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homa_utils.c
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/* Copyright (c) 2019-2020 Stanford University
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/* This file contains miscellaneous utility functions for the Homa protocol. */
#include "homa_impl.h"
/* Core-specific information. NR_CPUS is an overestimate of the actual
* number, but allows us to allocate the array statically.
*/
struct homa_core *homa_cores[NR_CPUS];
/* Points to block of memory holding all homa_cores; used to free it. */
char *core_memory;
/**
* homa_init() - Constructor for homa objects.
* @homa: Object to initialize.
*
* Return: 0 on success, or a negative errno if there was an error. Even
* if an error occurs, it is safe (and necessary) to call
* homa_destroy at some point.
*/
int homa_init(struct homa *homa)
{
size_t aligned_size;
char *first;
int i, err;
_Static_assert(HOMA_MAX_PRIORITIES >= 8,
"homa_init assumes at least 8 priority levels");
/* Initialize core-specific info (if no-one else has already done it),
* making sure that each core has private cache lines.
*/
if (!core_memory) {
aligned_size = (sizeof(struct homa_core) + 0x3f) & ~0x3f;
core_memory = vmalloc(0x3f + (nr_cpu_ids*aligned_size));
if (!core_memory) {
printk(KERN_ERR "Homa couldn't allocate memory "
"for core-specific data\n");
return -ENOMEM;
}
first = (char *) (((__u64) core_memory + 0x3f) & ~0x3f);
for (i = 0; i < nr_cpu_ids; i++) {
homa_cores[i] = (struct homa_core *)
(first + i*aligned_size);
memset(homa_cores[i], 0, aligned_size);
}
}
homa->pacer_kthread = NULL;
homa->next_client_port = HOMA_MIN_CLIENT_PORT;
atomic64_set(&homa->next_outgoing_id, 1);
homa_socktab_init(&homa->port_map);
err = homa_peertab_init(&homa->peers);
if (err) {
printk(KERN_ERR "Couldn't initialize peer table (errno %d)\n",
-err);
return err;
}
/* Wild guesses to initialize configuration values... */
homa->rtt_bytes = 10000;
homa->link_mbps = 10000;
homa->poll_usecs = 100;
homa->num_priorities = HOMA_MAX_PRIORITIES;
for (i = 0; i < HOMA_MAX_PRIORITIES; i++)
homa->priority_map[i] = i;
homa->max_sched_prio = HOMA_MAX_PRIORITIES - 5;
homa->unsched_cutoffs[HOMA_MAX_PRIORITIES-1] = 200;
homa->unsched_cutoffs[HOMA_MAX_PRIORITIES-2] = 2800;
homa->unsched_cutoffs[HOMA_MAX_PRIORITIES-3] = 15000;
homa->unsched_cutoffs[HOMA_MAX_PRIORITIES-4] = HOMA_MAX_MESSAGE_LENGTH;
#ifdef __UNIT_TEST__
/* Unit tests won't send CUTOFFS messages unless the test changes
* this variable.
*/
homa->cutoff_version = 0;
#else
homa->cutoff_version = 1;
#endif
homa->grant_increment = 0;
homa->max_overcommit = 8;
homa->resend_ticks = 2;
homa->resend_interval = 5;
homa->timeout_resends = 10;
homa->rpc_discard_ticks = 50;
homa->reap_limit = 10;
homa->max_dead_buffs = 10000;
spin_lock_init(&homa->grantable_lock);
INIT_LIST_HEAD(&homa->grantable_peers);
homa->num_grantable_peers = 0;
spin_lock_init(&homa->throttle_lock);
INIT_LIST_HEAD_RCU(&homa->throttled_rpcs);
homa->throttle_min_bytes = 1000;
homa->pacer_kthread = kthread_run(homa_pacer_main, homa,
"homa_pacer");
if (IS_ERR(homa->pacer_kthread)) {
err = PTR_ERR(homa->pacer_kthread);
homa->pacer_kthread = NULL;
printk(KERN_ERR "couldn't create homa pacer thread: error %d\n",
err);
return err;
}
homa->pacer_exit = false;
atomic_set(&homa->pacer_active, 0);
atomic64_set(&homa->link_idle_time, get_cycles());
homa->max_nic_queue_ns = 2000;
homa->cycles_per_kbyte = 0;
homa->verbose = 0;
homa->max_gso_size = 1000000;
homa->max_gro_skbs = 20;
homa->gro_policy = HOMA_GRO_NORMAL;
homa->timer_ticks = 0;
spin_lock_init(&homa->metrics_lock);
homa->metrics = NULL;
homa->metrics_capacity = 0;
homa->metrics_length = 0;
homa->metrics_active_opens = 0;
homa_outgoing_sysctl_changed(homa);
return 0;
}
/**
* homa_destroy() - Destructor for homa objects.
* @homa: Object to destroy.
*/
void homa_destroy(struct homa *homa)
{
int i;
if (homa->pacer_kthread) {
homa_pacer_stop(homa);
}
/* The order of the following 2 statements matters! */
homa_socktab_destroy(&homa->port_map);
homa_peertab_destroy(&homa->peers);
if (core_memory) {
vfree(core_memory);
core_memory = NULL;
for (i = 0; i < nr_cpu_ids; i++) {
homa_cores[i] = NULL;
}
}
if (homa->metrics)
kfree(homa->metrics);
}
/**
* homa_rpc_new_client() - Allocate and construct a client RPC (one that is used
* to issue an outgoing request). Doesn't send any packets. Invoked with no
* locks held.
* @hsk: Socket to which the RPC belongs.
* @dest: Address of host (ip and port) to which the RPC will be sent.
* @buffer: Address (in user space) of the first byte of the request message.
* @len: Number of bytes in the request message.
*
* Return: A printer to the newly allocated object, or a negative
* errno if an error occurred. The RPC will be locked; the
* caller must eventually unlock it.
*/
struct homa_rpc *homa_rpc_new_client(struct homa_sock *hsk,
struct sockaddr_in *dest, void __user *buffer, size_t len)
{
int err;
struct homa_rpc *crpc;
struct homa_rpc_bucket *bucket;
struct sk_buff *skb = NULL;
crpc = (struct homa_rpc *) kmalloc(sizeof(*crpc), GFP_KERNEL);
if (unlikely(!crpc))
return ERR_PTR(-ENOMEM);
/* Initialize fields that don't require the socket lock. */
crpc->hsk = hsk;
crpc->id = atomic64_fetch_add(1, &hsk->homa->next_outgoing_id);
crpc->generation = 1;
bucket = homa_client_rpc_bucket(hsk, crpc->id);
crpc->lock = &bucket->lock;
crpc->state = RPC_OUTGOING;
crpc->is_client = true;
crpc->dont_reap = false;
atomic_set(&crpc->grants_in_progress, 0);
crpc->peer = homa_peer_find(&hsk->homa->peers,
dest->sin_addr.s_addr, &hsk->inet);
if (unlikely(IS_ERR(crpc->peer))) {
tt_record("error in homa_peer_find");
err = PTR_ERR(crpc->peer);
goto error;
}
crpc->dport = ntohs(dest->sin_port);
crpc->error = 0;
crpc->msgin.total_length = -1;
crpc->msgin.num_skbs = 0;
skb = homa_fill_packets(hsk, crpc->peer, buffer, len);
if (IS_ERR(skb)) {
err = PTR_ERR(skb);
tt_record1("error in homa_fill_packets: %d", err);
skb = NULL;
goto error;
}
homa_message_out_init(crpc, hsk->client_port, skb, len);
INIT_LIST_HEAD(&crpc->dead_links);
crpc->interest = NULL;
INIT_LIST_HEAD(&crpc->ready_links);
INIT_LIST_HEAD(&crpc->grantable_links);
INIT_LIST_HEAD(&crpc->throttled_links);
crpc->silent_ticks = 0;
crpc->magic = HOMA_RPC_MAGIC;
/* Initialize fields that require locking. This allows the most
* expensive work, such as copying in the message from user space,
* to be performed without holding locks. Also, can't hold spin
* locks while doing things that could block, such as memory allocation.
*/
homa_bucket_lock(bucket, client);
homa_sock_lock(hsk, "homa_rpc_new_client");
if (hsk->shutdown) {
homa_sock_unlock(hsk);
homa_rpc_unlock(crpc);
err = -ESHUTDOWN;
goto error;
}
hlist_add_head(&crpc->hash_links, &bucket->rpcs);
list_add_tail_rcu(&crpc->active_links, &hsk->active_rpcs);
homa_sock_unlock(hsk);
return crpc;
error:
homa_free_skbs(skb);
kfree(crpc);
return ERR_PTR(err);
}
/**
* homa_rpc_new_server() - Allocate and construct a server RPC (one that is
* used to manage an incoming request).
* @hsk: Socket that owns this RPC.
* @source: IP address (network byte order) of the RPC's client.
* @h: Header for the first data packet received for this RPC; used
* to initialize the RPC.
*
* Return: A pointer to a new RPC, which is locked, or a negative errno
* if an error occurred. If there is already an RPC corresponding
* to h, then it is returned instead of creating a new RPC.
* If a new RPC is created, it is not yet linked into
* @hsk->active_rpcs.
*/
struct homa_rpc *homa_rpc_new_server(struct homa_sock *hsk,
__be32 source, struct data_header *h)
{
int err;
struct homa_rpc *srpc;
struct homa_rpc_bucket *bucket = homa_server_rpc_bucket(hsk,
h->common.id);
/* Lock the bucket, and make sure no-one else has already created
* the desired RPC.
*/
homa_bucket_lock(bucket, server);
hlist_for_each_entry_rcu(srpc, &bucket->rpcs, hash_links) {
if ((srpc->id == h->common.id) &&
(srpc->dport == ntohs(h->common.sport)) &&
(srpc->peer->addr == source)) {
/* RPC already exists; just return it instead
* of creating a new RPC.
*/
return srpc;
}
}
/* Initialize fields that don't require the socket lock. */
srpc = (struct homa_rpc *) kmalloc(sizeof(*srpc), GFP_KERNEL);
if (!srpc) {
err = -ENOMEM;
goto error;
}
srpc->hsk = hsk;
srpc->lock = &bucket->lock;
srpc->state = RPC_INCOMING;
srpc->is_client = false;
srpc->dont_reap = false;
atomic_set(&srpc->grants_in_progress, 0);
srpc->peer = homa_peer_find(&hsk->homa->peers, source, &hsk->inet);
if (unlikely(IS_ERR(srpc->peer))) {
err = PTR_ERR(srpc->peer);
kfree(srpc);
goto error;
}
srpc->dport = ntohs(h->common.sport);
srpc->id = h->common.id;
srpc->generation = ntohs(h->common.generation);
srpc->error = 0;
homa_message_in_init(&srpc->msgin, ntohl(h->message_length),
ntohl(h->incoming));
srpc->msgout.length = -1;
srpc->msgout.num_skbs = 0;
srpc->active_links.next = LIST_POISON1;
srpc->interest = NULL;
INIT_LIST_HEAD(&srpc->ready_links);
INIT_LIST_HEAD(&srpc->grantable_links);
INIT_LIST_HEAD(&srpc->throttled_links);
srpc->silent_ticks = 0;
srpc->magic = HOMA_RPC_MAGIC;
hlist_add_head(&srpc->hash_links, &bucket->rpcs);
return srpc;
error:
spin_unlock_bh(&bucket->lock);
return ERR_PTR(err);
}
/**
* homa_rpc_lock_slow() - This function implements the slow path for
* acquiring an RPC lock. It is invoked when an RPC lock isn't immediately
* available. It waits for the lock, but also records statistics about
* the waiting time.
* @rpc: RPC to lock.
*/
void homa_rpc_lock_slow(struct homa_rpc *rpc)
{
__u64 start = get_cycles();
spin_lock_bh(rpc->lock);
if (rpc->is_client) {
INC_METRIC(client_lock_misses, 1);
INC_METRIC(client_lock_miss_cycles, get_cycles() - start);
} else {
INC_METRIC(server_lock_misses, 1);
INC_METRIC(server_lock_miss_cycles, get_cycles() - start);
}
}
/**
* homa_rpc_free() - Destructor for homa_rpc; will arrange for all resources
* associated with the RPC to be released (eventually).
* @rpc: Structure to clean up, or NULL. Must be locked. Its socket must
* not be locked.
*/
void homa_rpc_free(struct homa_rpc *rpc)
{
if (!rpc || (rpc->state == RPC_DEAD))
return;
/* Before doing anything else, unlink the input message from
* homa->grantable_msgs. This will synchronize to ensure that
* homa_manage_grants doesn't access this RPC after destruction
* begins.
*/
homa_remove_from_grantable(rpc->hsk->homa, rpc);
/* Unlink from all lists, so no-one will ever find this RPC again. */
homa_sock_lock(rpc->hsk, "homa_rpc_free");
__hlist_del(&rpc->hash_links);
list_del_rcu(&rpc->active_links);
__list_del_entry(&rpc->ready_links);
if (rpc->interest != NULL) {
rpc->interest->reg_rpc = NULL;
wake_up_process(rpc->interest->thread);
rpc->interest = NULL;
}
list_add_tail_rcu(&rpc->dead_links, &rpc->hsk->dead_rpcs);
rpc->hsk->dead_skbs += rpc->msgin.num_skbs + rpc->msgout.num_skbs;
tt_record3("Freeing rpc id %d, socket %d, dead_skbs %d", rpc->id,
rpc->hsk->client_port,
rpc->hsk->dead_skbs);
rpc->state = RPC_DEAD;
homa_sock_unlock(rpc->hsk);
if (unlikely(!list_empty(&rpc->throttled_links))) {
homa_throttle_lock(rpc->hsk->homa);
list_del(&rpc->throttled_links);
INIT_LIST_HEAD(&rpc->throttled_links);
homa_throttle_unlock(rpc->hsk->homa);
}
}
/**
* homa_rpc_reap() - Invoked to release resources associated with dead
* RPCs for a given socket. For a large RPC, it can take a long time to
* free all of its packet buffers, so we try to perform this work
* off the critical path where it won't delay applications. Each call to
* this function does a small chunk of work.
* @hsk: Homa socket that may contain dead RPCs. Must not be locked by the
* caller; this function will lock and release.
*
* Return: A return value of 0 means that we reaped everything we possibly
* could; calling again will do no work (there could be unreaped RPCs,
* but if so, reaping has been disabled for them). A value greater than
* zero means there is still more reaping work to be done.
*/
int homa_rpc_reap(struct homa_sock *hsk)
{
struct sk_buff *skbs[hsk->homa->reap_limit];
struct homa_rpc *rpcs[hsk->homa->reap_limit];
int num_skbs = 0;
int num_rpcs = 0;
struct homa_rpc *rpc;
int i, result;
homa_sock_lock(hsk, "homa_rpc_reap");
if (atomic_read(&hsk->protect_count)) {
INC_METRIC(disabled_reaps, 1);
homa_sock_unlock(hsk);
return 0;
}
INC_METRIC(reaper_calls, 1);
INC_METRIC(reaper_dead_skbs, hsk->dead_skbs);
/* Collect buffers and freeable RPCs until either we hit our limit
* or run out of RPCs.
*/
tt_record2("Starting homa_rpc_reap, dead_skbs %d, port %d",
hsk->dead_skbs, hsk->client_port);
list_for_each_entry_rcu(rpc, &hsk->dead_rpcs, dead_links) {
if (rpc->dont_reap || (atomic_read(&rpc->grants_in_progress)
!= 0)) {
INC_METRIC(disabled_rpc_reaps, 1);
continue;
}
if (rpc->msgout.packets)
tt_record2("Reaping rpc msgout, id %d, peer 0x%x",
rpc->id, ntohl(rpc->peer->addr));
else
tt_record2("Reaping rpc msgin, id %d, peer 0x%x",
rpc->id, ntohl(rpc->peer->addr));
rpc->magic = 0;
if (rpc->msgout.length >= 0) {
while (rpc->msgout.packets) {
skbs[num_skbs] = rpc->msgout.packets;
rpc->msgout.packets = *homa_next_skb(
rpc->msgout.packets);
num_skbs++;
rpc->msgout.num_skbs--;
if (num_skbs >= hsk->homa->reap_limit)
goto release;
}
}
i = 0;
if (rpc->msgin.total_length >= 0) {
while (1) {
struct sk_buff *skb;
skb = skb_dequeue(
&rpc->msgin.packets);
if (!skb)
break;
skbs[num_skbs] = skb;
num_skbs++;
rpc->msgin.num_skbs--;
if (num_skbs >= hsk->homa->reap_limit)
goto release;
}
}
/* If we get here, it means all packets have been removed
* from the RPC.
*/
rpcs[num_rpcs] = rpc;
num_rpcs++;
list_del_rcu(&rpc->dead_links);
}
/* Free all of the collected resources; release the socket
* lock while doing this.
*/
release:
tt_record2("reaping %d skbs, %d rpcs", num_skbs, num_rpcs);
hsk->dead_skbs -= num_skbs;
result = !list_empty(&hsk->dead_rpcs) && ((num_skbs + num_rpcs) != 0);
homa_sock_unlock(hsk);
for (i = 0; i < num_skbs; i++) {
kfree_skb(skbs[i]);
}
for (i = 0; i < num_rpcs; i++) {
UNIT_LOG("; ", "reaped %llu", rpcs[i]->id);
/* Lock and unlock the RPC before freeing it. This is needed
* to deal with races where the last user of the RPC (such
* as homa_ioc_reply) hasn't unlocked it yet.
*/
homa_rpc_lock(rpcs[i]);
homa_rpc_unlock(rpcs[i]);
rpcs[i]->state = 0;
kfree(rpcs[i]);
}
return result;
}
/**
* homa_find_client_rpc() - Locate client-side information about the RPC that
* a packet belongs to, if there is any. Thread-safe without socket lock.
* @hsk: Socket via which packet was received.
* @id: Unique identifier for the RPC.
*
* Return: A pointer to the homa_rpc for this id, or NULL if none.
* The RPC will be locked; the caller must eventually unlock it
* by invoking homa_unlock_client_rpc.
*/
struct homa_rpc *homa_find_client_rpc(struct homa_sock *hsk, __u64 id)
{
struct homa_rpc *crpc;
struct homa_rpc_bucket *bucket = homa_client_rpc_bucket(hsk, id);
homa_bucket_lock(bucket, client);
hlist_for_each_entry_rcu(crpc, &bucket->rpcs, hash_links) {
if (crpc->id == id) {
return crpc;
}
}
spin_unlock_bh(&bucket->lock);
return NULL;
}
/**
* homa_find_server_rpc() - Locate server-side information about the RPC that
* a packet belongs to, if there is any. Thread-safe without socket lock.
* @hsk: Socket via which packet was received.
* @saddr: Address from which the packet was sent.
* @sport: Port at @saddr from which the packet was sent.
* @id: Unique identifier for the RPC.
*
* Return: A pointer to the homa_rpc matching the arguments, or NULL
* if none. The RPC will be locked; the caller must eventually
* unlock it by invoking homa_unlock_server_rpc.
*/
struct homa_rpc *homa_find_server_rpc(struct homa_sock *hsk,
__be32 saddr, __u16 sport, __u64 id)
{
struct homa_rpc *srpc;
struct homa_rpc_bucket *bucket = homa_server_rpc_bucket(hsk, id);
homa_bucket_lock(bucket, server);
hlist_for_each_entry_rcu(srpc, &bucket->rpcs, hash_links) {
if ((srpc->id == id) && (srpc->dport == sport) &&
(srpc->peer->addr == saddr)) {
return srpc;
}
}
spin_unlock_bh(&bucket->lock);
return NULL;
}
/**
* homa_rpc_log() - Log info about a particular RPC; this is functionality
* pulled out of homa_rpc_log_active because its indentation got too deep.
* @rpc: RPC for which key info should be written to the system log.
*/
void homa_rpc_log(struct homa_rpc *rpc)
{
char *type = (rpc->is_client) ? "Client" : "Server";
char *peer = homa_print_ipv4_addr(rpc->peer->addr);
if (rpc->state == RPC_INCOMING)
printk(KERN_NOTICE "%s RPC INCOMING, id %llu, peer %s:%d, "
"generation %d, %d/%d bytes received, "
"incoming %d\n",
type, rpc->id, peer, rpc->dport,
rpc->generation, rpc->msgin.total_length
- rpc->msgin.bytes_remaining,
rpc->msgin.total_length, rpc->msgin.incoming);
else if (rpc->state == RPC_OUTGOING) {
int offset;
if (rpc->msgout.next_packet != NULL) {
struct data_header *h = (struct data_header *)
rpc->msgout.next_packet->data;
offset = ntohl(h->seg.offset);
} else
offset = rpc->msgout.length;
printk(KERN_NOTICE "%s RPC OUTGOING, id %llu, peer %s:%d, "
"generation %d, outgoing length %d, "
"granted %d, next xmit offset %d, "
"incoming bytes left %d\n",
type, rpc->id, peer, rpc->dport,
rpc->generation, rpc->msgout.length,
rpc->msgout.granted, offset,
rpc->msgin.bytes_remaining);
} else
printk(KERN_NOTICE "%s RPC %s, id %llu, peer %s:%d, "
"generation %d, incoming length %d, "
"outgoing length %d\n",
type, homa_symbol_for_state(rpc),
rpc->id, peer, rpc->dport, rpc->generation,
rpc->msgin.total_length, rpc->msgout.length);
}
/**
* homa_rpc_log_active() - Print information to the system log about all
* active RPCs. Intended primarily for debugging.
* @homa: Overall data about the Homa protocol implementation.
* @id: An RPC id: if nonzero, then only RPCs with this id will be
* logged.
*/
void homa_rpc_log_active(struct homa *homa, uint64_t id)
{
struct homa_socktab_scan scan;
struct homa_sock *hsk;
struct homa_rpc *rpc;
int count = 0;
printk("Logging active Homa RPCs:\n");
rcu_read_lock();
for (hsk = homa_socktab_start_scan(&homa->port_map, &scan);
hsk != NULL; hsk = homa_socktab_next(&scan)) {
if (list_empty(&hsk->active_rpcs) || hsk->shutdown)
continue;
if (!homa_protect_rpcs(hsk))
continue;
list_for_each_entry_rcu(rpc, &hsk->active_rpcs, active_links) {
count++;
if ((id != 0) && (id != rpc->id))
continue;
homa_rpc_log(rpc);
}
homa_unprotect_rpcs(hsk);
}
rcu_read_unlock();
printk("Finished logging active Homa RPCs: %d active RPCs\n", count);
}
/**
* homa_print_ipv4_addr() - Convert an IPV4 address to the standard string
* representation.
* @addr: Address to convert, in network byte order.
*
* Return: The converted value. Values are stored in static memory, so
* the caller need not free. This also means that storage is
* eventually reused (there are enough buffers to accommodate
* multiple "active" values).
*
* Note: Homa uses this function, rather than the %pI4 format specifier
* for snprintf et al., because the kernel's version of snprintf isn't
* available in Homa's unit test environment.
*/
char *homa_print_ipv4_addr(__be32 addr)
{
#define NUM_BUFS 4
#define BUF_SIZE 30
static char buffers[NUM_BUFS][BUF_SIZE];
static int next_buf = 0;
__u32 a2 = ntohl(addr);
char *buffer = buffers[next_buf];
next_buf++;
if (next_buf >= NUM_BUFS)
next_buf = 0;
snprintf(buffer, BUF_SIZE, "%u.%u.%u.%u", (a2 >> 24) & 0xff,
(a2 >> 16) & 0xff, (a2 >> 8) & 0xff, a2 & 0xff);
return buffer;
}
/**
* homa_print_packet() - Print a human-readable string describing the
* information in a Homa packet.
* @skb: Packet whose information should be printed.
* @buffer: Buffer in which to generate the string.
* @buf_len: Number of bytes available at @buffer.
*
* Return: @buffer
*/
char *homa_print_packet(struct sk_buff *skb, char *buffer, int buf_len)
{
int used = 0;
struct common_header *common = (struct common_header *) skb->data;
used = homa_snprintf(buffer, buf_len, used,
"%s from %s:%u, dport %d, id %llu",
homa_symbol_for_type(common->type),
homa_print_ipv4_addr(ip_hdr(skb)->saddr),
ntohs(common->sport), ntohs(common->dport), common->id);
if (ntohs(common->generation) != 1)
used = homa_snprintf(buffer, buf_len, used, ", generation %d",
ntohs(common->generation));
switch (common->type) {
case DATA: {
struct data_header *h = (struct data_header *)
skb->data;
struct data_segment *seg;
int seg_length = ntohl(h->seg.segment_length);
int bytes_left, i;
used = homa_snprintf(buffer, buf_len, used,
", message_length %d, offset %d, "
"data_length %d, incoming %d",
ntohl(h->message_length),
ntohl(h->seg.offset), seg_length,
ntohl(h->incoming));
if (ntohs(h->cutoff_version != 0))
used = homa_snprintf(buffer, buf_len, used,
", cutoff_version %d",
ntohs(h->cutoff_version));
if (h->retransmit)
used = homa_snprintf(buffer, buf_len, used,
", RETRANSMIT");
bytes_left = skb->len - sizeof32(*h) - seg_length;
if (skb_shinfo(skb)->gso_segs <= 1)
break;
used = homa_snprintf(buffer, buf_len, used, ", extra segs");
for (i = skb_shinfo(skb)->gso_segs - 1; i > 0; i--) {
seg = (struct data_segment *) (skb->data + skb->len
- bytes_left);
seg_length = ntohl(seg->segment_length);
used = homa_snprintf(buffer, buf_len, used,
" %d@%d", seg_length,
ntohl(seg->offset));
bytes_left -= sizeof32(*seg) + seg_length;
};
break;
}
case GRANT: {
struct grant_header *h = (struct grant_header *) skb->data;
used = homa_snprintf(buffer, buf_len, used,
", offset %d, grant_prio %u",
ntohl(h->offset), h->priority);
break;
}
case RESEND: {
struct resend_header *h = (struct resend_header *) skb->data;
used = homa_snprintf(buffer, buf_len, used,
", offset %d, length %d, resend_prio %u",
ntohl(h->offset), ntohl(h->length),
h->priority);
break;
}
case UNKNOWN:
/* Nothing to add here. */
break;
case BUSY:
/* Nothing to add here. */
break;
case CUTOFFS: {
struct cutoffs_header *h = (struct cutoffs_header *) skb->data;
used = homa_snprintf(buffer, buf_len, used,
", cutoffs %d %d %d %d %d %d %d %d, version %u",
ntohl(h->unsched_cutoffs[0]),
ntohl(h->unsched_cutoffs[1]),
ntohl(h->unsched_cutoffs[2]),
ntohl(h->unsched_cutoffs[3]),
ntohl(h->unsched_cutoffs[4]),
ntohl(h->unsched_cutoffs[5]),
ntohl(h->unsched_cutoffs[6]),
ntohl(h->unsched_cutoffs[7]),
ntohs(h->cutoff_version));
break;
}
case FREEZE:
/* Nothing to add here. */
break;
}
buffer[buf_len-1] = 0;
return buffer;
}
/**
* homa_print_packet_short() - Print a human-readable string describing the
* information in a Homa packet. This function generates a shorter
* description than homa_print_packet.
* @skb: Packet whose information should be printed.
* @buffer: Buffer in which to generate the string.
* @buf_len: Number of bytes available at @buffer.
*
* Return: @buffer
*/
char *homa_print_packet_short(struct sk_buff *skb, char *buffer, int buf_len)
{
struct common_header *common =
(struct common_header *) skb_transport_header(skb);
switch (common->type) {
case DATA: {
struct data_header *h = (struct data_header *) common;
struct data_segment *seg;
int bytes_left, used, i;
int seg_length = ntohl(h->seg.segment_length);
used = homa_snprintf(buffer, buf_len, 0, "DATA%s %d@%d",
h->retransmit ? " retrans" : "",
seg_length, ntohl(h->seg.offset));
bytes_left = skb->len - sizeof32(*h) - seg_length;
for (i = skb_shinfo(skb)->gso_segs - 1; i > 0; i--) {
seg = (struct data_segment *) (skb->data + skb->len
- bytes_left);
seg_length = ntohl(seg->segment_length);
used = homa_snprintf(buffer, buf_len, used,
" %d@%d", seg_length,
ntohl(seg->offset));
bytes_left -= sizeof32(*seg) + seg_length;
}
break;
}
case GRANT: {
struct grant_header *h = (struct grant_header *) common;
snprintf(buffer, buf_len, "GRANT %d@%d", ntohl(h->offset),
h->priority);
break;
}
case RESEND: {
struct resend_header *h = (struct resend_header *) common;
snprintf(buffer, buf_len, "RESEND %d-%d@%d", ntohl(h->offset),
ntohl(h->offset) + ntohl(h->length) - 1,
h->priority);
break;
}
case UNKNOWN:
snprintf(buffer, buf_len, "UNKNOWN");
break;
case BUSY:
snprintf(buffer, buf_len, "BUSY");
break;
case CUTOFFS:
snprintf(buffer, buf_len, "CUTOFFS");
break;
case FREEZE:
snprintf(buffer, buf_len, "FREEZE");
break;
default:
snprintf(buffer, buf_len, "unknown packet type %d",
common->type);
break;
}
return buffer;
}
/**
* homa_snprintf() - This function makes it easy to use a series of calls
* to snprintf to gradually append information to a fixed-size buffer.
* If the buffer fills, the function can continue to be called, but nothing
* more will get added to the buffer.
* @buffer: Characters accumulate here.
* @size: Total space available in @buffer.
* @used: Number of bytes currently occupied in the buffer, not including
* a terminating null character; this is typically the result of
* the previous call to this function.
* @format: Format string suitable for passing to printf-like functions,
* followed by values for the various substitutions requested
* in @format
* @ ...
*
* Return: The number of characters now occupied in @buffer, not
* including the terminating null character.
*/
int homa_snprintf(char *buffer, int size, int used, const char* format, ...)
{
int new_chars;
va_list ap;
va_start(ap, format);
if (used >= (size-1))
return used;
new_chars = vsnprintf(buffer + used, size - used, format, ap);
if (new_chars < 0)
return used;
if (new_chars >= (size - used))
return size - 1;
return used + new_chars;
}
/**
* homa_symbol_for_state() - Returns a printable string describing an
* RPC state.
* @rpc: RPC whose state should be returned in printable form.
*
* Return: A static string holding the current state of @rpc.
*/
char *homa_symbol_for_state(struct homa_rpc *rpc)
{
static char buffer[20];
switch (rpc->state) {
case RPC_OUTGOING:
return "OUTGOING";
case RPC_INCOMING:
return "INCOMING";
case RPC_READY:
return "READY";
case RPC_IN_SERVICE:
return "IN_SERVICE";
case RPC_DEAD:
return "DEAD";
}
/* See safety comment in homa_symbol_for_type. */
snprintf(buffer, sizeof(buffer)-1, "UNKNOWN(%u)", rpc->state);
buffer[sizeof(buffer)-1] = 0;
return buffer;
}
/**
* homa_symbol_for_type() - Returns a printable string describing a packet type.
* @type: A value from those defined by &homa_packet_type.
*
* Return: A static string holding the packet type corresponding to @type.
*/
char *homa_symbol_for_type(uint8_t type)
{
static char buffer[20];
switch (type) {
case DATA:
return "DATA";
case GRANT:
return "GRANT";
case RESEND:
return "RESEND";
case UNKNOWN:
return "UNKNOWN";
case BUSY:
return "BUSY";
case CUTOFFS:
return "CUTOFFS";
case FREEZE:
return "FREEZE";
}
/* Using a static buffer can produce garbled text under concurrency,
* but (a) it's unlikely (this code only executes if the opcode is
* bogus), (b) this is mostly for testing and debugging, and (c) the
* code below ensures that the string cannot run past the end of the
* buffer, so the code is safe. */
snprintf(buffer, sizeof(buffer)-1, "UNKNOWN(%u)", type);
buffer[sizeof(buffer)-1] = 0;
return buffer;
}
/**
* homa_append_metric() - Formats a new metric and appends it to homa->metrics.
* @homa: The new data will appended to the @metrics field of
* this structure.
* @format: Standard printf-style format string describing the
* new metric. Arguments after this provide the usual
* values expected for printf-like functions.
*/
void homa_append_metric(struct homa *homa, const char* format, ...)
{
char *new_buffer;
size_t new_chars;
va_list ap;
if (!homa->metrics) {
#ifdef __UNIT_TEST__
homa->metrics_capacity = 30;
#else
homa->metrics_capacity = 4096;
#endif
homa->metrics = kmalloc(homa->metrics_capacity, GFP_KERNEL);
if (!homa->metrics) {
printk(KERN_WARNING "homa_append_metric couldn't "
"allocate memory\n");
return;
}
homa->metrics_length = 0;
}
/* May have to execute this loop multiple times if we run out
* of space in homa->metrics; each iteration expands the storage,
* until eventually it is large enough.
*/
while (true) {
va_start(ap, format);
new_chars = vsnprintf(homa->metrics + homa->metrics_length,
homa->metrics_capacity - homa->metrics_length,
format, ap);
va_end(ap);
if ((homa->metrics_length + new_chars) < homa->metrics_capacity)
break;
/* Not enough room; expand buffer capacity. */
homa->metrics_capacity *= 2;
new_buffer = kmalloc(homa->metrics_capacity, GFP_KERNEL);
if (!new_buffer) {
printk(KERN_WARNING "homa_append_metric couldn't "
"allocate memory\n");
return;
}
memcpy(new_buffer, homa->metrics, homa->metrics_length);
kfree(homa->metrics);
homa->metrics = new_buffer;
}
homa->metrics_length += new_chars;
}
/**
* homa_print_metrics() - Sample all of the Homa performance metrics and
* generate a human-readable string describing all of them.
* @homa: Overall data about the Homa protocol implementation;
* the formatted string will be stored in homa->metrics.
*
* Return: The formatted string.
*/
char *homa_print_metrics(struct homa *homa)
{
int core, i, lower = 0;