]> git.kernelconcepts.de Git - karo-tx-linux.git/blobdiff - arch/x86/kernel/tlb_uv.c
x86, UV: Make kdump avoid stack dumps
[karo-tx-linux.git] / arch / x86 / kernel / tlb_uv.c
index 7fea555929e24f2f411ea019b426e64c05ac2df0..59efb5390b37bec6d0de735c93483c35ba0ca43a 100644 (file)
@@ -8,6 +8,7 @@
  */
 #include <linux/seq_file.h>
 #include <linux/proc_fs.h>
+#include <linux/debugfs.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
 
 #include <asm/irq_vectors.h>
 #include <asm/timer.h>
 
-struct msg_desc {
-       struct bau_payload_queue_entry *msg;
-       int msg_slot;
-       int sw_ack_slot;
-       struct bau_payload_queue_entry *va_queue_first;
-       struct bau_payload_queue_entry *va_queue_last;
+/* timeouts in nanoseconds (indexed by UVH_AGING_PRESCALE_SEL urgency7 30:28) */
+static int timeout_base_ns[] = {
+               20,
+               160,
+               1280,
+               10240,
+               81920,
+               655360,
+               5242880,
+               167772160
 };
-
-#define UV_INTD_SOFT_ACK_TIMEOUT_PERIOD        0x000000000bUL
-
-static int uv_bau_max_concurrent __read_mostly;
-
+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;
+static int max_bau_concurrent_constant = MAX_BAU_CONCURRENT;
+static int plugged_delay = PLUGGED_DELAY;
+static int plugsb4reset = PLUGSB4RESET;
+static int timeoutsb4reset = TIMEOUTSB4RESET;
+static int ipi_reset_limit = IPI_RESET_LIMIT;
+static int complete_threshold = COMPLETE_THRESHOLD;
+static int congested_response_us = CONGESTED_RESPONSE_US;
+static int congested_reps = CONGESTED_REPS;
+static int congested_period = CONGESTED_PERIOD;
+static struct dentry *tunables_dir;
+static struct dentry *tunables_file;
+
 static int __init setup_nobau(char *arg)
 {
        nobau = 1;
@@ -52,10 +71,6 @@ static DEFINE_PER_CPU(struct ptc_stats, ptcstats);
 static DEFINE_PER_CPU(struct bau_control, bau_control);
 static DEFINE_PER_CPU(cpumask_var_t, uv_flush_tlb_mask);
 
-struct reset_args {
-       int sender;
-};
-
 /*
  * Determine the first node on a uvhub. 'Nodes' are used for kernel
  * memory allocation.
@@ -126,7 +141,7 @@ static inline void uv_bau_process_retry_msg(struct msg_desc *mdp,
        struct ptc_stats *stat;
 
        msg = mdp->msg;
-       stat = &per_cpu(ptcstats, bcp->cpu);
+       stat = bcp->statp;
        stat->d_retries++;
        /*
         * cancel any message from msg+1 to the retry itself
@@ -146,15 +161,14 @@ static inline void uv_bau_process_retry_msg(struct msg_desc *mdp,
                        slot2 = msg2 - mdp->va_queue_first;
                        mmr = uv_read_local_mmr
                                (UVH_LB_BAU_INTD_SOFTWARE_ACKNOWLEDGE);
-                       msg_res = ((msg2->sw_ack_vector << 8) |
-                                  msg2->sw_ack_vector);
+                       msg_res = msg2->sw_ack_vector;
                        /*
                         * This is a message retry; clear the resources held
                         * by the previous message only if they timed out.
                         * If it has not timed out we have an unexpected
                         * situation to report.
                         */
-                       if (mmr & (msg_res << 8)) {
+                       if (mmr & (msg_res << UV_SW_ACK_NPENDING)) {
                                /*
                                 * is the resource timed out?
                                 * make everyone ignore the cancelled message.
@@ -164,9 +178,9 @@ static inline void uv_bau_process_retry_msg(struct msg_desc *mdp,
                                cancel_count++;
                                uv_write_local_mmr(
                                    UVH_LB_BAU_INTD_SOFTWARE_ACKNOWLEDGE_ALIAS,
-                                       (msg_res << 8) | msg_res);
-                       } else
-                               printk(KERN_INFO "note bau retry: no effect\n");
+                                       (msg_res << UV_SW_ACK_NPENDING) |
+                                        msg_res);
+                       }
                }
        }
        if (!cancel_count)
@@ -190,7 +204,7 @@ static void uv_bau_process_message(struct msg_desc *mdp,
         * This must be a normal message, or retry of a normal message
         */
        msg = mdp->msg;
-       stat = &per_cpu(ptcstats, bcp->cpu);
+       stat = bcp->statp;
        if (msg->address == TLB_FLUSH_ALL) {
                local_flush_tlb();
                stat->d_alltlb++;
@@ -274,7 +288,7 @@ uv_do_reset(void *ptr)
 
        bcp = &per_cpu(bau_control, smp_processor_id());
        rap = (struct reset_args *)ptr;
-       stat = &per_cpu(ptcstats, bcp->cpu);
+       stat = bcp->statp;
        stat->d_resets++;
 
        /*
@@ -302,13 +316,13 @@ uv_do_reset(void *ptr)
                         */
                        mmr = uv_read_local_mmr
                                        (UVH_LB_BAU_INTD_SOFTWARE_ACKNOWLEDGE);
-                       msg_res = ((msg->sw_ack_vector << 8) |
-                                                  msg->sw_ack_vector);
+                       msg_res = msg->sw_ack_vector;
                        if (mmr & msg_res) {
                                stat->d_rcanceled++;
                                uv_write_local_mmr(
                                    UVH_LB_BAU_INTD_SOFTWARE_ACKNOWLEDGE_ALIAS,
-                                                       msg_res);
+                                       (msg_res << UV_SW_ACK_NPENDING) |
+                                        msg_res);
                        }
                }
        }
@@ -386,17 +400,12 @@ static int uv_wait_completion(struct bau_desc *bau_desc,
        unsigned long mmr_offset, int right_shift, int this_cpu,
        struct bau_control *bcp, struct bau_control *smaster, long try)
 {
-       int relaxes = 0;
        unsigned long descriptor_status;
-       unsigned long mmr;
-       unsigned long mask;
        cycles_t ttime;
-       cycles_t timeout_time;
-       struct ptc_stats *stat = &per_cpu(ptcstats, this_cpu);
+       struct ptc_stats *stat = bcp->statp;
        struct bau_control *hmaster;
 
        hmaster = bcp->uvhub_master;
-       timeout_time = get_cycles() + bcp->timeout_interval;
 
        /* spin on the status MMR, waiting for it to go idle */
        while ((descriptor_status = (((unsigned long)
@@ -423,7 +432,8 @@ static int uv_wait_completion(struct bau_desc *bau_desc,
                         * pending.  In that case hardware returns the
                         * ERROR that looks like a destination timeout.
                         */
-                       if (cycles_2_us(ttime - bcp->send_message) < BIOS_TO) {
+                       if (cycles_2_us(ttime - bcp->send_message) <
+                                                       timeout_us) {
                                bcp->conseccompletes = 0;
                                return FLUSH_RETRY_PLUGGED;
                        }
@@ -435,26 +445,6 @@ static int uv_wait_completion(struct bau_desc *bau_desc,
                         * descriptor_status is still BUSY
                         */
                        cpu_relax();
-                       relaxes++;
-                       if (relaxes >= 10000) {
-                               relaxes = 0;
-                               if (get_cycles() > timeout_time) {
-                                       quiesce_local_uvhub(hmaster);
-
-                                       /* single-thread the register change */
-                                       spin_lock(&hmaster->masks_lock);
-                                       mmr = uv_read_local_mmr(mmr_offset);
-                                       mask = 0UL;
-                                       mask |= (3UL < right_shift);
-                                       mask = ~mask;
-                                       mmr &= mask;
-                                       uv_write_local_mmr(mmr_offset, mmr);
-                                       spin_unlock(&hmaster->masks_lock);
-                                       end_uvhub_quiesce(hmaster);
-                                       stat->s_busy++;
-                                       return FLUSH_GIVEUP;
-                               }
-                       }
                }
        }
        bcp->conseccompletes++;
@@ -494,56 +484,116 @@ static inline int atomic_inc_unless_ge(spinlock_t *lock, atomic_t *v, int u)
        return 1;
 }
 
+/*
+ * Our retries are blocked by all destination swack resources being
+ * in use, and a timeout is pending. In that case hardware immediately
+ * returns the ERROR that looks like a destination timeout.
+ */
+static void
+destination_plugged(struct bau_desc *bau_desc, struct bau_control *bcp,
+                       struct bau_control *hmaster, struct ptc_stats *stat)
+{
+       udelay(bcp->plugged_delay);
+       bcp->plugged_tries++;
+       if (bcp->plugged_tries >= bcp->plugsb4reset) {
+               bcp->plugged_tries = 0;
+               quiesce_local_uvhub(hmaster);
+               spin_lock(&hmaster->queue_lock);
+               uv_reset_with_ipi(&bau_desc->distribution, bcp->cpu);
+               spin_unlock(&hmaster->queue_lock);
+               end_uvhub_quiesce(hmaster);
+               bcp->ipi_attempts++;
+               stat->s_resets_plug++;
+       }
+}
+
+static void
+destination_timeout(struct bau_desc *bau_desc, struct bau_control *bcp,
+                       struct bau_control *hmaster, struct ptc_stats *stat)
+{
+       hmaster->max_bau_concurrent = 1;
+       bcp->timeout_tries++;
+       if (bcp->timeout_tries >= bcp->timeoutsb4reset) {
+               bcp->timeout_tries = 0;
+               quiesce_local_uvhub(hmaster);
+               spin_lock(&hmaster->queue_lock);
+               uv_reset_with_ipi(&bau_desc->distribution, bcp->cpu);
+               spin_unlock(&hmaster->queue_lock);
+               end_uvhub_quiesce(hmaster);
+               bcp->ipi_attempts++;
+               stat->s_resets_timeout++;
+       }
+}
+
+/*
+ * 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
  *
  * Send a broadcast and wait for it to complete.
  *
- * The flush_mask contains the cpus the broadcast is to be sent to, plus
+ * The flush_mask contains the cpus the broadcast is to be sent to including
  * cpus that are on the local uvhub.
  *
- * Returns NULL if all flushing represented in the mask was done. The mask
- * is zeroed.
- * Returns @flush_mask if some remote flushing remains to be done. The
- * mask will have some bits still set, representing any cpus on the local
- * uvhub (not current cpu) and any on remote uvhubs if the broadcast failed.
+ * Returns 0 if all flushing represented in the mask was done.
+ * Returns 1 if it gives up entirely and the original cpu mask is to be
+ * returned to the kernel.
  */
-const struct cpumask *uv_flush_send_and_wait(struct bau_desc *bau_desc,
-                                            struct cpumask *flush_mask,
-                                            struct bau_control *bcp)
+int uv_flush_send_and_wait(struct bau_desc *bau_desc,
+                          struct cpumask *flush_mask, struct bau_control *bcp)
 {
        int right_shift;
-       int uvhub;
-       int bit;
        int completion_status = 0;
        int seq_number = 0;
        long try = 0;
        int cpu = bcp->uvhub_cpu;
        int this_cpu = bcp->cpu;
-       int this_uvhub = bcp->uvhub;
        unsigned long mmr_offset;
        unsigned long index;
        cycles_t time1;
        cycles_t time2;
-       struct ptc_stats *stat = &per_cpu(ptcstats, bcp->cpu);
+       cycles_t elapsed;
+       struct ptc_stats *stat = bcp->statp;
        struct bau_control *smaster = bcp->socket_master;
        struct bau_control *hmaster = bcp->uvhub_master;
 
-       /*
-        * Spin here while there are hmaster->max_concurrent or more active
-        * descriptors. This is the per-uvhub 'throttle'.
-        */
        if (!atomic_inc_unless_ge(&hmaster->uvhub_lock,
                        &hmaster->active_descriptor_count,
-                       hmaster->max_concurrent)) {
+                       hmaster->max_bau_concurrent)) {
                stat->s_throttles++;
                do {
                        cpu_relax();
                } while (!atomic_inc_unless_ge(&hmaster->uvhub_lock,
                        &hmaster->active_descriptor_count,
-                       hmaster->max_concurrent));
+                       hmaster->max_bau_concurrent));
        }
-
        while (hmaster->uvhub_quiesce)
                cpu_relax();
 
@@ -557,23 +607,10 @@ const struct cpumask *uv_flush_send_and_wait(struct bau_desc *bau_desc,
        }
        time1 = get_cycles();
        do {
-               /*
-                * Every message from any given cpu gets a unique message
-                * sequence number. But retries use that same number.
-                * Our message may have timed out at the destination because
-                * all sw-ack resources are in use and there is a timeout
-                * pending there.  In that case, our last send never got
-                * placed into the queue and we need to persist until it
-                * does.
-                *
-                * Make any retry a type MSG_RETRY so that the destination will
-                * free any resource held by a previous message from this cpu.
-                */
                if (try == 0) {
-                       /* use message type set by the caller the first time */
+                       bau_desc->header.msg_type = MSG_REGULAR;
                        seq_number = bcp->message_number++;
                } else {
-                       /* use RETRY type on all the rest; same sequence */
                        bau_desc->header.msg_type = MSG_RETRY;
                        stat->s_retry_messages++;
                }
@@ -581,50 +618,17 @@ const struct cpumask *uv_flush_send_and_wait(struct bau_desc *bau_desc,
                index = (1UL << UVH_LB_BAU_SB_ACTIVATION_CONTROL_PUSH_SHFT) |
                        bcp->uvhub_cpu;
                bcp->send_message = get_cycles();
-
                uv_write_local_mmr(UVH_LB_BAU_SB_ACTIVATION_CONTROL, index);
-
                try++;
                completion_status = uv_wait_completion(bau_desc, mmr_offset,
                        right_shift, this_cpu, bcp, smaster, try);
 
                if (completion_status == FLUSH_RETRY_PLUGGED) {
-                       /*
-                        * Our retries may be blocked by all destination swack
-                        * resources being consumed, and a timeout pending. In
-                        * that case hardware immediately returns the ERROR
-                        * that looks like a destination timeout.
-                        */
-                       udelay(TIMEOUT_DELAY);
-                       bcp->plugged_tries++;
-                       if (bcp->plugged_tries >= PLUGSB4RESET) {
-                               bcp->plugged_tries = 0;
-                               quiesce_local_uvhub(hmaster);
-                               spin_lock(&hmaster->queue_lock);
-                               uv_reset_with_ipi(&bau_desc->distribution,
-                                                       this_cpu);
-                               spin_unlock(&hmaster->queue_lock);
-                               end_uvhub_quiesce(hmaster);
-                               bcp->ipi_attempts++;
-                               stat->s_resets_plug++;
-                       }
+                       destination_plugged(bau_desc, bcp, hmaster, stat);
                } else if (completion_status == FLUSH_RETRY_TIMEOUT) {
-                       hmaster->max_concurrent = 1;
-                       bcp->timeout_tries++;
-                       udelay(TIMEOUT_DELAY);
-                       if (bcp->timeout_tries >= TIMEOUTSB4RESET) {
-                               bcp->timeout_tries = 0;
-                               quiesce_local_uvhub(hmaster);
-                               spin_lock(&hmaster->queue_lock);
-                               uv_reset_with_ipi(&bau_desc->distribution,
-                                                               this_cpu);
-                               spin_unlock(&hmaster->queue_lock);
-                               end_uvhub_quiesce(hmaster);
-                               bcp->ipi_attempts++;
-                               stat->s_resets_timeout++;
-                       }
+                       destination_timeout(bau_desc, bcp, hmaster, stat);
                }
-               if (bcp->ipi_attempts >= 3) {
+               if (bcp->ipi_attempts >= bcp->ipi_reset_limit) {
                        bcp->ipi_attempts = 0;
                        completion_status = FLUSH_GIVEUP;
                        break;
@@ -633,49 +637,36 @@ const struct cpumask *uv_flush_send_and_wait(struct bau_desc *bau_desc,
        } while ((completion_status == FLUSH_RETRY_PLUGGED) ||
                 (completion_status == FLUSH_RETRY_TIMEOUT));
        time2 = get_cycles();
-
-       if ((completion_status == FLUSH_COMPLETE) && (bcp->conseccompletes > 5)
-           && (hmaster->max_concurrent < hmaster->max_concurrent_constant))
-                       hmaster->max_concurrent++;
-
-       /*
-        * hold any cpu not timing out here; no other cpu currently held by
-        * the 'throttle' should enter the activation code
-        */
+       bcp->plugged_tries = 0;
+       bcp->timeout_tries = 0;
+       if ((completion_status == FLUSH_COMPLETE) &&
+           (bcp->conseccompletes > bcp->complete_threshold) &&
+           (hmaster->max_bau_concurrent <
+                                       hmaster->max_bau_concurrent_constant))
+                       hmaster->max_bau_concurrent++;
        while (hmaster->uvhub_quiesce)
                cpu_relax();
        atomic_dec(&hmaster->active_descriptor_count);
-
-       /* guard against cycles wrap */
-       if (time2 > time1)
-               stat->s_time += (time2 - time1);
-       else
-               stat->s_requestor--; /* don't count this one */
+       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--;
        if (completion_status == FLUSH_COMPLETE && try > 1)
                stat->s_retriesok++;
        else if (completion_status == FLUSH_GIVEUP) {
-               /*
-                * Cause the caller to do an IPI-style TLB shootdown on
-                * the target cpu's, all of which are still in the mask.
-                */
                stat->s_giveup++;
-               return flush_mask;
-       }
-
-       /*
-        * Success, so clear the remote cpu's from the mask so we don't
-        * use the IPI method of shootdown on them.
-        */
-       for_each_cpu(bit, flush_mask) {
-               uvhub = uv_cpu_to_blade_id(bit);
-               if (uvhub == this_uvhub)
-                       continue;
-               cpumask_clear_cpu(bit, flush_mask);
+               return 1;
        }
-       if (!cpumask_empty(flush_mask))
-               return flush_mask;
-
-       return NULL;
+       return 0;
 }
 
 /**
@@ -707,70 +698,89 @@ const struct cpumask *uv_flush_tlb_others(const struct cpumask *cpumask,
                                          struct mm_struct *mm,
                                          unsigned long va, unsigned int cpu)
 {
-       int remotes;
        int tcpu;
        int uvhub;
        int locals = 0;
+       int remotes = 0;
+       int hubs = 0;
        struct bau_desc *bau_desc;
        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 = bcp->statp;
+
+       /* 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
-        * cpu mask.  Only remote cpus are converted to uvhubs and copied.
+        * cpu mask.  All cpus are converted to uvhubs and copied to the
+        * activation descriptor.
         */
        flush_mask = (struct cpumask *)per_cpu(uv_flush_tlb_mask, cpu);
-       /*
-        * copy cpumask to flush_mask, removing current cpu
-        * (current cpu should already have been flushed by the caller and
-        *  should never be returned if we return flush_mask)
-        */
+       /* don't actually do a shootdown of the local cpu */
        cpumask_andnot(flush_mask, cpumask, cpumask_of(cpu));
        if (cpu_isset(cpu, *cpumask))
-               locals++;  /* current cpu was targeted */
+               stat->s_ntargself++;
 
        bau_desc = bcp->descriptor_base;
        bau_desc += UV_ITEMS_PER_DESCRIPTOR * bcp->uvhub_cpu;
-
        bau_uvhubs_clear(&bau_desc->distribution, UV_DISTRIBUTION_SIZE);
-       remotes = 0;
+
+       /* cpu statistics */
        for_each_cpu(tcpu, flush_mask) {
                uvhub = uv_cpu_to_blade_id(tcpu);
-               if (uvhub == bcp->uvhub) {
-                       locals++;
-                       continue;
-               }
                bau_uvhub_set(uvhub, &bau_desc->distribution);
-               remotes++;
-       }
-       if (remotes == 0) {
-               /*
-                * No off_hub flushing; return status for local hub.
-                * Return the caller's mask if all were local (the current
-                * cpu may be in that mask).
-                */
-               if (locals)
-                       return cpumask;
+               if (uvhub == bcp->uvhub)
+                       locals++;
                else
-                       return NULL;
+                       remotes++;
        }
-       stat = &per_cpu(ptcstats, cpu);
+       if ((locals + remotes) == 0)
+               return NULL;
        stat->s_requestor++;
-       stat->s_ntargcpu += remotes;
+       stat->s_ntargcpu += remotes + locals;
+       stat->s_ntargremotes += remotes;
+       stat->s_ntarglocals += locals;
        remotes = bau_uvhub_weight(&bau_desc->distribution);
-       stat->s_ntarguvhub += remotes;
-       if (remotes >= 16)
+
+       /* uvhub statistics */
+       hubs = bau_uvhub_weight(&bau_desc->distribution);
+       if (locals) {
+               stat->s_ntarglocaluvhub++;
+               stat->s_ntargremoteuvhub += (hubs - 1);
+       } else
+               stat->s_ntargremoteuvhub += hubs;
+       stat->s_ntarguvhub += hubs;
+       if (hubs >= 16)
                stat->s_ntarguvhub16++;
-       else if (remotes >= 8)
+       else if (hubs >= 8)
                stat->s_ntarguvhub8++;
-       else if (remotes >= 4)
+       else if (hubs >= 4)
                stat->s_ntarguvhub4++;
-       else if (remotes >= 2)
+       else if (hubs >= 2)
                stat->s_ntarguvhub2++;
        else
                stat->s_ntarguvhub1++;
@@ -779,10 +789,13 @@ const struct cpumask *uv_flush_tlb_others(const struct cpumask *cpumask,
        bau_desc->payload.sending_cpu = cpu;
 
        /*
-        * uv_flush_send_and_wait returns null if all cpu's were messaged, or
-        * the adjusted flush_mask if any cpu's were not messaged.
+        * uv_flush_send_and_wait returns 0 if all cpu's were messaged,
+        * or 1 if it gave up and the original cpumask should be returned.
         */
-       return uv_flush_send_and_wait(bau_desc, flush_mask, bcp);
+       if (!uv_flush_send_and_wait(bau_desc, flush_mask, bcp))
+               return NULL;
+       else
+               return cpumask;
 }
 
 /*
@@ -810,7 +823,7 @@ void uv_bau_message_interrupt(struct pt_regs *regs)
 
        time_start = get_cycles();
        bcp = &per_cpu(bau_control, smp_processor_id());
-       stat = &per_cpu(ptcstats, smp_processor_id());
+       stat = bcp->statp;
        msgdesc.va_queue_first = bcp->va_queue_first;
        msgdesc.va_queue_last = bcp->va_queue_last;
        msg = bcp->bau_msg_head;
@@ -908,12 +921,12 @@ static void uv_ptc_seq_stop(struct seq_file *file, void *data)
 }
 
 static inline unsigned long long
-millisec_2_cycles(unsigned long millisec)
+microsec_2_cycles(unsigned long microsec)
 {
        unsigned long ns;
        unsigned long long cyc;
 
-       ns = millisec * 1000;
+       ns = microsec * 1000;
        cyc = (ns << CYC2NS_SCALE_FACTOR)/(per_cpu(cyc2ns, smp_processor_id()));
        return cyc;
 }
@@ -931,15 +944,19 @@ static int uv_ptc_seq_show(struct seq_file *file, void *data)
 
        if (!cpu) {
                seq_printf(file,
-                       "# cpu sent stime numuvhubs numuvhubs16 numuvhubs8 ");
+                       "# cpu sent stime self locals remotes ncpus localhub ");
                seq_printf(file,
-                       "numuvhubs4 numuvhubs2 numuvhubs1 numcpus dto ");
+                       "remotehub numuvhubs numuvhubs16 numuvhubs8 ");
+               seq_printf(file,
+                       "numuvhubs4 numuvhubs2 numuvhubs1 dto ");
                seq_printf(file,
                        "retries rok resetp resett giveup sto bz throt ");
                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);
@@ -947,18 +964,23 @@ static int uv_ptc_seq_show(struct seq_file *file, void *data)
                seq_printf(file,
                        "cpu %d %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld ",
                           cpu, stat->s_requestor, cycles_2_us(stat->s_time),
-                          stat->s_ntarguvhub, stat->s_ntarguvhub16,
+                          stat->s_ntargself, stat->s_ntarglocals,
+                          stat->s_ntargremotes, stat->s_ntargcpu,
+                          stat->s_ntarglocaluvhub, stat->s_ntargremoteuvhub,
+                          stat->s_ntarguvhub, stat->s_ntarguvhub16);
+               seq_printf(file, "%ld %ld %ld %ld %ld ",
                           stat->s_ntarguvhub8, stat->s_ntarguvhub4,
                           stat->s_ntarguvhub2, stat->s_ntarguvhub1,
-                          stat->s_ntargcpu, stat->s_dtimeout);
+                          stat->s_dtimeout);
                seq_printf(file, "%ld %ld %ld %ld %ld %ld %ld %ld ",
                           stat->s_retry_messages, stat->s_retriesok,
                           stat->s_resets_plug, stat->s_resets_timeout,
                           stat->s_giveup, stat->s_stimeout,
                           stat->s_busy, stat->s_throttles);
+
                /* 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),
@@ -966,15 +988,36 @@ 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;
 }
 
+/*
+ * Display the tunables thru debugfs
+ */
+static ssize_t tunables_read(struct file *file, char __user *userbuf,
+                                               size_t count, loff_t *ppos)
+{
+       char buf[300];
+       int ret;
+
+       ret = snprintf(buf, 300, "%s %s %s\n%d %d %d %d %d %d %d %d %d\n",
+               "max_bau_concurrent plugged_delay plugsb4reset",
+               "timeoutsb4reset ipi_reset_limit complete_threshold",
+               "congested_response_us congested_reps congested_period",
+               max_bau_concurrent, plugged_delay, plugsb4reset,
+               timeoutsb4reset, ipi_reset_limit, complete_threshold,
+               congested_response_us, congested_reps, congested_period);
+
+       return simple_read_from_buffer(userbuf, count, ppos, buf, ret);
+}
+
 /*
  * -1: resetf the statistics
  *  0: display meaning of the statistics
- * >0: maximum concurrent active descriptors per uvhub (throttle)
  */
 static ssize_t uv_ptc_proc_write(struct file *file, const char __user *user,
                                 size_t count, loff_t *data)
@@ -983,7 +1026,6 @@ static ssize_t uv_ptc_proc_write(struct file *file, const char __user *user,
        long input_arg;
        char optstr[64];
        struct ptc_stats *stat;
-       struct bau_control *bcp;
 
        if (count == 0 || count > sizeof(optstr))
                return -EINVAL;
@@ -1059,29 +1101,158 @@ 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);
                        memset(stat, 0, sizeof(struct ptc_stats));
                }
-       } else {
-               uv_bau_max_concurrent = input_arg;
-               bcp = &per_cpu(bau_control, smp_processor_id());
-               if (uv_bau_max_concurrent < 1 ||
-                   uv_bau_max_concurrent > bcp->cpus_in_uvhub) {
-                       printk(KERN_DEBUG
-                               "Error: BAU max concurrent %d; %d is invalid\n",
-                               bcp->max_concurrent, uv_bau_max_concurrent);
-                       return -EINVAL;
-               }
-               printk(KERN_DEBUG "Set BAU max concurrent:%d\n",
-                      uv_bau_max_concurrent);
-               for_each_present_cpu(cpu) {
-                       bcp = &per_cpu(bau_control, cpu);
-                       bcp->max_concurrent = uv_bau_max_concurrent;
+       }
+
+       return count;
+}
+
+static int local_atoi(const char *name)
+{
+       int val = 0;
+
+       for (;; name++) {
+               switch (*name) {
+               case '0' ... '9':
+                       val = 10*val+(*name-'0');
+                       break;
+               default:
+                       return val;
                }
        }
+}
+
+/*
+ * set the tunables
+ * 0 values reset them to defaults
+ */
+static ssize_t tunables_write(struct file *file, const char __user *user,
+                                size_t count, loff_t *data)
+{
+       int cpu;
+       int cnt = 0;
+       int val;
+       char *p;
+       char *q;
+       char instr[64];
+       struct bau_control *bcp;
+
+       if (count == 0 || count > sizeof(instr)-1)
+               return -EINVAL;
+       if (copy_from_user(instr, user, count))
+               return -EFAULT;
+
+       instr[count] = '\0';
+       /* count the fields */
+       p = instr + strspn(instr, WHITESPACE);
+       q = p;
+       for (; *p; p = q + strspn(q, WHITESPACE)) {
+               q = p + strcspn(p, WHITESPACE);
+               cnt++;
+               if (q == p)
+                       break;
+       }
+       if (cnt != 9) {
+               printk(KERN_INFO "bau tunable error: should be 9 numbers\n");
+               return -EINVAL;
+       }
 
+       p = instr + strspn(instr, WHITESPACE);
+       q = p;
+       for (cnt = 0; *p; p = q + strspn(q, WHITESPACE), cnt++) {
+               q = p + strcspn(p, WHITESPACE);
+               val = local_atoi(p);
+               switch (cnt) {
+               case 0:
+                       if (val == 0) {
+                               max_bau_concurrent = MAX_BAU_CONCURRENT;
+                               max_bau_concurrent_constant =
+                                                       MAX_BAU_CONCURRENT;
+                               continue;
+                       }
+                       bcp = &per_cpu(bau_control, smp_processor_id());
+                       if (val < 1 || val > bcp->cpus_in_uvhub) {
+                               printk(KERN_DEBUG
+                               "Error: BAU max concurrent %d is invalid\n",
+                               val);
+                               return -EINVAL;
+                       }
+                       max_bau_concurrent = val;
+                       max_bau_concurrent_constant = val;
+                       continue;
+               case 1:
+                       if (val == 0)
+                               plugged_delay = PLUGGED_DELAY;
+                       else
+                               plugged_delay = val;
+                       continue;
+               case 2:
+                       if (val == 0)
+                               plugsb4reset = PLUGSB4RESET;
+                       else
+                               plugsb4reset = val;
+                       continue;
+               case 3:
+                       if (val == 0)
+                               timeoutsb4reset = TIMEOUTSB4RESET;
+                       else
+                               timeoutsb4reset = val;
+                       continue;
+               case 4:
+                       if (val == 0)
+                               ipi_reset_limit = IPI_RESET_LIMIT;
+                       else
+                               ipi_reset_limit = val;
+                       continue;
+               case 5:
+                       if (val == 0)
+                               complete_threshold = COMPLETE_THRESHOLD;
+                       else
+                               complete_threshold = val;
+                       continue;
+               case 6:
+                       if (val == 0)
+                               congested_response_us = CONGESTED_RESPONSE_US;
+                       else
+                               congested_response_us = val;
+                       continue;
+               case 7:
+                       if (val == 0)
+                               congested_reps = CONGESTED_REPS;
+                       else
+                               congested_reps = val;
+                       continue;
+               case 8:
+                       if (val == 0)
+                               congested_period = CONGESTED_PERIOD;
+                       else
+                               congested_period = val;
+                       continue;
+               }
+               if (q == p)
+                       break;
+       }
+       for_each_present_cpu(cpu) {
+               bcp = &per_cpu(bau_control, cpu);
+               bcp->max_bau_concurrent = max_bau_concurrent;
+               bcp->max_bau_concurrent_constant = max_bau_concurrent;
+               bcp->plugged_delay = plugged_delay;
+               bcp->plugsb4reset = plugsb4reset;
+               bcp->timeoutsb4reset = timeoutsb4reset;
+               bcp->ipi_reset_limit = ipi_reset_limit;
+               bcp->complete_threshold = complete_threshold;
+               bcp->congested_response_us = congested_response_us;
+               bcp->congested_reps = congested_reps;
+               bcp->congested_period = congested_period;
+       }
        return count;
 }
 
@@ -1097,6 +1268,11 @@ static int uv_ptc_proc_open(struct inode *inode, struct file *file)
        return seq_open(file, &uv_ptc_seq_ops);
 }
 
+static int tunables_open(struct inode *inode, struct file *file)
+{
+       return 0;
+}
+
 static const struct file_operations proc_uv_ptc_operations = {
        .open           = uv_ptc_proc_open,
        .read           = seq_read,
@@ -1105,6 +1281,12 @@ static const struct file_operations proc_uv_ptc_operations = {
        .release        = seq_release,
 };
 
+static const struct file_operations tunables_fops = {
+       .open           = tunables_open,
+       .read           = tunables_read,
+       .write          = tunables_write,
+};
+
 static int __init uv_ptc_init(void)
 {
        struct proc_dir_entry *proc_uv_ptc;
@@ -1119,6 +1301,20 @@ static int __init uv_ptc_init(void)
                       UV_PTC_BASENAME);
                return -EINVAL;
        }
+
+       tunables_dir = debugfs_create_dir(UV_BAU_TUNABLES_DIR, NULL);
+       if (!tunables_dir) {
+               printk(KERN_ERR "unable to create debugfs directory %s\n",
+                      UV_BAU_TUNABLES_DIR);
+               return -EINVAL;
+       }
+       tunables_file = debugfs_create_file(UV_BAU_TUNABLES_FILE, 0600,
+                       tunables_dir, NULL, &tunables_fops);
+       if (!tunables_file) {
+               printk(KERN_ERR "unable to create debugfs file %s\n",
+                      UV_BAU_TUNABLES_FILE);
+               return -EINVAL;
+       }
        return 0;
 }
 
@@ -1258,16 +1454,45 @@ static void __init uv_init_uvhub(int uvhub, int vector)
                                      ((apicid << 32) | vector));
 }
 
+/*
+ * We will set BAU_MISC_CONTROL with a timeout period.
+ * But the BIOS has set UVH_AGING_PRESCALE_SEL and UVH_TRANSACTION_TIMEOUT.
+ * So the destination timeout period has be be calculated from them.
+ */
+static int
+calculate_destination_timeout(void)
+{
+       unsigned long mmr_image;
+       int mult1;
+       int mult2;
+       int index;
+       int base;
+       int ret;
+       unsigned long ts_ns;
+
+       mult1 = UV_INTD_SOFT_ACK_TIMEOUT_PERIOD & BAU_MISC_CONTROL_MULT_MASK;
+       mmr_image = uv_read_local_mmr(UVH_AGING_PRESCALE_SEL);
+       index = (mmr_image >> BAU_URGENCY_7_SHIFT) & BAU_URGENCY_7_MASK;
+       mmr_image = uv_read_local_mmr(UVH_TRANSACTION_TIMEOUT);
+       mult2 = (mmr_image >> BAU_TRANS_SHIFT) & BAU_TRANS_MASK;
+       base = timeout_base_ns[index];
+       ts_ns = base * mult1 * mult2;
+       ret = ts_ns / 1000;
+       return ret;
+}
+
 /*
  * initialize the bau_control structure for each cpu
  */
 static void uv_init_per_cpu(int nuvhubs)
 {
-       int i, j, k;
+       int i;
        int cpu;
        int pnode;
        int uvhub;
        short socket = 0;
+       unsigned short socket_mask;
+       unsigned int uvhub_mask;
        struct bau_control *bcp;
        struct uvhub_desc *bdp;
        struct socket_desc *sdp;
@@ -1278,7 +1503,7 @@ static void uv_init_per_cpu(int nuvhubs)
                short cpu_number[16];
        };
        struct uvhub_desc {
-               short num_sockets;
+               unsigned short socket_mask;
                short num_cpus;
                short uvhub;
                short pnode;
@@ -1286,57 +1511,83 @@ static void uv_init_per_cpu(int nuvhubs)
        };
        struct uvhub_desc *uvhub_descs;
 
+       timeout_us = calculate_destination_timeout();
+
        uvhub_descs = (struct uvhub_desc *)
                kmalloc(nuvhubs * sizeof(struct uvhub_desc), GFP_KERNEL);
        memset(uvhub_descs, 0, nuvhubs * sizeof(struct uvhub_desc));
        for_each_present_cpu(cpu) {
                bcp = &per_cpu(bau_control, cpu);
                memset(bcp, 0, sizeof(struct bau_control));
-               spin_lock_init(&bcp->masks_lock);
-               bcp->max_concurrent = uv_bau_max_concurrent;
                pnode = uv_cpu_hub_info(cpu)->pnode;
                uvhub = uv_cpu_hub_info(cpu)->numa_blade_id;
+               uvhub_mask |= (1 << uvhub);
                bdp = &uvhub_descs[uvhub];
                bdp->num_cpus++;
                bdp->uvhub = uvhub;
                bdp->pnode = pnode;
-               /* time interval to catch a hardware stay-busy bug */
-               bcp->timeout_interval = millisec_2_cycles(3);
-               /* kludge: assume uv_hub.h is constant */
-               socket = (cpu_physical_id(cpu)>>5)&1;
-               if (socket >= bdp->num_sockets)
-                       bdp->num_sockets = socket+1;
+               /* kludge: 'assuming' one node per socket, and assuming that
+                  disabling a socket just leaves a gap in node numbers */
+               socket = (cpu_to_node(cpu) & 1);;
+               bdp->socket_mask |= (1 << socket);
                sdp = &bdp->socket[socket];
                sdp->cpu_number[sdp->num_cpus] = cpu;
                sdp->num_cpus++;
        }
-       socket = 0;
-       for_each_possible_blade(uvhub) {
+       uvhub = 0;
+       while (uvhub_mask) {
+               if (!(uvhub_mask & 1))
+                       goto nexthub;
                bdp = &uvhub_descs[uvhub];
-               for (i = 0; i < bdp->num_sockets; i++) {
-                       sdp = &bdp->socket[i];
-                       for (j = 0; j < sdp->num_cpus; j++) {
-                               cpu = sdp->cpu_number[j];
+               socket_mask = bdp->socket_mask;
+               socket = 0;
+               while (socket_mask) {
+                       if (!(socket_mask & 1))
+                               goto nextsocket;
+                       sdp = &bdp->socket[socket];
+                       for (i = 0; i < sdp->num_cpus; i++) {
+                               cpu = sdp->cpu_number[i];
                                bcp = &per_cpu(bau_control, cpu);
                                bcp->cpu = cpu;
-                               if (j == 0) {
+                               if (i == 0) {
                                        smaster = bcp;
-                                       if (i == 0)
+                                       if (socket == 0)
                                                hmaster = bcp;
                                }
                                bcp->cpus_in_uvhub = bdp->num_cpus;
                                bcp->cpus_in_socket = sdp->num_cpus;
                                bcp->socket_master = smaster;
+                               bcp->uvhub = bdp->uvhub;
                                bcp->uvhub_master = hmaster;
-                               for (k = 0; k < DEST_Q_SIZE; k++)
-                                       bcp->socket_acknowledge_count[k] = 0;
-                               bcp->uvhub_cpu =
-                                 uv_cpu_hub_info(cpu)->blade_processor_id;
+                               bcp->uvhub_cpu = uv_cpu_hub_info(cpu)->
+                                               blade_processor_id;
                        }
+nextsocket:
                        socket++;
+                       socket_mask = (socket_mask >> 1);
                }
+nexthub:
+               uvhub++;
+               uvhub_mask = (uvhub_mask >> 1);
        }
        kfree(uvhub_descs);
+       for_each_present_cpu(cpu) {
+               bcp = &per_cpu(bau_control, cpu);
+               bcp->baudisabled = 0;
+               bcp->statp = &per_cpu(ptcstats, cpu);
+               /* 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;
+               bcp->max_bau_concurrent_constant = max_bau_concurrent;
+               bcp->plugged_delay = plugged_delay;
+               bcp->plugsb4reset = plugsb4reset;
+               bcp->timeoutsb4reset = timeoutsb4reset;
+               bcp->ipi_reset_limit = ipi_reset_limit;
+               bcp->complete_threshold = complete_threshold;
+               bcp->congested_response_us = congested_response_us;
+               bcp->congested_reps = congested_reps;
+               bcp->congested_period = congested_period;
+       }
 }
 
 /*
@@ -1361,10 +1612,11 @@ static int __init uv_bau_init(void)
                zalloc_cpumask_var_node(&per_cpu(uv_flush_tlb_mask, cur_cpu),
                                       GFP_KERNEL, cpu_to_node(cur_cpu));
 
-       uv_bau_max_concurrent = MAX_BAU_CONCURRENT;
        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);
 
@@ -1383,15 +1635,19 @@ static int __init uv_bau_init(void)
        alloc_intr_gate(vector, uv_bau_message_intr1);
 
        for_each_possible_blade(uvhub) {
-               pnode = uv_blade_to_pnode(uvhub);
-               /* INIT the bau */
-               uv_write_global_mmr64(pnode, UVH_LB_BAU_SB_ACTIVATION_CONTROL,
-                                     ((unsigned long)1 << 63));
-               mmr = 1; /* should be 1 to broadcast to both sockets */
-               uv_write_global_mmr64(pnode, UVH_BAU_DATA_BROADCAST, mmr);
+               if (uv_blade_nr_possible_cpus(uvhub)) {
+                       pnode = uv_blade_to_pnode(uvhub);
+                       /* INIT the bau */
+                       uv_write_global_mmr64(pnode,
+                                       UVH_LB_BAU_SB_ACTIVATION_CONTROL,
+                                       ((unsigned long)1 << 63));
+                       mmr = 1; /* should be 1 to broadcast to both sockets */
+                       uv_write_global_mmr64(pnode, UVH_BAU_DATA_BROADCAST,
+                                               mmr);
+               }
        }
 
        return 0;
 }
 core_initcall(uv_bau_init);
-core_initcall(uv_ptc_init);
+fs_initcall(uv_ptc_init);