From: Miroslav Benes <mbenes@suse.cz>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jessica Yu <jeyu@redhat.com>, Jiri Kosina <jikos@kernel.org>,
Petr Mladek <pmladek@suse.com>,
linux-kernel@vger.kernel.org, live-patching@vger.kernel.org,
Michael Ellerman <mpe@ellerman.id.au>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
x86@kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-s390@vger.kernel.org, Vojtech Pavlik <vojtech@suse.com>,
Jiri Slaby <jslaby@suse.cz>,
Chris J Arges <chris.j.arges@canonical.com>,
Andy Lutomirski <luto@kernel.org>, Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>,
Balbir Singh <bsingharora@gmail.com>
Subject: Re: [PATCH v4 14/15] livepatch: add /proc/<pid>/patch_state
Date: Tue, 31 Jan 2017 15:31:39 +0100 (CET) [thread overview]
Message-ID: <alpine.LSU.2.20.1701311518290.3719@pobox.suse.cz> (raw)
In-Reply-To: <2c3b793fc23910f8fe15033b2b35e53b0b5dbaf3.1484839971.git.jpoimboe@redhat.com>
On Thu, 19 Jan 2017, Josh Poimboeuf wrote:
> Expose the per-task patch state value so users can determine which tasks
> are holding up completion of a patching operation.
>
> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
> Reviewed-by: Petr Mladek <pmladek@suse.com>
> Reviewed-by: Miroslav Benes <mbenes@suse.cz>
> ---
> Documentation/filesystems/proc.txt | 18 ++++++++++++++++++
> fs/proc/base.c | 15 +++++++++++++++
> 2 files changed, 33 insertions(+)
>
> diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
> index 72624a1..85c501b 100644
> --- a/Documentation/filesystems/proc.txt
> +++ b/Documentation/filesystems/proc.txt
> @@ -44,6 +44,7 @@ Table of Contents
> 3.8 /proc/<pid>/fdinfo/<fd> - Information about opened file
> 3.9 /proc/<pid>/map_files - Information about memory mapped files
> 3.10 /proc/<pid>/timerslack_ns - Task timerslack value
> + 3.11 /proc/<pid>/patch_state - Livepatch patch operation state
>
> 4 Configuring procfs
> 4.1 Mount options
> @@ -1886,6 +1887,23 @@ Valid values are from 0 - ULLONG_MAX
> An application setting the value must have PTRACE_MODE_ATTACH_FSCREDS level
> permissions on the task specified to change its timerslack_ns value.
>
> +3.11 /proc/<pid>/patch_state - Livepatch patch operation state
> +-----------------------------------------------------------------
> +When CONFIG_LIVEPATCH is enabled, this file displays the value of the
> +patch state for the task.
> +
> +A value of '-1' indicates that no patch is in transition.
> +
> +A value of '0' indicates that a patch is in transition and the task is
> +unpatched. If the patch is being enabled, then the task hasn't been
> +patched yet. If the patch is being disabled, then the task has already
> +been unpatched.
> +
> +A value of '1' indicates that a patch is in transition and the task is
> +patched. If the patch is being enabled, then the task has already been
> +patched. If the patch is being disabled, then the task hasn't been
> +unpatched yet.
> +
Despite my review I thought about this some more. I think the logic make
sense internally but when exposed it can be confusing. We do not export
klp_target_state value, so users have to know if a patch is being enabled
or disabled. Of course, they should know that, but I guess they'd like to
use an userspace tool for this. Such tool needs to look at
/proc/<pid>/patch_state to find out which tasks are blocking the
completion and that is it. No more information anywhere.
We can either export klp_target_state, or change /proc/<pid>/patch_state
to show only two states - task is in transition (1), task is patched (0).
What do you think?
Miroslav
next prev parent reply other threads:[~2017-01-31 14:31 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-19 15:46 [PATCH v4 00/15] livepatch: hybrid consistency model Josh Poimboeuf
2017-01-19 15:46 ` [PATCH v4 01/15] stacktrace/x86: add function for detecting reliable stack traces Josh Poimboeuf
2017-01-26 13:56 ` Petr Mladek
2017-01-26 17:57 ` Josh Poimboeuf
2017-01-27 8:47 ` Miroslav Benes
2017-01-27 17:13 ` Josh Poimboeuf
2017-02-01 19:57 ` [PATCH v4.1 " Josh Poimboeuf
2017-02-02 14:39 ` Miroslav Benes
2017-01-19 15:46 ` [PATCH v4 02/15] x86/entry: define _TIF_ALLWORK_MASK flags explicitly Josh Poimboeuf
2017-01-19 15:46 ` [PATCH v4 03/15] livepatch: create temporary klp_update_patch_state() stub Josh Poimboeuf
2017-01-27 8:52 ` Miroslav Benes
2017-01-19 15:46 ` [PATCH v4 04/15] livepatch/x86: add TIF_PATCH_PENDING thread flag Josh Poimboeuf
2017-01-19 15:46 ` [PATCH v4 05/15] livepatch/powerpc: " Josh Poimboeuf
2017-01-19 15:46 ` [PATCH v4 06/15] livepatch/s390: reorganize TIF thread flag bits Josh Poimboeuf
2017-01-19 15:46 ` [PATCH v4 07/15] livepatch/s390: add TIF_PATCH_PENDING thread flag Josh Poimboeuf
2017-01-19 15:46 ` [PATCH v4 08/15] livepatch: separate enabled and patched states Josh Poimboeuf
2017-01-19 15:46 ` [PATCH v4 09/15] livepatch: remove unnecessary object loaded check Josh Poimboeuf
2017-01-19 15:46 ` [PATCH v4 10/15] livepatch: move patching functions into patch.c Josh Poimboeuf
2017-01-19 15:46 ` [PATCH v4 11/15] livepatch: use kstrtobool() in enabled_store() Josh Poimboeuf
2017-01-19 15:46 ` [PATCH v4 12/15] livepatch: store function sizes Josh Poimboeuf
2017-01-19 15:46 ` [PATCH v4 13/15] livepatch: change to a per-task consistency model Josh Poimboeuf
2017-02-02 11:45 ` Petr Mladek
2017-02-02 11:47 ` Petr Mladek
2017-02-02 11:51 ` Petr Mladek
2017-02-03 16:21 ` Miroslav Benes
2017-02-03 20:39 ` Josh Poimboeuf
2017-02-06 16:44 ` Petr Mladek
2017-02-06 19:51 ` Josh Poimboeuf
2017-02-08 15:47 ` Petr Mladek
2017-02-08 16:46 ` Josh Poimboeuf
2017-02-09 10:24 ` Petr Mladek
2017-02-03 16:41 ` Miroslav Benes
2017-02-06 15:58 ` Josh Poimboeuf
2017-02-07 8:21 ` Miroslav Benes
2017-01-19 15:46 ` [PATCH v4 14/15] livepatch: add /proc/<pid>/patch_state Josh Poimboeuf
2017-01-31 14:31 ` Miroslav Benes [this message]
2017-01-31 14:56 ` Josh Poimboeuf
2017-02-01 8:54 ` Miroslav Benes
2017-01-19 15:46 ` [PATCH v4 15/15] livepatch: allow removal of a disabled patch Josh Poimboeuf
2017-02-03 16:48 ` Miroslav Benes
2017-02-01 20:02 ` [PATCH v4 00/15] livepatch: hybrid consistency model Josh Poimboeuf
2017-02-01 20:52 ` Miroslav Benes
2017-02-01 21:01 ` Jiri Kosina
2017-02-02 14:37 ` Petr Mladek
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