linux-kernel - [patch 03/19] sched/mmcid: Cacheline align MM CID storage

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20251015172834.504490216@linutronix.de>
Date: Wed, 15 Oct 2025 19:29:29 +0200 (CEST)
From: Thomas Gleixner <tglx@...utronix.de>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Peter Zijlstra <peterz@...radead.org>,
 Gabriele Monaco <gmonaco@...hat.com>,
 Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
 Michael Jeanson <mjeanson@...icios.com>,
 Jens Axboe <axboe@...nel.dk>,
 "Paul E. McKenney" <paulmck@...nel.org>,
 "Gautham R. Shenoy" <gautham.shenoy@....com>,
 Florian Weimer <fweimer@...hat.com>,
 Tim Chen <tim.c.chen@...el.com>,
 TCMalloc Team <tcmalloc-eng@...gle.com>
Subject: [patch 03/19] sched/mmcid: Cacheline align MM CID storage

Both the per CPU storage and the data in mm_struct are heavily used in
context switch. As they can end up next to other frequently modified data,
they are subject to false sharing.

Make them cache line aligned.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
 include/linux/rseq_types.h |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/include/linux/rseq_types.h
+++ b/include/linux/rseq_types.h
@@ -112,7 +112,7 @@ struct sched_mm_cid {
  */
 struct mm_cid_pcpu {
 	unsigned int	cid;
-};
+}____cacheline_aligned_in_smp;

 /**
  * struct mm_mm_cid - Storage for per MM CID data
@@ -126,7 +126,7 @@ struct mm_mm_cid {
 	struct mm_cid_pcpu	__percpu *pcpu;
 	unsigned int		nr_cpus_allowed;
 	raw_spinlock_t		lock;
-};
+}____cacheline_aligned_in_smp;
 #else /* CONFIG_SCHED_MM_CID */
 struct mm_cid { };
 struct sched_mm_cid { };