From: Nicholas Piggin <npiggin@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: linux-arch@vger.kernel.org, "Michal Suchánek" <msuchanek@suse.de>,
"Peter Zijlstra" <peterz@infradead.org>,
"Boqun Feng" <boqun.feng@gmail.com>,
linux-kernel@vger.kernel.org,
"Nicholas Piggin" <npiggin@gmail.com>,
virtualization@lists.linux-foundation.org,
"Ingo Molnar" <mingo@redhat.com>,
kvm-ppc@vger.kernel.org, "Waiman Long" <longman@redhat.com>,
"Will Deacon" <will@kernel.org>
Subject: [PATCH v4 6/6] powerpc: implement smp_cond_load_relaxed
Date: Fri, 24 Jul 2020 23:14:23 +1000 [thread overview]
Message-ID: <20200724131423.1362108-7-npiggin@gmail.com> (raw)
In-Reply-To: <20200724131423.1362108-1-npiggin@gmail.com>
This implements smp_cond_load_relaed with the slowpath busy loop using the
preferred SMT priority pattern.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/include/asm/barrier.h | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/arch/powerpc/include/asm/barrier.h b/arch/powerpc/include/asm/barrier.h
index 123adcefd40f..9b4671d38674 100644
--- a/arch/powerpc/include/asm/barrier.h
+++ b/arch/powerpc/include/asm/barrier.h
@@ -76,6 +76,20 @@ do { \
___p1; \
})
+#define smp_cond_load_relaxed(ptr, cond_expr) ({ \
+ typeof(ptr) __PTR = (ptr); \
+ __unqual_scalar_typeof(*ptr) VAL; \
+ VAL = READ_ONCE(*__PTR); \
+ if (unlikely(!(cond_expr))) { \
+ spin_begin(); \
+ do { \
+ VAL = READ_ONCE(*__PTR); \
+ } while (!(cond_expr)); \
+ spin_end(); \
+ } \
+ (typeof(*ptr))VAL; \
+})
+
#ifdef CONFIG_PPC_BOOK3S_64
#define NOSPEC_BARRIER_SLOT nop
#elif defined(CONFIG_PPC_FSL_BOOK3E)
--
2.23.0
next prev parent reply other threads:[~2020-07-24 13:41 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-24 13:14 [PATCH v4 0/6] powerpc: queued spinlocks and rwlocks Nicholas Piggin
2020-07-24 13:14 ` [PATCH v4 1/6] powerpc/pseries: move some PAPR paravirt functions to their own file Nicholas Piggin
2020-07-24 13:14 ` [PATCH v4 2/6] powerpc: move spinlock implementation to simple_spinlock Nicholas Piggin
2020-07-24 13:14 ` [PATCH v4 3/6] powerpc/64s: implement queued spinlocks and rwlocks Nicholas Piggin
2020-07-24 13:14 ` [PATCH v4 4/6] powerpc/pseries: implement paravirt qspinlocks for SPLPAR Nicholas Piggin
2020-07-24 13:14 ` [PATCH v4 5/6] powerpc/qspinlock: optimised atomic_try_cmpxchg_lock that adds the lock hint Nicholas Piggin
2020-07-24 13:14 ` Nicholas Piggin [this message]
2020-07-24 21:10 ` [PATCH v4 6/6] powerpc: implement smp_cond_load_relaxed Waiman Long
2020-07-24 21:11 ` [PATCH v4 0/6] powerpc: queued spinlocks and rwlocks Waiman Long
2020-07-27 7:26 ` Michael Ellerman
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