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[IA64] kdump: Short path to freeze CPUs 

Setting monarch_cpu = -1 to let slaves frozen might not work, because
there might be slaves being late, not entered the rendezvous yet.
Such slaves might be caught in while (monarch_cpu == -1) loop.

Use kdump_in_progress instead of monarch_cpus to break INIT rendezvous
and let all slaves enter DIE_INIT_SLAVE_LEAVE smoothly.

And monarch no longer need to manage rendezvous if once kdump_in_progress
is set, catch the monarch in DIE_INIT_MONARCH_ENTER then.

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Haren Myneni <hbabu@us.ibm.com>
Cc: kexec@lists.infradead.org
Acked-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This commit is contained in:
Hidetoshi Seto 2009-08-06 14:51:58 -07:00 committed by Tony Luck
parent 5959906ee9
commit 0cced40e7c
2 changed files with 19 additions and 11 deletions
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15
arch/ia64/kernel/crash.c
View File

@ -127,14 +127,13 @@ machine_crash_shutdown(struct pt_regs *pt)
* If an INIT is asserted here:
* - All receivers might be slaves, since some of cpus could already
* be frozen and INIT might be masked on monarch. In this case,
* all slaves will park in while (monarch_cpu == -1) loop before
* DIE_INIT_SLAVE_ENTER that for waiting monarch enters.
* => TBD: freeze all slaves
* all slaves will be frozen soon since kdump_in_progress will let
* them into DIE_INIT_SLAVE_LEAVE.
* - One might be a monarch, but INIT rendezvous will fail since
* at least this cpu already have INIT masked so it never join
* to the rendezvous. In this case, all slaves and monarch will
* be frozen after timeout of the INIT rendezvous.
* => TBD: freeze them without waiting timeout
* be frozen soon with no wait since the INIT rendezvous is skipped
* by kdump_in_progress.
*/
kdump_smp_send_stop();
/* not all cpu response to IPI, send INIT to freeze them */
@ -187,6 +186,7 @@ kdump_init_notifier(struct notifier_block *self, unsigned long val, void *data)
break;
/* fall through */
case DIE_INIT_SLAVE_LEAVE:
case DIE_INIT_MONARCH_ENTER:
case DIE_MCA_RENDZVOUS_LEAVE:
unw_init_running(kdump_cpu_freeze, NULL);
break;
@ -217,7 +217,6 @@ kdump_init_notifier(struct notifier_block *self, unsigned long val, void *data)
if (kdump_on_init && (nd->sos->rv_rc != 1)) {
if (atomic_inc_return(&kdump_in_progress) != 1)
kdump_freeze_monarch = 1;
*(nd->monarch_cpu) = -1;
}
break;
case DIE_INIT_MONARCH_LEAVE:
@ -228,10 +227,8 @@ kdump_init_notifier(struct notifier_block *self, unsigned long val, void *data)
case DIE_MCA_MONARCH_LEAVE:
/* *(nd->data) indicate if MCA is recoverable */
if (kdump_on_fatal_mca && !(*(nd->data))) {
if (atomic_inc_return(&kdump_in_progress) == 1) {
*(nd->monarch_cpu) = -1;
if (atomic_inc_return(&kdump_in_progress) == 1)
machine_kdump_on_init();
}
/* We got fatal MCA while kdump!? No way!! */
}
break;

15
arch/ia64/kernel/mca.c
View File

@ -1682,14 +1682,25 @@ ia64_init_handler(struct pt_regs *regs, struct switch_stack *sw,
if (!sos->monarch) {
ia64_mc_info.imi_rendez_checkin[cpu] = IA64_MCA_RENDEZ_CHECKIN_INIT;
#ifdef CONFIG_KEXEC
while (monarch_cpu == -1 && !atomic_read(&kdump_in_progress))
udelay(1000);
#else
while (monarch_cpu == -1)
cpu_relax(); /* spin until monarch enters */
cpu_relax(); /* spin until monarch enters */
#endif
NOTIFY_INIT(DIE_INIT_SLAVE_ENTER, regs, (long)&nd, 1);
NOTIFY_INIT(DIE_INIT_SLAVE_PROCESS, regs, (long)&nd, 1);
#ifdef CONFIG_KEXEC
while (monarch_cpu != -1 && !atomic_read(&kdump_in_progress))
udelay(1000);
#else
while (monarch_cpu != -1)
cpu_relax(); /* spin until monarch leaves */
cpu_relax(); /* spin until monarch leaves */
#endif
NOTIFY_INIT(DIE_INIT_SLAVE_LEAVE, regs, (long)&nd, 1);