Avoid calling smp_processor_id in spl_magazine_age

The spl_magazine_age function had the implied assumption that it will
remain on its current cpu through its execution. In order to support
preempt enabled kernels, this assumption had to be removed.

The spl_kmem_magazine structure now holds the cpu id of the cpu it is
local to. This allows spl_magazine_age to use this field when scheduling
work to be done by the magazine's local cpu.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #98

diff --git a/include/sys/kmem.h b/include/sys/kmem.h
index 4383efb7c917d5f4106d99d31edc22593b14d459..344e2716b1588227093e84f431858dad3704016c 100644 (file)
--- a/include/sys/kmem.h
+++ b/include/sys/kmem.h
@@ -353,6 +353,7 @@ typedef struct spl_kmem_magazine {
        struct spl_kmem_cache   *skm_cache;     /* Owned by cache */
        struct delayed_work     skm_work;       /* Magazine reclaim work */
        unsigned long           skm_age;        /* Last cache access */
+       unsigned int            skm_cpu;        /* Owned by cpu */
        void                    *skm_objs[0];   /* Object pointers */
 } spl_kmem_magazine_t;
 

diff --git a/module/spl/spl-kmem.c b/module/spl/spl-kmem.c
index 28afc602450491a310a52da7ff6ead9811fa9f42..258d61478cc725e219b75734b86bce8304cf5a2f 100644 (file)
--- a/module/spl/spl-kmem.c
+++ b/module/spl/spl-kmem.c
@@ -1156,18 +1156,17 @@ spl_magazine_age(void *data)
        spl_kmem_magazine_t *skm =
                spl_get_work_data(data, spl_kmem_magazine_t, skm_work.work);
        spl_kmem_cache_t *skc = skm->skm_cache;
-       int i = smp_processor_id();
 
        ASSERT(skm->skm_magic == SKM_MAGIC);
        ASSERT(skc->skc_magic == SKC_MAGIC);
-       ASSERT(skc->skc_mag[i] == skm);
+       ASSERT(skc->skc_mag[skm->skm_cpu] == skm);
 
        if (skm->skm_avail > 0 &&
            time_after(jiffies, skm->skm_age + skc->skc_delay * HZ))
                (void)spl_cache_flush(skc, skm, skm->skm_refill);
 
        if (!test_bit(KMC_BIT_DESTROY, &skc->skc_flags))
-               schedule_delayed_work_on(i, &skm->skm_work,
+               schedule_delayed_work_on(skm->skm_cpu, &skm->skm_work,
                                         skc->skc_delay / 3 * HZ);
 }
 
@@ -1267,14 +1266,14 @@ spl_magazine_size(spl_kmem_cache_t *skc)
  * Allocate a per-cpu magazine to associate with a specific core.
  */
 static spl_kmem_magazine_t *
-spl_magazine_alloc(spl_kmem_cache_t *skc, int node)
+spl_magazine_alloc(spl_kmem_cache_t *skc, int cpu)
 {
        spl_kmem_magazine_t *skm;
        int size = sizeof(spl_kmem_magazine_t) +
                   sizeof(void *) * skc->skc_mag_size;
        SENTRY;
 
-       skm = kmem_alloc_node(size, KM_SLEEP, node);
+       skm = kmem_alloc_node(size, KM_SLEEP, cpu_to_node(cpu));
        if (skm) {
                skm->skm_magic = SKM_MAGIC;
                skm->skm_avail = 0;
@@ -1283,6 +1282,7 @@ spl_magazine_alloc(spl_kmem_cache_t *skc, int node)
                skm->skm_cache = skc;
                spl_init_delayed_work(&skm->skm_work, spl_magazine_age, skm);
                skm->skm_age = jiffies;
+               skm->skm_cpu = cpu;
        }
 
        SRETURN(skm);
@@ -1318,7 +1318,7 @@ spl_magazine_create(spl_kmem_cache_t *skc)
        skc->skc_mag_refill = (skc->skc_mag_size + 1) / 2;
 
        for_each_online_cpu(i) {
-               skc->skc_mag[i] = spl_magazine_alloc(skc, cpu_to_node(i));
+               skc->skc_mag[i] = spl_magazine_alloc(skc, i);
                if (!skc->skc_mag[i]) {
                        for (i--; i >= 0; i--)
                                spl_magazine_free(skc->skc_mag[i]);