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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>,
	Stefano Stabellini <sstabellini@kernel.org>,
	Julien Grall <julien@xen.org>,
	Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>
Subject: [RFC PATCH 09/10] arm: traps: try to preempt before leaving IRQ handler
Date: Tue, 23 Feb 2021 02:34:58 +0000	[thread overview]
Message-ID: <20210223023428.757694-10-volodymyr_babchuk@epam.com> (raw)
In-Reply-To: <20210223023428.757694-1-volodymyr_babchuk@epam.com>

Now we can try to preempt code that is running in hypervisor code. To
do so we need to try to invoke scheduler by calling try_preempt(),
while not in nested IRQ handler.

Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com>
---
 xen/arch/arm/traps.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 6fa135050b..98a4fb4904 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -2260,7 +2260,14 @@ void do_trap_guest_serror(struct cpu_user_regs *regs)
 
 void do_trap_irq(struct cpu_user_regs *regs)
 {
+    static DEFINE_PER_CPU(unsigned int, irq_entry_cnt);
+
+    this_cpu(irq_entry_cnt)++;
     gic_interrupt(regs, 0);
+    this_cpu(irq_entry_cnt)--;
+
+    if (this_cpu(irq_entry_cnt) == 0)
+        try_preempt(true);
 }
 
 void do_trap_fiq(struct cpu_user_regs *regs)
-- 
2.29.2


  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 ` [RFC PATCH 04/10] preempt: use atomic_t to for preempt_count Volodymyr Babchuk
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 ` Volodymyr Babchuk [this message]
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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