From: Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>
To: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Cc: Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
George Dunlap <george.dunlap@citrix.com>,
Ian Jackson <iwj@xenproject.org>, Jan Beulich <jbeulich@suse.com>,
Julien Grall <julien@xen.org>,
Stefano Stabellini <sstabellini@kernel.org>, Wei Liu <wl@xen.org>
Subject: [RFC PATCH 04/10] preempt: use atomic_t to for preempt_count
Date: Tue, 23 Feb 2021 02:34:56 +0000 [thread overview]
Message-ID: <20210223023428.757694-5-volodymyr_babchuk@epam.com> (raw)
In-Reply-To: <20210223023428.757694-1-volodymyr_babchuk@epam.com>
This ensures that preempt_count will be accounted correctly
during in-hypevisor context switches.
Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com>
---
xen/common/preempt.c | 6 +++---
xen/include/xen/preempt.h | 9 ++++-----
2 files changed, 7 insertions(+), 8 deletions(-)
diff --git a/xen/common/preempt.c b/xen/common/preempt.c
index 3b4178fd44..ad61c8419a 100644
--- a/xen/common/preempt.c
+++ b/xen/common/preempt.c
@@ -23,17 +23,17 @@
#include <xen/irq.h>
#include <asm/system.h>
-DEFINE_PER_CPU(unsigned int, __preempt_count);
+DEFINE_PER_CPU(atomic_t, __preempt_count);
bool_t in_atomic(void)
{
- return preempt_count() || in_irq() || !local_irq_is_enabled();
+ return atomic_read(&preempt_count()) || in_irq() || local_irq_is_enabled();
}
#ifndef NDEBUG
void ASSERT_NOT_IN_ATOMIC(void)
{
- ASSERT(!preempt_count());
+ ASSERT(!atomic_read(&preempt_count()));
ASSERT(!in_irq());
ASSERT(local_irq_is_enabled());
}
diff --git a/xen/include/xen/preempt.h b/xen/include/xen/preempt.h
index bef83135a1..e217900d6e 100644
--- a/xen/include/xen/preempt.h
+++ b/xen/include/xen/preempt.h
@@ -9,21 +9,20 @@
#ifndef __XEN_PREEMPT_H__
#define __XEN_PREEMPT_H__
+#include <asm/atomic.h>
#include <xen/types.h>
#include <xen/percpu.h>
-DECLARE_PER_CPU(unsigned int, __preempt_count);
+DECLARE_PER_CPU(atomic_t, __preempt_count);
#define preempt_count() (this_cpu(__preempt_count))
#define preempt_disable() do { \
- preempt_count()++; \
- barrier(); \
+ atomic_inc(&preempt_count()); \
} while (0)
#define preempt_enable() do { \
- barrier(); \
- preempt_count()--; \
+ atomic_dec(&preempt_count()); \
} while (0)
bool_t in_atomic(void);
--
2.29.2
next prev parent reply other threads:[~2021-02-23 2:35 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-23 2:34 [RFC PATCH 00/10] Preemption in hypervisor (ARM only) Volodymyr Babchuk
2021-02-23 2:34 ` [RFC PATCH 01/10] sched: core: save IRQ state during locking Volodymyr Babchuk
2021-02-23 8:52 ` Jürgen Groß
2021-02-23 11:15 ` Volodymyr Babchuk
2021-02-24 18:29 ` Andrew Cooper
2021-02-23 2:34 ` [RFC PATCH 03/10] sched: credit2: " Volodymyr Babchuk
2021-02-23 2:34 ` [RFC PATCH 02/10] sched: rt: " Volodymyr Babchuk
2021-02-23 2:34 ` Volodymyr Babchuk [this message]
2021-02-23 2:34 ` [RFC PATCH 05/10] preempt: add try_preempt() function Volodymyr Babchuk
2021-02-23 2:34 ` [RFC PATCH 07/10] sched: core: remove ASSERT_NOT_IN_ATOMIC and disable preemption[!] Volodymyr Babchuk
2021-02-23 2:34 ` [RFC PATCH 06/10] arm: setup: disable preemption during startup Volodymyr Babchuk
2021-02-23 2:34 ` [RFC PATCH 08/10] arm: context_switch: allow to run with IRQs already disabled Volodymyr Babchuk
2021-02-23 2:34 ` [RFC PATCH 10/10] [HACK] alloc pages: enable preemption early Volodymyr Babchuk
2021-02-23 2:34 ` [RFC PATCH 09/10] arm: traps: try to preempt before leaving IRQ handler Volodymyr Babchuk
2021-02-23 9:02 ` [RFC PATCH 00/10] Preemption in hypervisor (ARM only) Julien Grall
2021-02-23 12:06 ` Volodymyr Babchuk
2021-02-24 10:08 ` Julien Grall
2021-02-24 20:57 ` Volodymyr Babchuk
2021-02-24 22:31 ` Julien Grall
2021-02-24 23:58 ` Volodymyr Babchuk
2021-02-25 0:39 ` Andrew Cooper
2021-02-25 12:51 ` Volodymyr Babchuk
2021-03-05 9:31 ` Volodymyr Babchuk
2021-02-24 18:07 ` Andrew Cooper
2021-02-24 23:37 ` Volodymyr Babchuk
2021-03-01 14:39 ` George Dunlap
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