x86, UV: Improve BAU performance and error recovery

- increase performance of the interrupt handler

- release timed-out software acknowledge resources

- recover from continuous-busy status due to a hardware issue

- add a 'throttle' to keep a uvhub from sending more than a
  specified number of broadcasts concurrently (work around the hardware issue)

- provide a 'nobau' boot command line option

- rename 'pnode' and 'node' to 'uvhub' (the 'node' terminology
  is ambiguous)

- add some new statistics about the scope of broadcasts, retries, the
  hardware issue and the 'throttle'

- split off new function uv_bau_retry_msg() from
  uv_bau_process_message() per community coding style feedback.

- simplify the argument list to uv_bau_process_message(), per
  community coding style feedback.

Signed-off-by: Cliff Wickman <cpw@sgi.com>
Cc: linux-mm@kvack.org
Cc: Jack Steiner <steiner@sgi.com>
Cc: Russ Anderson <rja@sgi.com>
Cc: Mike Travis <travis@sgi.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <E1O25Z4-0004Ur-PB@eag09.americas.sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/include/asm/uv/uv_bau.h

@@ -27,13 +27,14 @@
  * set 2 is at BASE + 2*512, set 3 at BASE + 3*512, and so on.
  *
  * We will use 31 sets, one for sending BAU messages from each of the 32
- * cpu's on the node.
+ * cpu's on the uvhub.
  *
  * TLB shootdown will use the first of the 8 descriptors of each set.
  * Each of the descriptors is 64 bytes in size (8*64 = 512 bytes in a set).
  */
 
 #define UV_ITEMS_PER_DESCRIPTOR		8
+#define MAX_BAU_CONCURRENT		3
 #define UV_CPUS_PER_ACT_STATUS		32
 #define UV_ACT_STATUS_MASK		0x3
 #define UV_ACT_STATUS_SIZE		2
@@ -45,6 +46,9 @@
 #define UV_PAYLOADQ_PNODE_SHIFT		49
 #define UV_PTC_BASENAME			"sgi_uv/ptc_statistics"
 #define uv_physnodeaddr(x)		((__pa((unsigned long)(x)) & uv_mmask))
+#define UV_ENABLE_INTD_SOFT_ACK_MODE_SHIFT 15
+#define UV_INTD_SOFT_ACK_TIMEOUT_PERIOD_SHIFT 16
+#define UV_INTD_SOFT_ACK_TIMEOUT_PERIOD 0x000000000bUL
 
 /*
  * bits in UVH_LB_BAU_SB_ACTIVATION_STATUS_0/1
@@ -55,15 +59,29 @@
 #define DESC_STATUS_SOURCE_TIMEOUT	3
 
 /*
- * source side thresholds at which message retries print a warning
+ * source side threshholds at which message retries print a warning
  */
 #define SOURCE_TIMEOUT_LIMIT		20
 #define DESTINATION_TIMEOUT_LIMIT	20
 
+/*
+ * misc. delays, in microseconds
+ */
+#define THROTTLE_DELAY			10
+#define TIMEOUT_DELAY			10
+#define BIOS_TO				1000
+/* BIOS is assumed to set the destination timeout to 1003520 nanoseconds */
+
+/*
+ * threshholds at which to use IPI to free resources
+ */
+#define PLUGSB4RESET 100
+#define TIMEOUTSB4RESET 100
+
 /*
  * number of entries in the destination side payload queue
  */
-#define DEST_Q_SIZE			17
+#define DEST_Q_SIZE			20
 /*
  * number of destination side software ack resources
  */
@@ -72,9 +90,10 @@
 /*
  * completion statuses for sending a TLB flush message
  */
-#define	FLUSH_RETRY			1
+#define FLUSH_RETRY_PLUGGED		1
-#define	FLUSH_GIVEUP			2
+#define FLUSH_RETRY_TIMEOUT		2
-#define	FLUSH_COMPLETE			3
+#define FLUSH_GIVEUP			3
+#define FLUSH_COMPLETE			4
 
 /*
  * Distribution: 32 bytes (256 bits) (bytes 0-0x1f of descriptor)
@@ -86,14 +105,14 @@
  * 'base_dest_nodeid' field of the header corresponds to the
  * destination nodeID associated with that specified bit.
  */
-struct bau_target_nodemask {
+struct bau_target_uvhubmask {
-	unsigned long bits[BITS_TO_LONGS(256)];
+	unsigned long bits[BITS_TO_LONGS(UV_DISTRIBUTION_SIZE)];
 };
 
 /*
- * mask of cpu's on a node
+ * mask of cpu's on a uvhub
  * (during initialization we need to check that unsigned long has
- *  enough bits for max. cpu's per node)
+ *  enough bits for max. cpu's per uvhub)
  */
 struct bau_local_cpumask {
 	unsigned long bits;
@@ -135,8 +154,8 @@ struct bau_msg_payload {
 struct bau_msg_header {
 	unsigned int dest_subnodeid:6;	/* must be 0x10, for the LB */
 	/* bits 5:0 */
-	unsigned int base_dest_nodeid:15; /* nasid>>1 (pnode) of */
+	unsigned int base_dest_nodeid:15; /* nasid (pnode<<1) of */
-	/* bits 20:6 */			  /* first bit in node_map */
+	/* bits 20:6 */			  /* first bit in uvhub map */
 	unsigned int command:8;	/* message type */
 	/* bits 28:21 */
 				/* 0x38: SN3net EndPoint Message */
@@ -146,26 +165,38 @@ struct bau_msg_header {
 	unsigned int rsvd_2:9;	/* must be zero */
 	/* bits 40:32 */
 				/* Suppl_A is 56-41 */
-	unsigned int payload_2a:8;/* becomes byte 16 of msg */
+	unsigned int sequence:16;/* message sequence number */
-	/* bits 48:41 */	/* not currently using */
+	/* bits 56:41 */	/* becomes bytes 16-17 of msg */
-	unsigned int payload_2b:8;/* becomes byte 17 of msg */
-	/* bits 56:49 */	/* not currently using */
 				/* Address field (96:57) is never used as an
 				   address (these are address bits 42:3) */
+
 	unsigned int rsvd_3:1;	/* must be zero */
 	/* bit 57 */
 				/* address bits 27:4 are payload */
-				/* these 24 bits become bytes 12-14 of msg */
+	/* these next 24  (58-81) bits become bytes 12-14 of msg */
+
+	/* bits 65:58 land in byte 12 */
 	unsigned int replied_to:1;/* sent as 0 by the source to byte 12 */
 	/* bit 58 */
+	unsigned int msg_type:3; /* software type of the message*/
+	/* bits 61:59 */
+	unsigned int canceled:1; /* message canceled, resource to be freed*/
+	/* bit 62 */
+	unsigned int payload_1a:1;/* not currently used */
+	/* bit 63 */
+	unsigned int payload_1b:2;/* not currently used */
+	/* bits 65:64 */
 
-	unsigned int payload_1a:5;/* not currently used */
+	/* bits 73:66 land in byte 13 */
-	/* bits 63:59 */
+	unsigned int payload_1ca:6;/* not currently used */
-	unsigned int payload_1b:8;/* not currently used */
+	/* bits 71:66 */
-	/* bits 71:64 */
+	unsigned int payload_1c:2;/* not currently used */
-	unsigned int payload_1c:8;/* not currently used */
+	/* bits 73:72 */
-	/* bits 79:72 */
+
-	unsigned int payload_1d:2;/* not currently used */
+	/* bits 81:74 land in byte 14 */
+	unsigned int payload_1d:6;/* not currently used */
+	/* bits 79:74 */
+	unsigned int payload_1e:2;/* not currently used */
 	/* bits 81:80 */
 
 	unsigned int rsvd_4:7;	/* must be zero */
@@ -178,7 +209,7 @@ struct bau_msg_header {
 	/* bits 95:90 */
 	unsigned int rsvd_6:5;	/* must be zero */
 	/* bits 100:96 */
-	unsigned int int_both:1;/* if 1, interrupt both sockets on the blade */
+	unsigned int int_both:1;/* if 1, interrupt both sockets on the uvhub */
 	/* bit 101*/
 	unsigned int fairness:3;/* usually zero */
 	/* bits 104:102 */
@@ -191,13 +222,18 @@ struct bau_msg_header {
 	/* bits 127:107 */
 };
 
+/* see msg_type: */
+#define MSG_NOOP 0
+#define MSG_REGULAR 1
+#define MSG_RETRY 2
+
 /*
  * The activation descriptor:
  * The format of the message to send, plus all accompanying control
  * Should be 64 bytes
  */
 struct bau_desc {
-	struct bau_target_nodemask distribution;
+	struct bau_target_uvhubmask distribution;
 	/*
 	 * message template, consisting of header and payload:
 	 */
@@ -237,19 +273,25 @@ struct bau_payload_queue_entry {
 	unsigned short acknowledge_count; /* filled in by destination */
 	/* 16 bits, bytes 10-11 */
 
-	unsigned short replied_to:1;	/* sent as 0 by the source */
+	/* these next 3 bytes come from bits 58-81 of the message header */
-	/* 1 bit */
+	unsigned short replied_to:1;    /* sent as 0 by the source */
-	unsigned short unused1:7;       /* not currently using */
+	unsigned short msg_type:3;      /* software message type */
-	/* 7 bits: byte 12) */
+	unsigned short canceled:1;      /* sent as 0 by the source */
+	unsigned short unused1:3;       /* not currently using */
+	/* byte 12 */
 
-	unsigned char unused2[2];	/* not currently using */
+	unsigned char unused2a;		/* not currently using */
-	/* bytes 13-14 */
+	/* byte 13 */
+	unsigned char unused2;		/* not currently using */
+	/* byte 14 */
 
 	unsigned char sw_ack_vector;	/* filled in by the hardware */
 	/* byte 15 (bits 127:120) */
 
-	unsigned char unused4[3];	/* not currently using bytes 17-19 */
+	unsigned short sequence;	/* message sequence number */
-	/* bytes 17-19 */
+	/* bytes 16-17 */
+	unsigned char unused4[2];	/* not currently using bytes 18-19 */
+	/* bytes 18-19 */
 
 	int number_of_cpus;		/* filled in at destination */
 	/* 32 bits, bytes 20-23 (aligned) */
@@ -259,63 +301,93 @@ struct bau_payload_queue_entry {
 };
 
 /*
- * one for every slot in the destination payload queue
+ * one per-cpu; to locate the software tables
- */
-struct bau_msg_status {
-	struct bau_local_cpumask seen_by;	/* map of cpu's */
-};
-
-/*
- * one for every slot in the destination software ack resources
- */
-struct bau_sw_ack_status {
-	struct bau_payload_queue_entry *msg;	/* associated message */
-	int watcher;				/* cpu monitoring, or -1 */
-};
-
-/*
- * one on every node and per-cpu; to locate the software tables
  */
 struct bau_control {
 	struct bau_desc *descriptor_base;
-	struct bau_payload_queue_entry *bau_msg_head;
 	struct bau_payload_queue_entry *va_queue_first;
 	struct bau_payload_queue_entry *va_queue_last;
-	struct bau_msg_status *msg_statuses;
+	struct bau_payload_queue_entry *bau_msg_head;
-	int *watching; /* pointer to array */
+	struct bau_control *uvhub_master;
+	struct bau_control *socket_master;
+	unsigned long timeout_interval;
+	atomic_t active_descriptor_count;
+	int max_concurrent;
+	int max_concurrent_constant;
+	int retry_message_scans;
+	int plugged_tries;
+	int timeout_tries;
+	int ipi_attempts;
+	int conseccompletes;
+	short cpu;
+	short uvhub_cpu;
+	short uvhub;
+	short cpus_in_socket;
+	short cpus_in_uvhub;
+	unsigned short message_number;
+	unsigned short uvhub_quiesce;
+	short socket_acknowledge_count[DEST_Q_SIZE];
+	cycles_t send_message;
+	spinlock_t masks_lock;
+	spinlock_t uvhub_lock;
+	spinlock_t queue_lock;
 };
 
 /*
  * This structure is allocated per_cpu for UV TLB shootdown statistics.
  */
 struct ptc_stats {
-	unsigned long ptc_i;	/* number of IPI-style flushes */
+	/* sender statistics */
-	unsigned long requestor;	/* number of nodes this cpu sent to */
+	unsigned long s_giveup; /* number of fall backs to IPI-style flushes */
-	unsigned long requestee;	/* times cpu was remotely requested */
+	unsigned long s_requestor; /* number of shootdown requests */
-	unsigned long alltlb;	/* times all tlb's on this cpu were flushed */
+	unsigned long s_stimeout; /* source side timeouts */
-	unsigned long onetlb;	/* times just one tlb on this cpu was flushed */
+	unsigned long s_dtimeout; /* destination side timeouts */
-	unsigned long s_retry;	/* retries on source side timeouts */
+	unsigned long s_time; /* time spent in sending side */
-	unsigned long d_retry;	/* retries on destination side timeouts */
+	unsigned long s_retriesok; /* successful retries */
-	unsigned long sflush;	/* cycles spent in uv_flush_tlb_others */
+	unsigned long s_ntargcpu; /* number of cpus targeted */
-	unsigned long dflush;	/* cycles spent on destination side */
+	unsigned long s_ntarguvhub; /* number of uvhubs targeted */
-	unsigned long retriesok; /* successes on retries */
+	unsigned long s_ntarguvhub16; /* number of times >= 16 target hubs */
-	unsigned long nomsg;	/* interrupts with no message */
+	unsigned long s_ntarguvhub8; /* number of times >= 8 target hubs */
-	unsigned long multmsg;	/* interrupts with multiple messages */
+	unsigned long s_ntarguvhub4; /* number of times >= 4 target hubs */
-	unsigned long ntargeted;/* nodes targeted */
+	unsigned long s_ntarguvhub2; /* number of times >= 2 target hubs */
+	unsigned long s_ntarguvhub1; /* number of times == 1 target hub */
+	unsigned long s_resets_plug; /* ipi-style resets from plug state */
+	unsigned long s_resets_timeout; /* ipi-style resets from timeouts */
+	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 */
+	/* 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 */
+	unsigned long d_multmsg; /* interrupts with multiple messages */
+	unsigned long d_nomsg; /* interrupts with no message */
+	unsigned long d_time; /* time spent on destination side */
+	unsigned long d_requestee; /* number of messages processed */
+	unsigned long d_retries; /* number of retry messages processed */
+	unsigned long d_canceled; /* number of messages canceled by retries */
+	unsigned long d_nocanceled; /* retries that found nothing to cancel */
+	unsigned long d_resets; /* number of ipi-style requests processed */
+	unsigned long d_rcanceled; /* number of messages canceled by resets */
 };
 
-static inline int bau_node_isset(int node, struct bau_target_nodemask *dstp)
+static inline int bau_uvhub_isset(int uvhub, struct bau_target_uvhubmask *dstp)
 {
-	return constant_test_bit(node, &dstp->bits[0]);
+	return constant_test_bit(uvhub, &dstp->bits[0]);
 }
-static inline void bau_node_set(int node, struct bau_target_nodemask *dstp)
+static inline void bau_uvhub_set(int uvhub, struct bau_target_uvhubmask *dstp)
 {
-	__set_bit(node, &dstp->bits[0]);
+	__set_bit(uvhub, &dstp->bits[0]);
 }
-static inline void bau_nodes_clear(struct bau_target_nodemask *dstp, int nbits)
+static inline void bau_uvhubs_clear(struct bau_target_uvhubmask *dstp,
+				    int nbits)
 {
 	bitmap_zero(&dstp->bits[0], nbits);
 }
+static inline int bau_uvhub_weight(struct bau_target_uvhubmask *dstp)
+{
+	return bitmap_weight((unsigned long *)&dstp->bits[0],
+				UV_DISTRIBUTION_SIZE);
+}
 
 static inline void bau_cpubits_clear(struct bau_local_cpumask *dstp, int nbits)
 {
@@ -328,4 +400,35 @@ static inline void bau_cpubits_clear(struct bau_local_cpumask *dstp, int nbits)
 extern void uv_bau_message_intr1(void);
 extern void uv_bau_timeout_intr1(void);
 
+struct atomic_short {
+	short counter;
+};
+
+/**
+ * atomic_read_short - read a short atomic variable
+ * @v: pointer of type atomic_short
+ *
+ * Atomically reads the value of @v.
+ */
+static inline int atomic_read_short(const struct atomic_short *v)
+{
+	return v->counter;
+}
+
+/**
+ * atomic_add_short_return - add and return a short int
+ * @i: short value to add
+ * @v: pointer of type atomic_short
+ *
+ * Atomically adds @i to @v and returns @i + @v
+ */
+static inline int atomic_add_short_return(short i, struct atomic_short *v)
+{
+	short __i = i;
+	asm volatile(LOCK_PREFIX "xaddw %0, %1"
+			: "+r" (i), "+m" (v->counter)
+			: : "memory");
+	return i + __i;
+}
+
 #endif /* _ASM_X86_UV_UV_BAU_H */