All of lore.kernel.org
 help / color / mirror / Atom feed
From: Arnd Bergmann <arnd@arndb.de>
To: "André Almeida" <andrealmeid@collabora.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
	Alistair Francis <alistair.francis@opensource.wdc.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Alistair Francis <alistair23@gmail.com>,
	linux-riscv <linux-riscv@lists.infradead.org>,
	Namhyung Kim <namhyung@kernel.org>, Jiri Olsa <jolsa@redhat.com>,
	linux-perf-users@vger.kernel.org,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Davidlohr Bueso <dave@stgolabs.net>,
	Darren Hart <dvhart@infradead.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Atish Patra <atish.patra@wdc.com>,
	Alistair Francis <alistair.francis@wdc.com>
Subject: Re: [PATCH v3 2/2] perf bench: Add support for 32-bit systems with 64-bit time_t
Date: Wed, 22 Sep 2021 13:26:16 +0200	[thread overview]
Message-ID: <CAK8P3a0LsxOTYeM-o=Ee=XFD6zN7ESV_dhGmAOFSj_zJ8pBDgA@mail.gmail.com> (raw)
In-Reply-To: <9db8c79a-f704-84ce-360b-84335f926a48@collabora.com>

On Wed, Sep 22, 2021 at 1:06 AM André Almeida <andrealmeid@collabora.com> wrote:
> Às 05:08 de 21/09/21, Arnd Bergmann escreveu:
> > I would love to see the wrapper that Alistair wrote as part of some kernel
> > uapi header provided to user space. futex is used by tons of applications,
> > and we never had a library abstraction for it, so everyone has to do these
> > by hand, and they all get them slightly wrong in different ways.
>
> Why we don't have a futex() wrapper at glibc as we do have for others
> syscalls?

I think mainly because there was no agreement on what the calling
conventions should be:

The raw syscall is awkward because of the argument overloading that cannot
easily be expressed in standard C in a typesafe way. Having a per-operation
interface would avoid that problem but requires specifying what that
particular interface has to be, and there is no standard to fall back on for
this syscall.

       Arnd

WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de>
To: "André Almeida" <andrealmeid@collabora.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
	Alistair Francis <alistair.francis@opensource.wdc.com>,
	 Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Alistair Francis <alistair23@gmail.com>,
	 linux-riscv <linux-riscv@lists.infradead.org>,
	Namhyung Kim <namhyung@kernel.org>,  Jiri Olsa <jolsa@redhat.com>,
	linux-perf-users@vger.kernel.org,
	 Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Mark Rutland <mark.rutland@arm.com>,
	 Arnaldo Carvalho de Melo <acme@kernel.org>,
	Davidlohr Bueso <dave@stgolabs.net>,
	Darren Hart <dvhart@infradead.org>,
	 Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	 Thomas Gleixner <tglx@linutronix.de>,
	Atish Patra <atish.patra@wdc.com>,
	 Alistair Francis <alistair.francis@wdc.com>
Subject: Re: [PATCH v3 2/2] perf bench: Add support for 32-bit systems with 64-bit time_t
Date: Wed, 22 Sep 2021 13:26:16 +0200	[thread overview]
Message-ID: <CAK8P3a0LsxOTYeM-o=Ee=XFD6zN7ESV_dhGmAOFSj_zJ8pBDgA@mail.gmail.com> (raw)
In-Reply-To: <9db8c79a-f704-84ce-360b-84335f926a48@collabora.com>

On Wed, Sep 22, 2021 at 1:06 AM André Almeida <andrealmeid@collabora.com> wrote:
> Às 05:08 de 21/09/21, Arnd Bergmann escreveu:
> > I would love to see the wrapper that Alistair wrote as part of some kernel
> > uapi header provided to user space. futex is used by tons of applications,
> > and we never had a library abstraction for it, so everyone has to do these
> > by hand, and they all get them slightly wrong in different ways.
>
> Why we don't have a futex() wrapper at glibc as we do have for others
> syscalls?

I think mainly because there was no agreement on what the calling
conventions should be:

The raw syscall is awkward because of the argument overloading that cannot
easily be expressed in standard C in a typesafe way. Having a per-operation
interface would avoid that problem but requires specifying what that
particular interface has to be, and there is no standard to fall back on for
this syscall.

       Arnd

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

  reply	other threads:[~2021-09-22 11:26 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-17  6:10 [PATCH v3 1/2] perf benchmark: Call the futex syscall from a function Alistair Francis
2021-09-17  6:10 ` Alistair Francis
2021-09-17  6:10 ` [PATCH v3 2/2] perf bench: Add support for 32-bit systems with 64-bit time_t Alistair Francis
2021-09-17  6:10   ` Alistair Francis
2021-09-17  7:33   ` Arnd Bergmann
2021-09-17  7:33     ` Arnd Bergmann
2021-09-17 18:33   ` Davidlohr Bueso
2021-09-17 18:33     ` Davidlohr Bueso
2021-09-20 22:47   ` André Almeida
2021-09-20 22:47     ` André Almeida
2021-09-21  8:08     ` Arnd Bergmann
2021-09-21  8:08       ` Arnd Bergmann
2021-09-21 23:06       ` André Almeida
2021-09-21 23:06         ` André Almeida
2021-09-22 11:26         ` Arnd Bergmann [this message]
2021-09-22 11:26           ` Arnd Bergmann
2021-09-22 11:27         ` Arnd Bergmann
2021-09-22 11:27           ` Arnd Bergmann
2021-09-24  4:34       ` Alistair Francis
2021-09-24  4:34         ` Alistair Francis
2021-09-24  4:34     ` Alistair Francis
2021-09-24  4:34       ` Alistair Francis
2021-09-26 21:32       ` André Almeida
2021-09-26 21:32         ` André Almeida
2021-09-17 18:21 ` [PATCH v3 1/2] perf benchmark: Call the futex syscall from a function Davidlohr Bueso
2021-09-17 18:21   ` Davidlohr Bueso

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='CAK8P3a0LsxOTYeM-o=Ee=XFD6zN7ESV_dhGmAOFSj_zJ8pBDgA@mail.gmail.com' \
    --to=arnd@arndb.de \
    --cc=acme@kernel.org \
    --cc=alexander.shishkin@linux.intel.com \
    --cc=alistair.francis@opensource.wdc.com \
    --cc=alistair.francis@wdc.com \
    --cc=alistair23@gmail.com \
    --cc=andrealmeid@collabora.com \
    --cc=atish.patra@wdc.com \
    --cc=dave@stgolabs.net \
    --cc=dvhart@infradead.org \
    --cc=jolsa@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-perf-users@vger.kernel.org \
    --cc=linux-riscv@lists.infradead.org \
    --cc=mark.rutland@arm.com \
    --cc=mingo@redhat.com \
    --cc=namhyung@kernel.org \
    --cc=peterz@infradead.org \
    --cc=tglx@linutronix.de \
    /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.