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From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Peter Oskolkov <posk@google.com>
Cc: linux-kernel@vger.kernel.org,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Peter Zijlstra <peterz@infradead.org>,
	"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
	Boqun Feng <boqun.feng@gmail.com>,
	Andrew Hunter <ahh@google.com>,
	Maged Michael <maged.michael@gmail.com>,
	gromer@google.com,
	Avi Kivity <avi@scylladb.com>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>
Subject: [RFC PATCH 0/2] Introduce serialized smp_call_function APIs
Date: Wed, 13 Mar 2024 16:56:20 -0400
Message-Id: <20240313205622.2179659-1-mathieu.desnoyers@efficios.com>
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commit 944d5fe50f3f ("sched/membarrier: reduce the ability to hammer on sys_membarrier")
introduces a mutex over all membarrier operations to reduce its ability
to slow down the rest of the system.

This RFC series has two objectives:

1) Move this mutex to the smp_call_function APIs so other system calls
   using smp_call_function IPIs are limited in the same way,

2) Restore scalability of MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ with
   MEMBARRIER_CMD_FLAG_CPU, which targets specific CPUs with IPIs.
   This may or may not be useful, and I would welcome benchmarks from
   users of this feature to figure out if this is worth it.

This series applies on top of v6.8.

Thanks,

Mathieu

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Andrew Hunter <ahh@google.com>
Cc: Maged Michael <maged.michael@gmail.com>
Cc: gromer@google.com
Cc: Avi Kivity <avi@scylladb.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Peter Oskolkov <posk@google.com>

Mathieu Desnoyers (2):
  smp: Implement serialized smp_call_function APIs
  sched/membarrier: Use serialized smp_call_function APIs

 include/linux/smp.h       |  40 ++++++++++++++
 kernel/sched/membarrier.c |  24 +++------
 kernel/smp.c              | 106 +++++++++++++++++++++++++++++++++-----
 3 files changed, 141 insertions(+), 29 deletions(-)

-- 
2.39.2