From: Peter Zijlstra <peterz@infradead.org>
To: torvalds@linux-foundation.org, will.deacon@arm.com,
oleg@redhat.com, paulmck@linux.vnet.ibm.com,
benh@kernel.crashing.org, mpe@ellerman.id.au, npiggin@gmail.com
Cc: linux-kernel@vger.kernel.org, mingo@kernel.org,
stern@rowland.harvard.edu, peterz@infradead.org
Subject: [RFC][PATCH 5/5] powerpc: Remove SYNC from _switch
Date: Wed, 07 Jun 2017 18:15:06 +0200 [thread overview]
Message-ID: <20170607162013.905320602@infradead.org> (raw)
In-Reply-To: 20170607161501.819948352@infradead.org
[-- Attachment #1: peterz-powerpc-switch-to.patch --]
[-- Type: text/plain, Size: 944 bytes --]
Now that the scheduler's rq->lock is RCsc and thus provides full
transitivity between scheduling actions. And since we cannot migrate
current, a task needs a switch-out and a switch-in in order to
migrate, in which case the RCsc provides all the ordering we need.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/powerpc/kernel/entry_64.S | 8 --------
1 file changed, 8 deletions(-)
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -488,14 +488,6 @@ _GLOBAL(_switch)
std r23,_CCR(r1)
std r1,KSP(r3) /* Set old stack pointer */
-#ifdef CONFIG_SMP
- /* We need a sync somewhere here to make sure that if the
- * previous task gets rescheduled on another CPU, it sees all
- * stores it has performed on this one.
- */
- sync
-#endif /* CONFIG_SMP */
-
/*
* If we optimise away the clear of the reservation in system
* calls because we know the CPU tracks the address of the
next prev parent reply other threads:[~2017-06-07 16:21 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-07 16:15 [RFC][PATCH 0/5] Getting rid of smp_mb__before_spinlock Peter Zijlstra
2017-06-07 16:15 ` [RFC][PATCH 1/5] mm: Rework {set,clear,mm}_tlb_flush_pending() Peter Zijlstra
2017-06-09 14:45 ` Will Deacon
2017-06-09 18:42 ` Peter Zijlstra
2017-07-28 17:45 ` Peter Zijlstra
2017-08-01 10:31 ` Will Deacon
2017-08-01 12:02 ` Benjamin Herrenschmidt
2017-08-01 12:14 ` Peter Zijlstra
2017-08-01 16:39 ` Peter Zijlstra
2017-08-01 16:44 ` Will Deacon
2017-08-01 16:48 ` Peter Zijlstra
2017-08-01 22:59 ` Peter Zijlstra
2017-08-02 1:23 ` Benjamin Herrenschmidt
2017-08-02 8:11 ` Peter Zijlstra
2017-08-02 8:15 ` Will Deacon
2017-08-02 8:43 ` Will Deacon
2017-08-02 8:51 ` Peter Zijlstra
2017-08-02 9:02 ` Will Deacon
2017-08-02 22:54 ` Benjamin Herrenschmidt
2017-08-02 8:45 ` Peter Zijlstra
2017-08-02 9:02 ` Will Deacon
2017-08-02 9:18 ` Peter Zijlstra
2017-08-02 13:57 ` Benjamin Herrenschmidt
2017-08-02 15:46 ` Peter Zijlstra
2017-08-02 0:17 ` Benjamin Herrenschmidt
2017-08-01 22:42 ` Benjamin Herrenschmidt
2017-06-07 16:15 ` [RFC][PATCH 2/5] locking: Introduce smp_mb__after_spinlock() Peter Zijlstra
2017-06-07 16:15 ` [RFC][PATCH 3/5] overlayfs: Remove smp_mb__before_spinlock() usage Peter Zijlstra
2017-06-07 16:15 ` [RFC][PATCH 4/5] locking: Remove smp_mb__before_spinlock() Peter Zijlstra
2017-06-07 16:15 ` Peter Zijlstra [this message]
2017-06-08 0:32 ` [RFC][PATCH 5/5] powerpc: Remove SYNC from _switch Nicholas Piggin
2017-06-08 6:54 ` Peter Zijlstra
2017-06-08 7:29 ` Nicholas Piggin
2017-06-08 7:57 ` Peter Zijlstra
2017-06-08 8:21 ` Nicholas Piggin
2017-06-08 9:54 ` Michael Ellerman
2017-06-08 10:00 ` Nicholas Piggin
2017-06-08 12:45 ` Peter Zijlstra
2017-06-08 13:18 ` Nicholas Piggin
2017-06-08 13:47 ` Peter Zijlstra
2017-06-09 14:49 ` [RFC][PATCH 0/5] Getting rid of smp_mb__before_spinlock Will Deacon
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