From: "Jan Beulich" <JBeulich@suse.com>
To: xen-devel <xen-devel@lists.xenproject.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Subject: [PATCH 5/5] x86: place non-parked CPUs into wait-for-SIPI state after offlining
Date: Wed, 01 Aug 2018 08:33:52 -0600 [thread overview]
Message-ID: <5B61C4D002000078001D9F92@prv1-mh.provo.novell.com> (raw)
In-Reply-To: <5B61C21202000078001D9F2D@prv1-mh.provo.novell.com>
This is presumably more power efficient than keeping them in a HLT loop,
and I supposed also the state in which they're being handed off by
firmware.
Split off from wakeup_secondary_cpu() the code to assert/deassert INIT
(and in turn also recurring wait-for-send-completion code), and re-use
it from __cpu_die(). Take the opportunity and add the previously
missing apic_wait_icr_idle() at the start of the sequence.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/arch/x86/smpboot.c
+++ b/xen/arch/x86/smpboot.c
@@ -415,10 +415,25 @@ void start_secondary(void *unused)
extern void *stack_start;
-static int wakeup_secondary_cpu(int phys_apicid, unsigned long start_eip)
+static unsigned int wait_send(void)
{
- unsigned long send_status = 0, accept_status = 0;
- int maxlvt, timeout, i;
+ unsigned int send_status, timeout = 0;
+
+ Dprintk("Waiting for send to finish...\n");
+ do {
+ Dprintk("+");
+ udelay(100);
+ send_status = apic_read(APIC_ICR) & APIC_ICR_BUSY;
+ } while ( send_status && (timeout++ < 1000) );
+
+ return send_status;
+}
+
+static unsigned int init_secondary_cpu(unsigned int phys_apicid)
+{
+ unsigned int send_status = 0;
+
+ apic_wait_icr_idle();
/*
* Be paranoid about clearing APIC errors.
@@ -436,13 +451,7 @@ static int wakeup_secondary_cpu(int phys
if ( !x2apic_enabled )
{
- Dprintk("Waiting for send to finish...\n");
- timeout = 0;
- do {
- Dprintk("+");
- udelay(100);
- send_status = apic_read(APIC_ICR) & APIC_ICR_BUSY;
- } while ( send_status && (timeout++ < 1000) );
+ send_status = wait_send();
mdelay(10);
@@ -450,13 +459,7 @@ static int wakeup_secondary_cpu(int phys
apic_icr_write(APIC_INT_LEVELTRIG | APIC_DM_INIT, phys_apicid);
- Dprintk("Waiting for send to finish...\n");
- timeout = 0;
- do {
- Dprintk("+");
- udelay(100);
- send_status = apic_read(APIC_ICR) & APIC_ICR_BUSY;
- } while ( send_status && (timeout++ < 1000) );
+ send_status = wait_send();
}
else if ( tboot_in_measured_env() )
{
@@ -471,7 +474,16 @@ static int wakeup_secondary_cpu(int phys
udelay(10);
}
- maxlvt = get_maxlvt();
+ return send_status;
+}
+
+static unsigned int wakeup_secondary_cpu(unsigned int phys_apicid,
+ unsigned int start_eip)
+{
+ unsigned int send_status, accept_status = 0;
+ unsigned int maxlvt = get_maxlvt(), i;
+
+ send_status = init_secondary_cpu(phys_apicid);
for ( i = 0; i < 2; i++ )
{
@@ -491,15 +503,9 @@ static int wakeup_secondary_cpu(int phys
/* Give the other CPU some time to accept the IPI. */
udelay(300);
- Dprintk("Startup point 1.\n");
+ Dprintk("Startup point %u.\n", i + 1);
- Dprintk("Waiting for send to finish...\n");
- timeout = 0;
- do {
- Dprintk("+");
- udelay(100);
- send_status = apic_read(APIC_ICR) & APIC_ICR_BUSY;
- } while ( send_status && (timeout++ < 1000) );
+ send_status = wait_send();
/* Give the other CPU some time to accept the IPI. */
udelay(200);
@@ -519,7 +525,7 @@ static int wakeup_secondary_cpu(int phys
if ( send_status )
printk("APIC never delivered???\n");
if ( accept_status )
- printk("APIC delivery error (%lx).\n", accept_status);
+ printk("APIC delivery error (%x).\n", accept_status);
return (send_status | accept_status);
}
@@ -1238,6 +1244,9 @@ void __cpu_die(unsigned int cpu)
if ( (++i % 10) == 0 )
printk(KERN_ERR "CPU %u still not dead...\n", cpu);
}
+
+ if ( !park_offline_cpus )
+ init_secondary_cpu(x86_cpu_to_apicid[cpu]);
}
int cpu_add(uint32_t apic_id, uint32_t acpi_id, uint32_t pxm)
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next prev parent reply other threads:[~2018-08-01 14:33 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-01 14:22 [PATCH 0/5] x86: more power-efficient CPU parking Jan Beulich
2018-08-01 14:31 ` [PATCH 1/5] x86/cpuidle: replace a pointless NULL check Jan Beulich
2018-08-01 14:33 ` Andrew Cooper
2018-08-01 15:12 ` Jan Beulich
2018-08-01 14:31 ` [PATCH 2/5] x86/idle: re-arrange dead-idle handling Jan Beulich
2018-09-07 17:08 ` Andrew Cooper
2018-09-10 10:13 ` Jan Beulich
2018-10-26 10:55 ` Ping: " Jan Beulich
2018-12-05 20:33 ` Andrew Cooper
2018-12-06 8:16 ` Jan Beulich
2018-08-01 14:32 ` [PATCH 3/5] x86/cpuidle: push parked CPUs into deeper sleep states when possible Jan Beulich
2018-10-26 10:56 ` Ping: " Jan Beulich
2018-08-01 14:33 ` [PATCH 4/5] x86/cpuidle: clean up Cx dumping Jan Beulich
2018-08-01 14:40 ` Andrew Cooper
2018-08-01 14:33 ` Jan Beulich [this message]
2018-08-29 7:08 ` Ping: [PATCH 0/5] x86: more power-efficient CPU parking Jan Beulich
2018-08-29 17:01 ` Andrew Cooper
2018-08-30 7:29 ` Jan Beulich
[not found] ` <5B61C21202000000000FC1F1@prv1-mh.provo.novell.com>
[not found] ` <5B61C21202000078001F8805@prv1-mh.provo.novell.com>
[not found] ` <5B61C21202000000000FC6BD@prv1-mh.provo.novell.com>
[not found] ` <5B61C212020000780020B6D8@prv1-mh.provo.novell.com>
[not found] ` <5B61C21202000000000FF27E@prv1-mh.provo.novell.com>
[not found] ` <5B61C2120200007800224310@prv1-mh.provo.novell.com>
2019-04-03 10:12 ` Jan Beulich
2019-04-03 11:14 ` Andrew Cooper
2019-04-03 12:43 ` Jan Beulich
2019-04-03 14:44 ` Andrew Cooper
2019-04-03 15:20 ` Jan Beulich
[not found] ` <5B61C2120200000000101EDC@prv1-mh.provo.novell.com>
[not found] ` <5B61C212020000780022FF0D@prv1-mh.provo.novell.com>
2019-05-17 10:10 ` [PATCH v2 0/3] " Jan Beulich
2019-05-17 10:10 ` [Xen-devel] " Jan Beulich
2019-05-17 10:11 ` [PATCH v2 1/3] x86/idle: re-arrange dead-idle handling Jan Beulich
2019-05-17 10:11 ` [Xen-devel] " Jan Beulich
2019-05-20 14:25 ` Andrew Cooper
2019-05-20 14:25 ` [Xen-devel] " Andrew Cooper
2019-05-17 10:12 ` [PATCH v2 2/3] x86/cpuidle: push parked CPUs into deeper sleep states when possible Jan Beulich
2019-05-17 10:12 ` [Xen-devel] " Jan Beulich
2019-05-17 10:12 ` [PATCH v2 3/3] x86/cpuidle: clean up Cx dumping Jan Beulich
2019-05-17 10:12 ` [Xen-devel] " Jan Beulich
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