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Subject[PATCH][2.5][4/5] CPU Hotplug mm/
 slab.c   |   39 +++++++++++++++++++++++++++++++++++++++
vmscan.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 83 insertions(+)

Index: linux-2.5.61-trojan/mm/slab.c
===================================================================
RCS file: /build/cvsroot/linux-2.5.61/mm/slab.c,v
retrieving revision 1.1.1.1
diff -u -r1.1.1.1 slab.c
--- linux-2.5.61-trojan/mm/slab.c 15 Feb 2003 12:32:45 -0000 1.1.1.1
+++ linux-2.5.61-trojan/mm/slab.c 17 Feb 2003 05:32:26 -0000
@@ -464,6 +464,7 @@
} g_cpucache_up;

static struct timer_list reap_timers[NR_CPUS];
+static unsigned long stop_reap_timer_mask;

static void reap_timer_fnc(unsigned long data);

@@ -523,10 +524,20 @@
init_timer(rt);
rt->expires = jiffies + HZ + 3*cpu;
rt->function = reap_timer_fnc;
+ clear_bit(cpu, &stop_reap_timer_mask);
add_timer_on(rt, cpu);
}
}

+static void stop_cpu_timer(int cpu)
+{
+ struct timer_list *rt = &reap_timers[cpu];
+
+ set_bit(cpu, &stop_reap_timer_mask);
+ while (rt->function)
+ cpu_relax();
+}
+
/*
* Note: if someone calls kmem_cache_alloc() on the new
* cpu before the cpuup callback had a chance to allocate
@@ -583,6 +594,26 @@
}
up(&cache_chain_sem);
break;
+ case CPU_OFFLINE:
+ stop_cpu_timer(cpu);
+ break;
+
+ case CPU_DEAD:
+ down(&cache_chain_sem);
+ list_for_each(p, &cache_chain) {
+ struct array_cache *nc;
+
+ kmem_cache_t* cachep = list_entry(p, kmem_cache_t, next);
+ spin_lock_irq(&cachep->spinlock);
+ nc = cachep->array[cpu];
+ cachep->array[cpu] = NULL;
+ cachep->free_limit = (num_online_cpus())*cachep->batchcount
+ + cachep->num;
+ kfree(nc);
+ spin_unlock_irq(&cachep->spinlock);
+ }
+ up(&cache_chain_sem);
+ break;
}
return NOTIFY_OK;
bad:
@@ -1235,6 +1266,9 @@
}
{
int i;
+ /* no cpu_online check required here since we clear the percpu
+ * array on cpu offline and set this to NULL.
+ */
for (i = 0; i < NR_CPUS; i++)
kfree(cachep->array[i]);
/* NUMA: free the list3 structures */
@@ -2183,6 +2217,11 @@
int cpu = smp_processor_id();
struct timer_list *rt = &reap_timers[cpu];

+ if (unlikely(test_bit(cpu, &stop_reap_timer_mask))) {
+ del_timer(rt);
+ rt->function = NULL;
+ return;
+ }
cache_reap();
mod_timer(rt, jiffies + REAPTIMEOUT_CPUC + cpu);
}
Index: linux-2.5.61-trojan/mm/vmscan.c
===================================================================
RCS file: /build/cvsroot/linux-2.5.61/mm/vmscan.c,v
retrieving revision 1.1.1.1
diff -u -r1.1.1.1 vmscan.c
--- linux-2.5.61-trojan/mm/vmscan.c 15 Feb 2003 12:32:45 -0000 1.1.1.1
+++ linux-2.5.61-trojan/mm/vmscan.c 17 Feb 2003 06:47:05 -0000
@@ -27,6 +27,7 @@
#include <linux/pagevec.h>
#include <linux/backing-dev.h>
#include <linux/rmap-locking.h>
+#include <linux/notifier.h>

#include <asm/pgalloc.h>
#include <asm/tlbflush.h>
@@ -931,6 +932,7 @@
daemonize("kswapd%d", pgdat->node_id);
set_cpus_allowed(tsk, node_to_cpumask(pgdat->node_id));

+ printk("Set %s affinity to %08lX\n", tsk->comm, tsk->cpus_allowed);
/*
* Tell the memory management that we're a "memory allocator",
* and that if we need more memory we should get access to it
@@ -996,6 +998,47 @@
}
#endif

+/* It's optimal to keep kswapds on the same CPUs as their memory, but
+ not required for correctness. So if the last cpu in a node goes
+ away, let them run anywhere, and as the first one comes back,
+ restore their cpu bindings. */
+static int __devinit cpu_callback(struct notifier_block *nfb,
+ unsigned long action,
+ void *hcpu)
+{
+#if defined(CONFIG_HOTPLUG) && defined(CONFIG_SMP)
+ pg_data_t *pgdat;
+ unsigned int hotcpu = (unsigned long)hcpu;
+ unsigned long mask;
+
+ if (action == CPU_OFFLINE) {
+ /* Make sure that kswapd never becomes unschedulable. */
+ for_each_pgdat(pgdat) {
+ mask = node_to_cpumask(pgdat->node_id);
+ if (any_online_cpu(mask) < 0) {
+ mask = ~0UL;
+ set_cpus_allowed(pgdat->kswapd, mask);
+ }
+ }
+ }
+
+ if (action == CPU_ONLINE) {
+ for_each_pgdat(pgdat) {
+ mask = node_to_cpumask(pgdat->node_id);
+ mask &= ~(1UL << hotcpu);
+ if (any_online_cpu(mask) < 0) {
+ mask |= (1UL << hotcpu);
+ /* One of our CPUs came back: restore mask */
+ set_cpus_allowed(pgdat->kswapd, mask);
+ }
+ }
+ }
+#endif
+ return NOTIFY_OK;
+}
+
+static struct notifier_block cpu_nfb = { &cpu_callback, NULL, 0 };
+
static int __init kswapd_init(void)
{
pg_data_t *pgdat;
@@ -1003,6 +1046,7 @@
for_each_pgdat(pgdat)
kernel_thread(kswapd, pgdat, CLONE_KERNEL);
total_memory = nr_free_pagecache_pages();
+ register_cpu_notifier(&cpu_nfb);
return 0;
}

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