From: Thomas Gleixner <tglx@linutronix.de>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
LKML <linux-kernel@vger.kernel.org>
Cc: Michael Jeanson <mjeanson@efficios.com>,
Jens Axboe <axboe@kernel.dk>,
Peter Zijlstra <peterz@infradead.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
Boqun Feng <boqun.feng@gmail.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
x86@kernel.org, Arnd Bergmann <arnd@arndb.de>,
Heiko Carstens <hca@linux.ibm.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Sven Schnelle <svens@linux.ibm.com>,
Huacai Chen <chenhuacai@kernel.org>,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>
Subject: Re: [patch V4 27/36] rseq: Implement fast path for exit to user
Date: Thu, 11 Sep 2025 18:08:28 +0200 [thread overview]
Message-ID: <87y0qlq8eb.ffs@tglx> (raw)
In-Reply-To: <ad0e0d2c-75e0-42c2-85d4-5232a5fb8af9@efficios.com>
On Thu, Sep 11 2025 at 10:27, Mathieu Desnoyers wrote:
> On 2025-09-08 17:32, Thomas Gleixner wrote:
>> The initial decision to invoke any of this is based on two flags in the
>> event struct: @has_rseq and @sched_switch. The decision is in pseudo ASM:
>>
>> load tsk::event::has_rseq
>> and tsk::event::sched_switch
>
> I suspect that my earlier comment about has_rseq and AND applies here
> as well. We could probably remove the has_rseq load and the AND
> altogether and just load sched_switch for the conditional branch ?
Same comment as before.
next prev parent reply other threads:[~2025-09-11 16:08 UTC|newest]
Thread overview: 83+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-08 21:31 [patch V4 00/36] rseq: Optimize exit to user space Thomas Gleixner
2025-09-08 21:31 ` [patch V4 01/36] rseq: Avoid pointless evaluation in __rseq_notify_resume() Thomas Gleixner
2025-09-08 21:31 ` [patch V4 02/36] rseq: Condense the inline stubs Thomas Gleixner
2025-09-08 21:31 ` [patch V4 03/36] rseq: Move algorithm comment to top Thomas Gleixner
2025-09-08 21:31 ` [patch V4 04/36] rseq: Remove the ksig argument from rseq_handle_notify_resume() Thomas Gleixner
2025-09-08 21:31 ` [patch V4 05/36] rseq: Simplify registration Thomas Gleixner
2025-09-08 21:31 ` [patch V4 06/36] rseq: Simplify the event notification Thomas Gleixner
2025-09-09 13:18 ` Mathieu Desnoyers
2025-09-08 21:31 ` [patch V4 07/36] rseq, virt: Retrigger RSEQ after vcpu_run() Thomas Gleixner
2025-09-09 0:00 ` Sean Christopherson
2025-09-09 12:10 ` Thomas Gleixner
2025-09-09 13:21 ` Mathieu Desnoyers
2025-09-08 21:31 ` [patch V4 08/36] rseq: Avoid CPU/MM CID updates when no event pending Thomas Gleixner
2025-09-09 13:25 ` Mathieu Desnoyers
2025-09-08 21:31 ` [patch V4 09/36] rseq: Introduce struct rseq_data Thomas Gleixner
2025-09-09 13:30 ` Mathieu Desnoyers
2025-09-12 20:44 ` Thomas Gleixner
2025-09-12 21:33 ` Mathieu Desnoyers
2025-09-08 21:31 ` [patch V4 10/36] entry: Cleanup header Thomas Gleixner
2025-09-08 21:31 ` [patch V4 11/36] entry: Remove syscall_enter_from_user_mode_prepare() Thomas Gleixner
2025-09-09 13:33 ` Mathieu Desnoyers
2025-09-08 21:31 ` [patch V4 12/36] entry: Inline irqentry_enter/exit_from/to_user_mode() Thomas Gleixner
2025-09-09 13:38 ` Mathieu Desnoyers
2025-09-09 14:10 ` Thomas Gleixner
2025-09-09 14:59 ` Mathieu Desnoyers
2025-09-08 21:31 ` [patch V4 13/36] sched: Move MM CID related functions to sched.h Thomas Gleixner
2025-09-08 21:31 ` [patch V4 14/36] rseq: Cache CPU ID and MM CID values Thomas Gleixner
2025-09-09 13:43 ` Mathieu Desnoyers
2025-09-09 14:13 ` Thomas Gleixner
2025-09-09 15:01 ` Mathieu Desnoyers
2025-09-08 21:31 ` [patch V4 15/36] rseq: Record interrupt from user space Thomas Gleixner
2025-09-09 13:53 ` Mathieu Desnoyers
2025-09-09 14:17 ` Thomas Gleixner
2025-09-09 15:05 ` Mathieu Desnoyers
2025-09-08 21:31 ` [patch V4 16/36] rseq: Provide tracepoint wrappers for inline code Thomas Gleixner
2025-09-08 21:31 ` [patch V4 17/36] rseq: Expose lightweight statistics in debugfs Thomas Gleixner
2025-09-08 21:32 ` [patch V4 18/36] rseq: Provide static branch for runtime debugging Thomas Gleixner
2025-09-08 21:32 ` [patch V4 19/36] rseq: Provide and use rseq_update_user_cs() Thomas Gleixner
2025-09-09 15:11 ` Mathieu Desnoyers
2025-09-08 21:32 ` [patch V4 20/36] rseq: Replace the original debug implementation Thomas Gleixner
2025-09-08 21:32 ` [patch V4 21/36] rseq: Make exit debugging static branch based Thomas Gleixner
2025-09-08 21:32 ` [patch V4 22/36] rseq: Use static branch for syscall exit debug when GENERIC_IRQ_ENTRY=y Thomas Gleixner
2025-09-08 21:32 ` [patch V4 23/36] rseq: Provide and use rseq_set_ids() Thomas Gleixner
2025-09-11 13:40 ` Mathieu Desnoyers
2025-09-11 16:02 ` Thomas Gleixner
2025-09-11 17:13 ` Mathieu Desnoyers
2025-09-08 21:32 ` [patch V4 24/36] rseq: Separate the signal delivery path Thomas Gleixner
2025-09-08 21:32 ` [patch V4 25/36] rseq: Rework the TIF_NOTIFY handler Thomas Gleixner
2025-09-08 21:32 ` [patch V4 26/36] rseq: Optimize event setting Thomas Gleixner
2025-09-11 14:03 ` Mathieu Desnoyers
2025-09-11 16:06 ` Thomas Gleixner
2025-09-11 17:15 ` Mathieu Desnoyers
2025-09-12 6:58 ` Thomas Gleixner
2025-09-08 21:32 ` [patch V4 27/36] rseq: Implement fast path for exit to user Thomas Gleixner
2025-09-11 14:27 ` Mathieu Desnoyers
2025-09-11 16:08 ` Thomas Gleixner [this message]
2025-09-08 21:32 ` [patch V4 28/36] rseq: Switch to fast path processing on " Thomas Gleixner
2025-09-11 14:44 ` Mathieu Desnoyers
2025-09-11 14:45 ` Mathieu Desnoyers
2025-09-11 16:50 ` Thomas Gleixner
2025-09-11 16:47 ` Thomas Gleixner
2025-09-11 20:00 ` Mathieu Desnoyers
2025-09-12 14:22 ` Thomas Gleixner
2025-09-12 15:44 ` Mathieu Desnoyers
2025-09-08 21:32 ` [patch V4 29/36] entry: Split up exit_to_user_mode_prepare() Thomas Gleixner
2025-09-08 21:32 ` [patch V4 30/36] rseq: Split up rseq_exit_to_user_mode() Thomas Gleixner
2025-09-08 21:32 ` [patch V4 31/36] asm-generic: Provide generic TIF infrastructure Thomas Gleixner
2025-09-17 6:16 ` [tip: core/core] " tip-bot2 for Thomas Gleixner
2025-09-08 21:32 ` [patch V4 32/36] x86: Use generic TIF bits Thomas Gleixner
2025-09-17 6:16 ` [tip: core/core] " tip-bot2 for Thomas Gleixner
2025-09-08 21:32 ` [patch V4 33/36] s390: " Thomas Gleixner
2025-09-11 9:11 ` Sven Schnelle
2025-09-11 11:03 ` Heiko Carstens
2025-09-17 6:16 ` [tip: core/core] " tip-bot2 for Thomas Gleixner
2025-09-08 21:32 ` [patch V4 34/36] loongarch: " Thomas Gleixner
2025-09-17 6:16 ` [tip: core/core] " tip-bot2 for Thomas Gleixner
2025-09-08 21:32 ` [patch V4 35/36] riscv: " Thomas Gleixner
2025-09-17 6:16 ` [tip: core/core] " tip-bot2 for Thomas Gleixner
2025-09-08 21:32 ` [patch V4 36/36] rseq: Switch to TIF_RSEQ if supported Thomas Gleixner
2025-09-10 13:55 ` [patch V4 00/36] rseq: Optimize exit to user space Jens Axboe
2025-09-10 14:45 ` Michael Jeanson
2025-09-10 15:34 ` Jens Axboe
2025-09-10 14:54 ` Thomas Gleixner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87y0qlq8eb.ffs@tglx \
--to=tglx@linutronix.de \
--cc=arnd@arndb.de \
--cc=axboe@kernel.dk \
--cc=boqun.feng@gmail.com \
--cc=borntraeger@linux.ibm.com \
--cc=chenhuacai@kernel.org \
--cc=decui@microsoft.com \
--cc=hca@linux.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mathieu.desnoyers@efficios.com \
--cc=mjeanson@efficios.com \
--cc=palmer@dabbelt.com \
--cc=paul.walmsley@sifive.com \
--cc=paulmck@kernel.org \
--cc=pbonzini@redhat.com \
--cc=peterz@infradead.org \
--cc=seanjc@google.com \
--cc=svens@linux.ibm.com \
--cc=wei.liu@kernel.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.