All of lore.kernel.org
 help / color / mirror / Atom feed
From: "Andy Lutomirski" <luto@kernel.org>
To: "Sohil Mehta" <sohil.mehta@intel.com>,
	"the arch/x86 maintainers" <x86@kernel.org>
Cc: "Tony Luck" <tony.luck@intel.com>,
	"Dave Hansen" <dave.hansen@intel.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Borislav Petkov" <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>, "Jens Axboe" <axboe@kernel.dk>,
	"Christian Brauner" <christian@brauner.io>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	"Shuah Khan" <shuah@kernel.org>, "Arnd Bergmann" <arnd@arndb.de>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"Raj Ashok" <ashok.raj@intel.com>,
	"Jacob Pan" <jacob.jun.pan@linux.intel.com>,
	"Gayatri Kammela" <gayatri.kammela@intel.com>,
	"Zeng Guang" <guang.zeng@intel.com>,
	"Williams, Dan J" <dan.j.williams@intel.com>,
	"Randy E Witt" <randy.e.witt@intel.com>,
	"Shankar, Ravi V" <ravi.v.shankar@intel.com>,
	"Ramesh Thomas" <ramesh.thomas@intel.com>,
	"Linux API" <linux-api@vger.kernel.org>,
	linux-arch@vger.kernel.org,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
	linux-kselftest@vger.kernel.org
Subject: Re: [RFC PATCH 11/13] x86/uintr: Introduce uintr_wait() syscall
Date: Tue, 28 Sep 2021 20:30:27 -0700	[thread overview]
Message-ID: <f5a971e4-6b0d-477f-992c-89110a2ceb03@www.fastmail.com> (raw)
In-Reply-To: <20210913200132.3396598-12-sohil.mehta@intel.com>

On Mon, Sep 13, 2021, at 1:01 PM, Sohil Mehta wrote:
> Add a new system call to allow applications to block in the kernel and
> wait for user interrupts.
>

...

>
> When the application makes this syscall the notification vector is
> switched to a new kernel vector. Any new SENDUIPI will invoke the kernel
> interrupt which is then used to wake up the process.

Any new SENDUIPI that happens to hit the target CPU's ucode at a time when the kernel vector is enabled will deliver the interrupt.  Any new SENDUIPI that happens to hit the target CPU's ucode at a time when a different UIPI-using task is running will *not* deliver the interrupt, unless I'm missing some magic.  Which means that wakeups will be missed, which I think makes this whole idea a nonstarter.

Am I missing something?

  parent reply	other threads:[~2021-09-29  3:30 UTC|newest]

Thread overview: 89+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-13 20:01 [RFC PATCH 00/13] x86 User Interrupts support Sohil Mehta
2021-09-13 20:01 ` [RFC PATCH 01/13] x86/uintr/man-page: Include man pages draft for reference Sohil Mehta
2021-09-13 20:01 ` [RFC PATCH 02/13] Documentation/x86: Add documentation for User Interrupts Sohil Mehta
2021-09-13 20:01 ` [RFC PATCH 03/13] x86/cpu: Enumerate User Interrupts support Sohil Mehta
2021-09-23 22:24   ` Thomas Gleixner
2021-09-24 19:59     ` Sohil Mehta
2021-09-27 20:42     ` Sohil Mehta
2021-09-13 20:01 ` [RFC PATCH 04/13] x86/fpu/xstate: Enumerate User Interrupts supervisor state Sohil Mehta
2021-09-23 22:34   ` Thomas Gleixner
2021-09-27 22:25     ` Sohil Mehta
2021-09-13 20:01 ` [RFC PATCH 05/13] x86/irq: Reserve a user IPI notification vector Sohil Mehta
2021-09-23 23:07   ` Thomas Gleixner
2021-09-25 13:30     ` Thomas Gleixner
2021-09-26 12:39       ` Thomas Gleixner
2021-09-27 19:07         ` Sohil Mehta
2021-09-28  8:11           ` Thomas Gleixner
2021-09-27 19:26     ` Sohil Mehta
2021-09-13 20:01 ` [RFC PATCH 06/13] x86/uintr: Introduce uintr receiver syscalls Sohil Mehta
2021-09-23 12:26   ` Greg KH
2021-09-24  0:05     ` Thomas Gleixner
2021-09-27 23:20     ` Sohil Mehta
2021-09-28  4:39       ` Greg KH
2021-09-28 16:47         ` Sohil Mehta
2021-09-23 23:52   ` Thomas Gleixner
2021-09-27 23:57     ` Sohil Mehta
2021-09-13 20:01 ` [RFC PATCH 07/13] x86/process/64: Add uintr task context switch support Sohil Mehta
2021-09-24  0:41   ` Thomas Gleixner
2021-09-28  0:30     ` Sohil Mehta
2021-09-13 20:01 ` [RFC PATCH 08/13] x86/process/64: Clean up uintr task fork and exit paths Sohil Mehta
2021-09-24  1:02   ` Thomas Gleixner
2021-09-28  1:23     ` Sohil Mehta
2021-09-13 20:01 ` [RFC PATCH 09/13] x86/uintr: Introduce vector registration and uintr_fd syscall Sohil Mehta
2021-09-24 10:33   ` Thomas Gleixner
2021-09-28 20:40     ` Sohil Mehta
2021-09-13 20:01 ` [RFC PATCH 10/13] x86/uintr: Introduce user IPI sender syscalls Sohil Mehta
2021-09-23 12:28   ` Greg KH
2021-09-28 18:01     ` Sohil Mehta
2021-09-29  7:04       ` Greg KH
2021-09-29 14:27         ` Sohil Mehta
2021-09-24 10:54   ` Thomas Gleixner
2021-09-13 20:01 ` [RFC PATCH 11/13] x86/uintr: Introduce uintr_wait() syscall Sohil Mehta
2021-09-24 11:04   ` Thomas Gleixner
2021-09-25 12:08     ` Thomas Gleixner
2021-09-28 23:13       ` Sohil Mehta
2021-09-28 23:08     ` Sohil Mehta
2021-09-26 14:41   ` Thomas Gleixner
2021-09-29  1:09     ` Sohil Mehta
2021-09-29  3:30   ` Andy Lutomirski [this message]
2021-09-29  4:56     ` Sohil Mehta
2021-09-30 18:08       ` Andy Lutomirski
2021-09-30 19:29         ` Thomas Gleixner
2021-09-30 22:01           ` Andy Lutomirski
2021-10-01  0:01             ` Thomas Gleixner
2021-10-01  4:41               ` Andy Lutomirski
2021-10-01  9:56                 ` Thomas Gleixner
2021-10-01 15:13                   ` Andy Lutomirski
2021-10-01 18:04                     ` Sohil Mehta
2021-10-01 21:29                     ` Thomas Gleixner
2021-10-01 23:00                       ` Sohil Mehta
2021-10-01 23:04                       ` Andy Lutomirski
2021-09-13 20:01 ` [RFC PATCH 12/13] x86/uintr: Wire up the user interrupt syscalls Sohil Mehta
2021-09-13 20:01 ` [RFC PATCH 13/13] selftests/x86: Add basic tests for User IPI Sohil Mehta
2021-09-13 20:27 ` [RFC PATCH 00/13] x86 User Interrupts support Dave Hansen
2021-09-14 19:03   ` Mehta, Sohil
2021-09-23 12:19     ` Greg KH
2021-09-23 14:09       ` Greg KH
2021-09-23 14:46         ` Dave Hansen
2021-09-23 15:07           ` Greg KH
2021-09-23 23:24         ` Sohil Mehta
2021-09-23 23:09       ` Sohil Mehta
2021-09-24  0:17       ` Sohil Mehta
2021-09-23 14:39 ` Jens Axboe
2021-09-29  4:31 ` Andy Lutomirski
2021-09-30 16:30   ` Stefan Hajnoczi
2021-09-30 17:24     ` Sohil Mehta
2021-09-30 17:26       ` Andy Lutomirski
2021-10-01 16:35       ` Stefan Hajnoczi
2021-10-01 16:35         ` Stefan Hajnoczi
2021-10-01 16:41         ` Richard Henderson
2021-10-01 16:41           ` Richard Henderson
2021-09-30 16:26 ` Stefan Hajnoczi
2021-10-01  0:40   ` Sohil Mehta
2021-10-01  8:19 ` Pavel Machek
2021-11-18 22:19   ` Sohil Mehta
2021-11-16  3:49 ` Prakash Sangappa
2021-11-18 21:44   ` Sohil Mehta
2021-12-22 16:17 ` Chrisma Pakha
2022-01-07  2:08   ` Sohil Mehta
2022-01-17  1:14     ` Chrisma Pakha

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=f5a971e4-6b0d-477f-992c-89110a2ceb03@www.fastmail.com \
    --to=luto@kernel.org \
    --cc=arnd@arndb.de \
    --cc=ashok.raj@intel.com \
    --cc=axboe@kernel.dk \
    --cc=bp@alien8.de \
    --cc=christian@brauner.io \
    --cc=corbet@lwn.net \
    --cc=dan.j.williams@intel.com \
    --cc=dave.hansen@intel.com \
    --cc=gayatri.kammela@intel.com \
    --cc=guang.zeng@intel.com \
    --cc=hpa@zytor.com \
    --cc=jacob.jun.pan@linux.intel.com \
    --cc=linux-api@vger.kernel.org \
    --cc=linux-arch@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-kselftest@vger.kernel.org \
    --cc=mingo@redhat.com \
    --cc=peterz@infradead.org \
    --cc=ramesh.thomas@intel.com \
    --cc=randy.e.witt@intel.com \
    --cc=ravi.v.shankar@intel.com \
    --cc=shuah@kernel.org \
    --cc=sohil.mehta@intel.com \
    --cc=tglx@linutronix.de \
    --cc=tony.luck@intel.com \
    --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.