous Tag Check Fault */
-#define TIF_NOTIFY_SIGNAL 7 /* signal notifications exist */
+#define TIF_NOTIFY_SIGNAL 6 /* signal notifications exist */
#define TIF_SYSCALL_TRACE 8 /* syscall trace active */
#define TIF_SYSCALL_AUDIT 9 /* syscall auditing */
#define TIF_SYSCALL_TRACEPOINT 10 /* syscall tracepoint for ftrace */
--
2.11.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] arm64: make _TIF_WORK_MASK bits contiguous (was: Re: [GIT PULL] TIF_NOTIFY_SIGNAL for all archs)
2020-12-16 22:04 ` [PATCH] arm64: make _TIF_WORK_MASK bits contiguous (was: Re: [GIT PULL] TIF_NOTIFY_SIGNAL for all archs) Mark Rutland
@ 2020-12-16 22:06 ` Linus Torvalds
2020-12-16 22:11 ` [PATCH] arm64: make _TIF_WORK_MASK bits contiguous Jens Axboe
2020-12-16 22:14 ` [PATCH] arm64: make _TIF_WORK_MASK bits contiguous (was: Re: [GIT PULL] TIF_NOTIFY_SIGNAL for all archs) Catalin Marinas
0 siblings, 2 replies; 6+ messages in thread
From: Linus Torvalds @ 2020-12-16 22:06 UTC (permalink / raw)
To: Mark Rutland
Cc: Jens Axboe, linux-kernel, Thomas Gleixner, pr-tracker-bot,
Catalin Marinas, Will Deacon
On Wed, Dec 16, 2020 at 2:04 PM Mark Rutland <mark.rutland@arm.com> wrote:
>
> Unfortunately the merge resolution broke the build for arm64 -- could
> you please apply the fixup below? IIUC that matches what we did in
> linux-next, and builds fine locally.
Oops. That was a bit too subtle. I didn't realize that the bits really
wanted to be contiguous, and it wasn't obvious at the point of
conflict.
Will apply your fix asap.
Linus
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] arm64: make _TIF_WORK_MASK bits contiguous
2020-12-16 22:06 ` Linus Torvalds
@ 2020-12-16 22:11 ` Jens Axboe
2020-12-16 22:14 ` [PATCH] arm64: make _TIF_WORK_MASK bits contiguous (was: Re: [GIT PULL] TIF_NOTIFY_SIGNAL for all archs) Catalin Marinas
1 sibling, 0 replies; 6+ messages in thread
From: Jens Axboe @ 2020-12-16 22:11 UTC (permalink / raw)
To: Linus Torvalds, Mark Rutland
Cc: linux-kernel, Thomas Gleixner, pr-tracker-bot, Catalin Marinas,
Will Deacon
On 12/16/20 3:06 PM, Linus Torvalds wrote:
> On Wed, Dec 16, 2020 at 2:04 PM Mark Rutland <mark.rutland@arm.com> wrote:
>>
>> Unfortunately the merge resolution broke the build for arm64 -- could
>> you please apply the fixup below? IIUC that matches what we did in
>> linux-next, and builds fine locally.
>
> Oops. That was a bit too subtle. I didn't realize that the bits really
> wanted to be contiguous, and it wasn't obvious at the point of
> conflict.
>
> Will apply your fix asap.
Thanks (both Mark and Linus), I didn't know they had to be contiguous
either as an immediate value...
--
Jens Axboe
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] arm64: make _TIF_WORK_MASK bits contiguous (was: Re: [GIT PULL] TIF_NOTIFY_SIGNAL for all archs)
2020-12-16 22:06 ` Linus Torvalds
2020-12-16 22:11 ` [PATCH] arm64: make _TIF_WORK_MASK bits contiguous Jens Axboe
@ 2020-12-16 22:14 ` Catalin Marinas
1 sibling, 0 replies; 6+ messages in thread
From: Catalin Marinas @ 2020-12-16 22:14 UTC (permalink / raw)
To: Linus Torvalds
Cc: Mark Rutland, Jens Axboe, linux-kernel, Thomas Gleixner,
pr-tracker-bot, Will Deacon
On Wed, Dec 16, 2020 at 02:06:46PM -0800, Linus Torvalds wrote:
> On Wed, Dec 16, 2020 at 2:04 PM Mark Rutland <mark.rutland@arm.com> wrote:
> > Unfortunately the merge resolution broke the build for arm64 -- could
> > you please apply the fixup below? IIUC that matches what we did in
> > linux-next, and builds fine locally.
>
> Oops. That was a bit too subtle. I didn't realize that the bits really
> wanted to be contiguous, and it wasn't obvious at the point of
> conflict.
>
> Will apply your fix asap.
Thanks Linus for applying it and thanks Mark for the quick fix. I
noticed it in -next before and gave Stephen my conflict resolution.
--
Catalin
^ permalink raw reply [flat|nested] 6+ messages in thread
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2020-12-16 14:33 [GIT PULL] TIF_NOTIFY_SIGNAL for all archs Jens Axboe
2020-12-16 21:17 ` pr-tracker-bot
2020-12-16 22:04 ` [PATCH] arm64: make _TIF_WORK_MASK bits contiguous (was: Re: [GIT PULL] TIF_NOTIFY_SIGNAL for all archs) Mark Rutland
2020-12-16 22:06 ` Linus Torvalds
2020-12-16 22:11 ` [PATCH] arm64: make _TIF_WORK_MASK bits contiguous Jens Axboe
2020-12-16 22:14 ` [PATCH] arm64: make _TIF_WORK_MASK bits contiguous (was: Re: [GIT PULL] TIF_NOTIFY_SIGNAL for all archs) Catalin Marinas
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