1 files changed, 177 insertions, 7 deletions

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index d1a40218e17e..931410d31a96 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -60,6 +60,21 @@
 
 #define GHES_ESTATUS_POOL_MIN_ALLOC_ORDER 3
 
+/* This is just an estimation for memory pool allocation */
+#define GHES_ESTATUS_CACHE_AVG_SIZE     512
+
+#define GHES_ESTATUS_CACHES_SIZE        4
+
+#define GHES_ESTATUS_IN_CACHE_MAX_NSEC  (10 * NSEC_PER_SEC)
+/* Prevent too many caches are allocated because of RCU */
+#define GHES_ESTATUS_CACHE_ALLOCED_MAX  (GHES_ESTATUS_CACHES_SIZE * 3 / 2)
+
+#define GHES_ESTATUS_CACHE_LEN(estatus_len)                     \
+        (sizeof(struct ghes_estatus_cache) + (estatus_len))
+#define GHES_ESTATUS_FROM_CACHE(estatus_cache)                  \
+        ((struct acpi_hest_generic_status *)                    \
+         ((struct ghes_estatus_cache *)(estatus_cache) + 1))
+
 #define GHES_ESTATUS_NODE_LEN(estatus_len)                      \
         (sizeof(struct ghes_estatus_node) + (estatus_len))
 #define GHES_ESTATUS_FROM_NODE(estatus_node)                            \
@@ -94,6 +109,14 @@ struct ghes_estatus_node {
         struct acpi_hest_generic *generic;
 };
 
+struct ghes_estatus_cache {
+        u32 estatus_len;
+        atomic_t count;
+        struct acpi_hest_generic *generic;
+        unsigned long long time_in;
+        struct rcu_head rcu;
+};
+
 int ghes_disable;
 module_param_named(disable, ghes_disable, bool, 0);
 
@@ -154,6 +177,9 @@ static unsigned long ghes_estatus_pool_size_request;
 static struct llist_head ghes_estatus_llist;
 static struct irq_work ghes_proc_irq_work;
 
+struct ghes_estatus_cache *ghes_estatus_caches[GHES_ESTATUS_CACHES_SIZE];
+static atomic_t ghes_estatus_cache_alloced;
+
 static int ghes_ioremap_init(void)
 {
         ghes_ioremap_area = __get_vm_area(PAGE_SIZE * GHES_IOREMAP_PAGES,
@@ -458,9 +484,9 @@ static void __ghes_print_estatus(const char *pfx,
         apei_estatus_print(pfx, estatus);
 }
 
-static void ghes_print_estatus(const char *pfx,
-                               const struct acpi_hest_generic *generic,
-                               const struct acpi_hest_generic_status *estatus)
+static int ghes_print_estatus(const char *pfx,
+                              const struct acpi_hest_generic *generic,
+                              const struct acpi_hest_generic_status *estatus)
 {
         /* Not more than 2 messages every 5 seconds */
         static DEFINE_RATELIMIT_STATE(ratelimit_corrected, 5*HZ, 2);
@@ -471,8 +497,137 @@ static void ghes_print_estatus(const char *pfx,
                 ratelimit = &ratelimit_corrected;
         else
                 ratelimit = &ratelimit_uncorrected;
-        if (__ratelimit(ratelimit))
+        if (__ratelimit(ratelimit)) {
                 __ghes_print_estatus(pfx, generic, estatus);
+                return 1;
+        }
+        return 0;
+}
+
+/*
+ * GHES error status reporting throttle, to report more kinds of
+ * errors, instead of just most frequently occurred errors.
+ */
+static int ghes_estatus_cached(struct acpi_hest_generic_status *estatus)
+{
+        u32 len;
+        int i, cached = 0;
+        unsigned long long now;
+        struct ghes_estatus_cache *cache;
+        struct acpi_hest_generic_status *cache_estatus;
+
+        len = apei_estatus_len(estatus);
+        rcu_read_lock();
+        for (i = 0; i < GHES_ESTATUS_CACHES_SIZE; i++) {
+                cache = rcu_dereference(ghes_estatus_caches[i]);
+                if (cache == NULL)
+                        continue;
+                if (len != cache->estatus_len)
+                        continue;
+                cache_estatus = GHES_ESTATUS_FROM_CACHE(cache);
+                if (memcmp(estatus, cache_estatus, len))
+                        continue;
+                atomic_inc(&cache->count);
+                now = sched_clock();
+                if (now - cache->time_in < GHES_ESTATUS_IN_CACHE_MAX_NSEC)
+                        cached = 1;
+                break;
+        }
+        rcu_read_unlock();
+        return cached;
+}
+
+static struct ghes_estatus_cache *ghes_estatus_cache_alloc(
+        struct acpi_hest_generic *generic,
+        struct acpi_hest_generic_status *estatus)
+{
+        int alloced;
+        u32 len, cache_len;
+        struct ghes_estatus_cache *cache;
+        struct acpi_hest_generic_status *cache_estatus;
+
+        alloced = atomic_add_return(1, &ghes_estatus_cache_alloced);
+        if (alloced > GHES_ESTATUS_CACHE_ALLOCED_MAX) {
+                atomic_dec(&ghes_estatus_cache_alloced);
+                return NULL;
+        }
+        len = apei_estatus_len(estatus);
+        cache_len = GHES_ESTATUS_CACHE_LEN(len);
+        cache = (void *)gen_pool_alloc(ghes_estatus_pool, cache_len);
+        if (!cache) {
+                atomic_dec(&ghes_estatus_cache_alloced);
+                return NULL;
+        }
+        cache_estatus = GHES_ESTATUS_FROM_CACHE(cache);
+        memcpy(cache_estatus, estatus, len);
+        cache->estatus_len = len;
+        atomic_set(&cache->count, 0);
+        cache->generic = generic;
+        cache->time_in = sched_clock();
+        return cache;
+}
+
+static void ghes_estatus_cache_free(struct ghes_estatus_cache *cache)
+{
+        u32 len;
+
+        len = apei_estatus_len(GHES_ESTATUS_FROM_CACHE(cache));
+        len = GHES_ESTATUS_CACHE_LEN(len);
+        gen_pool_free(ghes_estatus_pool, (unsigned long)cache, len);
+        atomic_dec(&ghes_estatus_cache_alloced);
+}
+
+static void ghes_estatus_cache_rcu_free(struct rcu_head *head)
+{
+        struct ghes_estatus_cache *cache;
+
+        cache = container_of(head, struct ghes_estatus_cache, rcu);
+        ghes_estatus_cache_free(cache);
+}
+
+static void ghes_estatus_cache_add(
+        struct acpi_hest_generic *generic,
+        struct acpi_hest_generic_status *estatus)
+{
+        int i, slot = -1, count;
+        unsigned long long now, duration, period, max_period = 0;
+        struct ghes_estatus_cache *cache, *slot_cache = NULL, *new_cache;
+
+        new_cache = ghes_estatus_cache_alloc(generic, estatus);
+        if (new_cache == NULL)
+                return;
+        rcu_read_lock();
+        now = sched_clock();
+        for (i = 0; i < GHES_ESTATUS_CACHES_SIZE; i++) {
+                cache = rcu_dereference(ghes_estatus_caches[i]);
+                if (cache == NULL) {
+                        slot = i;
+                        slot_cache = NULL;
+                        break;
+                }
+                duration = now - cache->time_in;
+                if (duration >= GHES_ESTATUS_IN_CACHE_MAX_NSEC) {
+                        slot = i;
+                        slot_cache = cache;
+                        break;
+                }
+                count = atomic_read(&cache->count);
+                period = duration / (count + 1);
+                if (period > max_period) {
+                        max_period = period;
+                        slot = i;
+                        slot_cache = cache;
+                }
+        }
+        /* new_cache must be put into array after its contents are written */
+        smp_wmb();
+        if (slot != -1 && cmpxchg(ghes_estatus_caches + slot,
+                                  slot_cache, new_cache) == slot_cache) {
+                if (slot_cache)
+                        call_rcu(&slot_cache->rcu, ghes_estatus_cache_rcu_free);
+        } else
+                ghes_estatus_cache_free(new_cache);
+        rcu_read_unlock();
 }
 
 static int ghes_proc(struct ghes *ghes)
@@ -482,9 +637,11 @@ static int ghes_proc(struct ghes *ghes)
         rc = ghes_read_estatus(ghes, 0);
         if (rc)
                 goto out;
-        ghes_print_estatus(NULL, ghes->generic, ghes->estatus);
+        if (!ghes_estatus_cached(ghes->estatus)) {
+                if (ghes_print_estatus(NULL, ghes->generic, ghes->estatus))
+                        ghes_estatus_cache_add(ghes->generic, ghes->estatus);
+        }
         ghes_do_proc(ghes->estatus);
-
 out:
         ghes_clear_estatus(ghes);
         return 0;
@@ -546,6 +703,7 @@ static void ghes_proc_in_irq(struct irq_work *irq_work)
 {
         struct llist_node *llnode, *next, *tail = NULL;
         struct ghes_estatus_node *estatus_node;
+        struct acpi_hest_generic *generic;
         struct acpi_hest_generic_status *estatus;
         u32 len, node_len;
 
@@ -569,7 +727,11 @@ static void ghes_proc_in_irq(struct irq_work *irq_work)
                 len = apei_estatus_len(estatus);
                 node_len = GHES_ESTATUS_NODE_LEN(len);
                 ghes_do_proc(estatus);
-                ghes_print_estatus(NULL, estatus_node->generic, estatus);
+                if (!ghes_estatus_cached(estatus)) {
+                        generic = estatus_node->generic;
+                        if (ghes_print_estatus(NULL, generic, estatus))
+                                ghes_estatus_cache_add(generic, estatus);
+                }
                 gen_pool_free(ghes_estatus_pool, (unsigned long)estatus_node,
                               node_len);
                 llnode = next;
@@ -622,6 +784,8 @@ static int ghes_notify_nmi(struct notifier_block *this,
                 if (!(ghes->flags & GHES_TO_CLEAR))
                         continue;
 #ifdef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
+                if (ghes_estatus_cached(ghes->estatus))
+                        goto next;
                 /* Save estatus for further processing in IRQ context */
                 len = apei_estatus_len(ghes->estatus);
                 node_len = GHES_ESTATUS_NODE_LEN(len);
@@ -633,6 +797,7 @@ static int ghes_notify_nmi(struct notifier_block *this,
                         memcpy(estatus, ghes->estatus, len);
                         llist_add(&estatus_node->llnode, &ghes_estatus_llist);
                 }
+next:
 #endif
                 ghes_clear_estatus(ghes);
         }
@@ -847,6 +1012,11 @@ static int __init ghes_init(void)
         if (rc)
                 goto err_ioremap_exit;
 
+        rc = ghes_estatus_pool_expand(GHES_ESTATUS_CACHE_AVG_SIZE *
+                                      GHES_ESTATUS_CACHE_ALLOCED_MAX);
+        if (rc)
+                goto err_pool_exit;
+
         rc = platform_driver_register(&ghes_platform_driver);
         if (rc)
                 goto err_pool_exit;