From: "Luck, Tony" <tony.luck@intel.com>
To: Pavel Machek <pavel@denx.de>
Cc: Thomas Gleixner <tglx@linutronix.de>,
"Yu, Fenghua" <fenghua.yu@intel.com>,
"x86@kernel.org" <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"patches@lists.linux.dev" <patches@lists.linux.dev>
Subject: RE: [PATCH v2 1/2] x86/split_lock: Make life miserable for split lockers
Date: Thu, 17 Mar 2022 16:27:41 +0000 [thread overview]
Message-ID: <532e45aad7c64349b52217bc548edaca@intel.com> (raw)
In-Reply-To: <20220317111305.GB2237@amd>
Pavel,
> I'm not sure what split locks are, and if you want applications to
> stop doing that maybe documentation would help.
See existing Documentation/x86/buslock.rst
> Anyway, you can't really introduce regressions to userspace to "get
> stuff fixed" in applications.
Applications can inflict pain on the system with atomic operations
on unaligned operands that cross cache line boundaries. This
is just pushing some pain back to the applications.
An alternate title for this patch series could have been:
"Split-locks: The OS strikes back"
Note that there are few applications that actually split locks.
Normal compiler alignment rules generally avoid them.
Applications that run on non-x86 architectures have to
avoid them because few others allow atomic operations
on unaligned operands.
-Tony
next prev parent reply other threads:[~2022-03-17 16:27 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-17 1:27 [PATCH] x86/split_lock: Make life miserable for split lockers Tony Luck
2022-03-07 22:30 ` Thomas Gleixner
2022-03-08 0:37 ` Luck, Tony
2022-03-08 14:59 ` Thomas Gleixner
2022-03-08 17:12 ` Luck, Tony
2022-03-10 20:48 ` [PATCH v2 0/2] " Tony Luck
2022-03-10 20:48 ` [PATCH v2 1/2] x86/split_lock: " Tony Luck
2022-03-17 11:13 ` Pavel Machek
2022-03-17 16:27 ` Luck, Tony [this message]
2022-03-17 18:06 ` Thomas Gleixner
2022-03-17 22:21 ` David Laight
2022-03-17 22:40 ` Luck, Tony
2022-03-18 12:21 ` Fenghua Yu
2022-04-27 13:49 ` [tip: x86/splitlock] " tip-bot2 for Tony Luck
2022-03-10 20:48 ` [PATCH v2 2/2] x86/split-lock: Remove unused TIF_SLD bit Tony Luck
2022-04-27 13:49 ` [tip: x86/splitlock] " tip-bot2 for Tony Luck
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