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-rw-r--r--arch/x86/include/asm/uv/uv_bau.h4
-rw-r--r--arch/x86/kernel/tlb_uv.c76
2 files changed, 77 insertions, 3 deletions
diff --git a/arch/x86/include/asm/uv/uv_bau.h b/arch/x86/include/asm/uv/uv_bau.h
index e5543c1a80ca..9b3e750ef2d8 100644
--- a/arch/x86/include/asm/uv/uv_bau.h
+++ b/arch/x86/include/asm/uv/uv_bau.h
@@ -34,6 +34,7 @@
*/
#define UV_ITEMS_PER_DESCRIPTOR 8
+/* the 'throttle' to prevent the hardware stay-busy bug */
#define MAX_BAU_CONCURRENT 3
#define UV_CPUS_PER_ACT_STATUS 32
#define UV_ACT_STATUS_MASK 0x3
@@ -338,6 +339,7 @@ struct bau_control {
int timeout_tries;
int ipi_attempts;
int conseccompletes;
+ int baudisabled;
int set_bau_off;
short cpu;
short uvhub_cpu;
@@ -389,6 +391,8 @@ struct ptc_stats {
unsigned long s_busy; /* status stayed busy past s/w timer */
unsigned long s_throttles; /* waits in throttle */
unsigned long s_retry_messages; /* retry broadcasts */
+ unsigned long s_bau_reenabled; /* for bau enable/disable */
+ unsigned long s_bau_disabled; /* for bau enable/disable */
/* destination statistics */
unsigned long d_alltlb; /* times all tlb's on this cpu were flushed */
unsigned long d_onetlb; /* times just one tlb on this cpu was flushed */
diff --git a/arch/x86/kernel/tlb_uv.c b/arch/x86/kernel/tlb_uv.c
index c8661779c51e..dc6a68312758 100644
--- a/arch/x86/kernel/tlb_uv.c
+++ b/arch/x86/kernel/tlb_uv.c
@@ -44,6 +44,9 @@ static int timeout_base_ns[] = {
};
static int timeout_us;
static int nobau;
+static int baudisabled;
+static spinlock_t disable_lock;
+static cycles_t congested_cycles;
/* tunables: */
static int max_bau_concurrent = MAX_BAU_CONCURRENT;
@@ -519,6 +522,35 @@ static inline int atomic_inc_unless_ge(spinlock_t *lock, atomic_t *v, int u)
return 1;
}
+/*
+ * Completions are taking a very long time due to a congested numalink
+ * network.
+ */
+static void
+disable_for_congestion(struct bau_control *bcp, struct ptc_stats *stat)
+{
+ int tcpu;
+ struct bau_control *tbcp;
+
+ /* let only one cpu do this disabling */
+ spin_lock(&disable_lock);
+ if (!baudisabled && bcp->period_requests &&
+ ((bcp->period_time / bcp->period_requests) > congested_cycles)) {
+ /* it becomes this cpu's job to turn on the use of the
+ BAU again */
+ baudisabled = 1;
+ bcp->set_bau_off = 1;
+ bcp->set_bau_on_time = get_cycles() +
+ sec_2_cycles(bcp->congested_period);
+ stat->s_bau_disabled++;
+ for_each_present_cpu(tcpu) {
+ tbcp = &per_cpu(bau_control, tcpu);
+ tbcp->baudisabled = 1;
+ }
+ }
+ spin_unlock(&disable_lock);
+}
+
/**
* uv_flush_send_and_wait
*
@@ -681,6 +713,14 @@ const struct cpumask *uv_flush_send_and_wait(struct bau_desc *bau_desc,
if (time2 > time1) {
elapsed = time2 - time1;
stat->s_time += elapsed;
+ if ((completion_status == FLUSH_COMPLETE) && (try == 1)) {
+ bcp->period_requests++;
+ bcp->period_time += elapsed;
+ if ((elapsed > congested_cycles) &&
+ (bcp->period_requests > bcp->congested_reps)) {
+ disable_for_congestion(bcp, stat);
+ }
+ }
} else
stat->s_requestor--; /* don't count this one */
if (completion_status == FLUSH_COMPLETE && try > 1)
@@ -747,12 +787,32 @@ const struct cpumask *uv_flush_tlb_others(const struct cpumask *cpumask,
struct cpumask *flush_mask;
struct ptc_stats *stat;
struct bau_control *bcp;
+ struct bau_control *tbcp;
/* kernel was booted 'nobau' */
if (nobau)
return cpumask;
bcp = &per_cpu(bau_control, cpu);
+ stat = &per_cpu(ptcstats, cpu);
+
+ /* bau was disabled due to slow response */
+ if (bcp->baudisabled) {
+ /* the cpu that disabled it must re-enable it */
+ if (bcp->set_bau_off) {
+ if (get_cycles() >= bcp->set_bau_on_time) {
+ stat->s_bau_reenabled++;
+ baudisabled = 0;
+ for_each_present_cpu(tcpu) {
+ tbcp = &per_cpu(bau_control, tcpu);
+ tbcp->baudisabled = 0;
+ tbcp->period_requests = 0;
+ tbcp->period_time = 0;
+ }
+ }
+ }
+ return cpumask;
+ }
/*
* Each sending cpu has a per-cpu mask which it fills from the caller's
@@ -793,7 +853,6 @@ const struct cpumask *uv_flush_tlb_others(const struct cpumask *cpumask,
else
return NULL;
}
- stat = &per_cpu(ptcstats, cpu);
stat->s_requestor++;
stat->s_ntargcpu += remotes;
remotes = bau_uvhub_weight(&bau_desc->distribution);
@@ -973,7 +1032,9 @@ static int uv_ptc_seq_show(struct seq_file *file, void *data)
seq_printf(file,
"sw_ack recv rtime all ");
seq_printf(file,
- "one mult none retry canc nocan reset rcan\n");
+ "one mult none retry canc nocan reset rcan ");
+ seq_printf(file,
+ "disable enable\n");
}
if (cpu < num_possible_cpus() && cpu_online(cpu)) {
stat = &per_cpu(ptcstats, cpu);
@@ -993,7 +1054,7 @@ static int uv_ptc_seq_show(struct seq_file *file, void *data)
/* destination side statistics */
seq_printf(file,
- "%lx %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld\n",
+ "%lx %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld ",
uv_read_global_mmr64(uv_cpu_to_pnode(cpu),
UVH_LB_BAU_INTD_SOFTWARE_ACKNOWLEDGE),
stat->d_requestee, cycles_2_us(stat->d_time),
@@ -1001,6 +1062,8 @@ static int uv_ptc_seq_show(struct seq_file *file, void *data)
stat->d_nomsg, stat->d_retries, stat->d_canceled,
stat->d_nocanceled, stat->d_resets,
stat->d_rcanceled);
+ seq_printf(file, "%ld %ld\n",
+ stat->s_bau_disabled, stat->s_bau_reenabled);
}
return 0;
@@ -1112,6 +1175,10 @@ static ssize_t uv_ptc_proc_write(struct file *file, const char __user *user,
"reset: number of ipi-style reset requests processed\n");
printk(KERN_DEBUG
"rcan: number messages canceled by reset requests\n");
+ printk(KERN_DEBUG
+ "disable: number times use of the BAU was disabled\n");
+ printk(KERN_DEBUG
+ "enable: number times use of the BAU was re-enabled\n");
} else if (input_arg == -1) {
for_each_present_cpu(cpu) {
stat = &per_cpu(ptcstats, cpu);
@@ -1568,6 +1635,7 @@ static void uv_init_per_cpu(int nuvhubs)
kfree(uvhub_descs);
for_each_present_cpu(cpu) {
bcp = &per_cpu(bau_control, cpu);
+ bcp->baudisabled = 0;
/* time interval to catch a hardware stay-busy bug */
bcp->timeout_interval = microsec_2_cycles(2*timeout_us);
bcp->max_bau_concurrent = max_bau_concurrent;
@@ -1609,6 +1677,8 @@ static int __init uv_bau_init(void)
uv_nshift = uv_hub_info->m_val;
uv_mmask = (1UL << uv_hub_info->m_val) - 1;
nuvhubs = uv_num_possible_blades();
+ spin_lock_init(&disable_lock);
+ congested_cycles = microsec_2_cycles(congested_response_us);
uv_init_per_cpu(nuvhubs);
generated by cgit v1.2.3 (git 2.25.1) at 2025-01-06 17:19:50 +0000