The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/net/netisr.c

Version: -  FREEBSD  -  FREEBSD-13-STABLE  -  FREEBSD-13-0  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  l41  -  OPENBSD  -  linux-2.6  -  MK84  -  PLAN9  -  xnu-8792 
SearchContext: -  none  -  3  -  10 

    1 /*-
    2  * Copyright (c) 2007-2009 Robert N. M. Watson
    3  * Copyright (c) 2010-2011 Juniper Networks, Inc.
    4  * All rights reserved.
    5  *
    6  * This software was developed by Robert N. M. Watson under contract
    7  * to Juniper Networks, Inc.
    8  *
    9  * Redistribution and use in source and binary forms, with or without
   10  * modification, are permitted provided that the following conditions
   11  * are met:
   12  * 1. Redistributions of source code must retain the above copyright
   13  *    notice, this list of conditions and the following disclaimer.
   14  * 2. Redistributions in binary form must reproduce the above copyright
   15  *    notice, this list of conditions and the following disclaimer in the
   16  *    documentation and/or other materials provided with the distribution.
   17  *
   18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   28  * SUCH DAMAGE.
   29  */
   30 
   31 #include <sys/cdefs.h>
   32 __FBSDID("$FreeBSD: releng/10.3/sys/net/netisr.c 282832 2015-05-13 08:04:50Z hiren $");
   33 
   34 /*
   35  * netisr is a packet dispatch service, allowing synchronous (directly
   36  * dispatched) and asynchronous (deferred dispatch) processing of packets by
   37  * registered protocol handlers.  Callers pass a protocol identifier and
   38  * packet to netisr, along with a direct dispatch hint, and work will either
   39  * be immediately processed by the registered handler, or passed to a
   40  * software interrupt (SWI) thread for deferred dispatch.  Callers will
   41  * generally select one or the other based on:
   42  *
   43  * - Whether directly dispatching a netisr handler lead to code reentrance or
   44  *   lock recursion, such as entering the socket code from the socket code.
   45  * - Whether directly dispatching a netisr handler lead to recursive
   46  *   processing, such as when decapsulating several wrapped layers of tunnel
   47  *   information (IPSEC within IPSEC within ...).
   48  *
   49  * Maintaining ordering for protocol streams is a critical design concern.
   50  * Enforcing ordering limits the opportunity for concurrency, but maintains
   51  * the strong ordering requirements found in some protocols, such as TCP.  Of
   52  * related concern is CPU affinity--it is desirable to process all data
   53  * associated with a particular stream on the same CPU over time in order to
   54  * avoid acquiring locks associated with the connection on different CPUs,
   55  * keep connection data in one cache, and to generally encourage associated
   56  * user threads to live on the same CPU as the stream.  It's also desirable
   57  * to avoid lock migration and contention where locks are associated with
   58  * more than one flow.
   59  *
   60  * netisr supports several policy variations, represented by the
   61  * NETISR_POLICY_* constants, allowing protocols to play various roles in
   62  * identifying flows, assigning work to CPUs, etc.  These are described in
   63  * netisr.h.
   64  */
   65 
   66 #include "opt_ddb.h"
   67 #include "opt_device_polling.h"
   68 
   69 #include <sys/param.h>
   70 #include <sys/bus.h>
   71 #include <sys/kernel.h>
   72 #include <sys/kthread.h>
   73 #include <sys/interrupt.h>
   74 #include <sys/lock.h>
   75 #include <sys/mbuf.h>
   76 #include <sys/mutex.h>
   77 #include <sys/pcpu.h>
   78 #include <sys/proc.h>
   79 #include <sys/rmlock.h>
   80 #include <sys/sched.h>
   81 #include <sys/smp.h>
   82 #include <sys/socket.h>
   83 #include <sys/sysctl.h>
   84 #include <sys/systm.h>
   85 
   86 #ifdef DDB
   87 #include <ddb/ddb.h>
   88 #endif
   89 
   90 #define _WANT_NETISR_INTERNAL   /* Enable definitions from netisr_internal.h */
   91 #include <net/if.h>
   92 #include <net/if_var.h>
   93 #include <net/netisr.h>
   94 #include <net/netisr_internal.h>
   95 #include <net/vnet.h>
   96 
   97 /*-
   98  * Synchronize use and modification of the registered netisr data structures;
   99  * acquire a read lock while modifying the set of registered protocols to
  100  * prevent partially registered or unregistered protocols from being run.
  101  *
  102  * The following data structures and fields are protected by this lock:
  103  *
  104  * - The netisr_proto array, including all fields of struct netisr_proto.
  105  * - The nws array, including all fields of struct netisr_worker.
  106  * - The nws_array array.
  107  *
  108  * Note: the NETISR_LOCKING define controls whether read locks are acquired
  109  * in packet processing paths requiring netisr registration stability.  This
  110  * is disabled by default as it can lead to measurable performance
  111  * degradation even with rmlocks (3%-6% for loopback ping-pong traffic), and
  112  * because netisr registration and unregistration is extremely rare at
  113  * runtime.  If it becomes more common, this decision should be revisited.
  114  *
  115  * XXXRW: rmlocks don't support assertions.
  116  */
  117 static struct rmlock    netisr_rmlock;
  118 #define NETISR_LOCK_INIT()      rm_init_flags(&netisr_rmlock, "netisr", \
  119                                     RM_NOWITNESS)
  120 #define NETISR_LOCK_ASSERT()
  121 #define NETISR_RLOCK(tracker)   rm_rlock(&netisr_rmlock, (tracker))
  122 #define NETISR_RUNLOCK(tracker) rm_runlock(&netisr_rmlock, (tracker))
  123 #define NETISR_WLOCK()          rm_wlock(&netisr_rmlock)
  124 #define NETISR_WUNLOCK()        rm_wunlock(&netisr_rmlock)
  125 /* #define      NETISR_LOCKING */
  126 
  127 static SYSCTL_NODE(_net, OID_AUTO, isr, CTLFLAG_RW, 0, "netisr");
  128 
  129 /*-
  130  * Three global direct dispatch policies are supported:
  131  *
  132  * NETISR_DISPATCH_QUEUED: All work is deferred for a netisr, regardless of
  133  * context (may be overriden by protocols).
  134  *
  135  * NETISR_DISPATCH_HYBRID: If the executing context allows direct dispatch,
  136  * and we're running on the CPU the work would be performed on, then direct
  137  * dispatch it if it wouldn't violate ordering constraints on the workstream.
  138  *
  139  * NETISR_DISPATCH_DIRECT: If the executing context allows direct dispatch,
  140  * always direct dispatch.  (The default.)
  141  *
  142  * Notice that changing the global policy could lead to short periods of
  143  * misordered processing, but this is considered acceptable as compared to
  144  * the complexity of enforcing ordering during policy changes.  Protocols can
  145  * override the global policy (when they're not doing that, they select
  146  * NETISR_DISPATCH_DEFAULT).
  147  */
  148 #define NETISR_DISPATCH_POLICY_DEFAULT  NETISR_DISPATCH_DIRECT
  149 #define NETISR_DISPATCH_POLICY_MAXSTR   20 /* Used for temporary buffers. */
  150 static u_int    netisr_dispatch_policy = NETISR_DISPATCH_POLICY_DEFAULT;
  151 static int      sysctl_netisr_dispatch_policy(SYSCTL_HANDLER_ARGS);
  152 SYSCTL_PROC(_net_isr, OID_AUTO, dispatch, CTLTYPE_STRING | CTLFLAG_RW |
  153     CTLFLAG_TUN, 0, 0, sysctl_netisr_dispatch_policy, "A",
  154     "netisr dispatch policy");
  155 
  156 /*
  157  * Allow the administrator to limit the number of threads (CPUs) to use for
  158  * netisr.  We don't check netisr_maxthreads before creating the thread for
  159  * CPU 0. This must be set at boot. We will create at most one thread per CPU.
  160  * By default we initialize this to 1 which would assign just 1 cpu (cpu0) and
  161  * therefore only 1 workstream. If set to -1, netisr would use all cpus
  162  * (mp_ncpus) and therefore would have those many workstreams. One workstream
  163  * per thread (CPU).
  164  */
  165 static int      netisr_maxthreads = 1;          /* Max number of threads. */
  166 TUNABLE_INT("net.isr.maxthreads", &netisr_maxthreads);
  167 SYSCTL_INT(_net_isr, OID_AUTO, maxthreads, CTLFLAG_RDTUN,
  168     &netisr_maxthreads, 0,
  169     "Use at most this many CPUs for netisr processing");
  170 
  171 static int      netisr_bindthreads = 0;         /* Bind threads to CPUs. */
  172 TUNABLE_INT("net.isr.bindthreads", &netisr_bindthreads);
  173 SYSCTL_INT(_net_isr, OID_AUTO, bindthreads, CTLFLAG_RDTUN,
  174     &netisr_bindthreads, 0, "Bind netisr threads to CPUs.");
  175 
  176 /*
  177  * Limit per-workstream mbuf queue limits s to at most net.isr.maxqlimit,
  178  * both for initial configuration and later modification using
  179  * netisr_setqlimit().
  180  */
  181 #define NETISR_DEFAULT_MAXQLIMIT        10240
  182 static u_int    netisr_maxqlimit = NETISR_DEFAULT_MAXQLIMIT;
  183 TUNABLE_INT("net.isr.maxqlimit", &netisr_maxqlimit);
  184 SYSCTL_UINT(_net_isr, OID_AUTO, maxqlimit, CTLFLAG_RDTUN,
  185     &netisr_maxqlimit, 0,
  186     "Maximum netisr per-protocol, per-CPU queue depth.");
  187 
  188 /*
  189  * The default per-workstream mbuf queue limit for protocols that don't
  190  * initialize the nh_qlimit field of their struct netisr_handler.  If this is
  191  * set above netisr_maxqlimit, we truncate it to the maximum during boot.
  192  */
  193 #define NETISR_DEFAULT_DEFAULTQLIMIT    256
  194 static u_int    netisr_defaultqlimit = NETISR_DEFAULT_DEFAULTQLIMIT;
  195 TUNABLE_INT("net.isr.defaultqlimit", &netisr_defaultqlimit);
  196 SYSCTL_UINT(_net_isr, OID_AUTO, defaultqlimit, CTLFLAG_RDTUN,
  197     &netisr_defaultqlimit, 0,
  198     "Default netisr per-protocol, per-CPU queue limit if not set by protocol");
  199 
  200 /*
  201  * Store and export the compile-time constant NETISR_MAXPROT limit on the
  202  * number of protocols that can register with netisr at a time.  This is
  203  * required for crashdump analysis, as it sizes netisr_proto[].
  204  */
  205 static u_int    netisr_maxprot = NETISR_MAXPROT;
  206 SYSCTL_UINT(_net_isr, OID_AUTO, maxprot, CTLFLAG_RD,
  207     &netisr_maxprot, 0,
  208     "Compile-time limit on the number of protocols supported by netisr.");
  209 
  210 /*
  211  * The netisr_proto array describes all registered protocols, indexed by
  212  * protocol number.  See netisr_internal.h for more details.
  213  */
  214 static struct netisr_proto      netisr_proto[NETISR_MAXPROT];
  215 
  216 /*
  217  * Per-CPU workstream data.  See netisr_internal.h for more details.
  218  */
  219 DPCPU_DEFINE(struct netisr_workstream, nws);
  220 
  221 /*
  222  * Map contiguous values between 0 and nws_count into CPU IDs appropriate for
  223  * accessing workstreams.  This allows constructions of the form
  224  * DPCPU_ID_GET(nws_array[arbitraryvalue % nws_count], nws).
  225  */
  226 static u_int                             nws_array[MAXCPU];
  227 
  228 /*
  229  * Number of registered workstreams.  Will be at most the number of running
  230  * CPUs once fully started.
  231  */
  232 static u_int                             nws_count;
  233 SYSCTL_UINT(_net_isr, OID_AUTO, numthreads, CTLFLAG_RD,
  234     &nws_count, 0, "Number of extant netisr threads.");
  235 
  236 /*
  237  * Synchronization for each workstream: a mutex protects all mutable fields
  238  * in each stream, including per-protocol state (mbuf queues).  The SWI is
  239  * woken up if asynchronous dispatch is required.
  240  */
  241 #define NWS_LOCK(s)             mtx_lock(&(s)->nws_mtx)
  242 #define NWS_LOCK_ASSERT(s)      mtx_assert(&(s)->nws_mtx, MA_OWNED)
  243 #define NWS_UNLOCK(s)           mtx_unlock(&(s)->nws_mtx)
  244 #define NWS_SIGNAL(s)           swi_sched((s)->nws_swi_cookie, 0)
  245 
  246 /*
  247  * Utility routines for protocols that implement their own mapping of flows
  248  * to CPUs.
  249  */
  250 u_int
  251 netisr_get_cpucount(void)
  252 {
  253 
  254         return (nws_count);
  255 }
  256 
  257 u_int
  258 netisr_get_cpuid(u_int cpunumber)
  259 {
  260 
  261         KASSERT(cpunumber < nws_count, ("%s: %u > %u", __func__, cpunumber,
  262             nws_count));
  263 
  264         return (nws_array[cpunumber]);
  265 }
  266 
  267 /*
  268  * The default implementation of flow -> CPU ID mapping.
  269  *
  270  * Non-static so that protocols can use it to map their own work to specific
  271  * CPUs in a manner consistent to netisr for affinity purposes.
  272  */
  273 u_int
  274 netisr_default_flow2cpu(u_int flowid)
  275 {
  276 
  277         return (nws_array[flowid % nws_count]);
  278 }
  279 
  280 /*
  281  * Dispatch tunable and sysctl configuration.
  282  */
  283 struct netisr_dispatch_table_entry {
  284         u_int            ndte_policy;
  285         const char      *ndte_policy_str;
  286 };
  287 static const struct netisr_dispatch_table_entry netisr_dispatch_table[] = {
  288         { NETISR_DISPATCH_DEFAULT, "default" },
  289         { NETISR_DISPATCH_DEFERRED, "deferred" },
  290         { NETISR_DISPATCH_HYBRID, "hybrid" },
  291         { NETISR_DISPATCH_DIRECT, "direct" },
  292 };
  293 static const u_int netisr_dispatch_table_len =
  294     (sizeof(netisr_dispatch_table) / sizeof(netisr_dispatch_table[0]));
  295 
  296 static void
  297 netisr_dispatch_policy_to_str(u_int dispatch_policy, char *buffer,
  298     u_int buflen)
  299 {
  300         const struct netisr_dispatch_table_entry *ndtep;
  301         const char *str;
  302         u_int i;
  303 
  304         str = "unknown";
  305         for (i = 0; i < netisr_dispatch_table_len; i++) {
  306                 ndtep = &netisr_dispatch_table[i];
  307                 if (ndtep->ndte_policy == dispatch_policy) {
  308                         str = ndtep->ndte_policy_str;
  309                         break;
  310                 }
  311         }
  312         snprintf(buffer, buflen, "%s", str);
  313 }
  314 
  315 static int
  316 netisr_dispatch_policy_from_str(const char *str, u_int *dispatch_policyp)
  317 {
  318         const struct netisr_dispatch_table_entry *ndtep;
  319         u_int i;
  320 
  321         for (i = 0; i < netisr_dispatch_table_len; i++) {
  322                 ndtep = &netisr_dispatch_table[i];
  323                 if (strcmp(ndtep->ndte_policy_str, str) == 0) {
  324                         *dispatch_policyp = ndtep->ndte_policy;
  325                         return (0);
  326                 }
  327         }
  328         return (EINVAL);
  329 }
  330 
  331 static int
  332 sysctl_netisr_dispatch_policy(SYSCTL_HANDLER_ARGS)
  333 {
  334         char tmp[NETISR_DISPATCH_POLICY_MAXSTR];
  335         u_int dispatch_policy;
  336         int error;
  337 
  338         netisr_dispatch_policy_to_str(netisr_dispatch_policy, tmp,
  339             sizeof(tmp));
  340         error = sysctl_handle_string(oidp, tmp, sizeof(tmp), req);
  341         if (error == 0 && req->newptr != NULL) {
  342                 error = netisr_dispatch_policy_from_str(tmp,
  343                     &dispatch_policy);
  344                 if (error == 0 && dispatch_policy == NETISR_DISPATCH_DEFAULT)
  345                         error = EINVAL;
  346                 if (error == 0)
  347                         netisr_dispatch_policy = dispatch_policy;
  348         }
  349         return (error);
  350 }
  351 
  352 /*
  353  * Register a new netisr handler, which requires initializing per-protocol
  354  * fields for each workstream.  All netisr work is briefly suspended while
  355  * the protocol is installed.
  356  */
  357 void
  358 netisr_register(const struct netisr_handler *nhp)
  359 {
  360         struct netisr_work *npwp;
  361         const char *name;
  362         u_int i, proto;
  363 
  364         proto = nhp->nh_proto;
  365         name = nhp->nh_name;
  366 
  367         /*
  368          * Test that the requested registration is valid.
  369          */
  370         KASSERT(nhp->nh_name != NULL,
  371             ("%s: nh_name NULL for %u", __func__, proto));
  372         KASSERT(nhp->nh_handler != NULL,
  373             ("%s: nh_handler NULL for %s", __func__, name));
  374         KASSERT(nhp->nh_policy == NETISR_POLICY_SOURCE ||
  375             nhp->nh_policy == NETISR_POLICY_FLOW ||
  376             nhp->nh_policy == NETISR_POLICY_CPU,
  377             ("%s: unsupported nh_policy %u for %s", __func__,
  378             nhp->nh_policy, name));
  379         KASSERT(nhp->nh_policy == NETISR_POLICY_FLOW ||
  380             nhp->nh_m2flow == NULL,
  381             ("%s: nh_policy != FLOW but m2flow defined for %s", __func__,
  382             name));
  383         KASSERT(nhp->nh_policy == NETISR_POLICY_CPU || nhp->nh_m2cpuid == NULL,
  384             ("%s: nh_policy != CPU but m2cpuid defined for %s", __func__,
  385             name));
  386         KASSERT(nhp->nh_policy != NETISR_POLICY_CPU || nhp->nh_m2cpuid != NULL,
  387             ("%s: nh_policy == CPU but m2cpuid not defined for %s", __func__,
  388             name));
  389         KASSERT(nhp->nh_dispatch == NETISR_DISPATCH_DEFAULT ||
  390             nhp->nh_dispatch == NETISR_DISPATCH_DEFERRED ||
  391             nhp->nh_dispatch == NETISR_DISPATCH_HYBRID ||
  392             nhp->nh_dispatch == NETISR_DISPATCH_DIRECT,
  393             ("%s: invalid nh_dispatch (%u)", __func__, nhp->nh_dispatch));
  394 
  395         KASSERT(proto < NETISR_MAXPROT,
  396             ("%s(%u, %s): protocol too big", __func__, proto, name));
  397 
  398         /*
  399          * Test that no existing registration exists for this protocol.
  400          */
  401         NETISR_WLOCK();
  402         KASSERT(netisr_proto[proto].np_name == NULL,
  403             ("%s(%u, %s): name present", __func__, proto, name));
  404         KASSERT(netisr_proto[proto].np_handler == NULL,
  405             ("%s(%u, %s): handler present", __func__, proto, name));
  406 
  407         netisr_proto[proto].np_name = name;
  408         netisr_proto[proto].np_handler = nhp->nh_handler;
  409         netisr_proto[proto].np_m2flow = nhp->nh_m2flow;
  410         netisr_proto[proto].np_m2cpuid = nhp->nh_m2cpuid;
  411         netisr_proto[proto].np_drainedcpu = nhp->nh_drainedcpu;
  412         if (nhp->nh_qlimit == 0)
  413                 netisr_proto[proto].np_qlimit = netisr_defaultqlimit;
  414         else if (nhp->nh_qlimit > netisr_maxqlimit) {
  415                 printf("%s: %s requested queue limit %u capped to "
  416                     "net.isr.maxqlimit %u\n", __func__, name, nhp->nh_qlimit,
  417                     netisr_maxqlimit);
  418                 netisr_proto[proto].np_qlimit = netisr_maxqlimit;
  419         } else
  420                 netisr_proto[proto].np_qlimit = nhp->nh_qlimit;
  421         netisr_proto[proto].np_policy = nhp->nh_policy;
  422         netisr_proto[proto].np_dispatch = nhp->nh_dispatch;
  423         CPU_FOREACH(i) {
  424                 npwp = &(DPCPU_ID_PTR(i, nws))->nws_work[proto];
  425                 bzero(npwp, sizeof(*npwp));
  426                 npwp->nw_qlimit = netisr_proto[proto].np_qlimit;
  427         }
  428         NETISR_WUNLOCK();
  429 }
  430 
  431 /*
  432  * Clear drop counters across all workstreams for a protocol.
  433  */
  434 void
  435 netisr_clearqdrops(const struct netisr_handler *nhp)
  436 {
  437         struct netisr_work *npwp;
  438 #ifdef INVARIANTS
  439         const char *name;
  440 #endif
  441         u_int i, proto;
  442 
  443         proto = nhp->nh_proto;
  444 #ifdef INVARIANTS
  445         name = nhp->nh_name;
  446 #endif
  447         KASSERT(proto < NETISR_MAXPROT,
  448             ("%s(%u): protocol too big for %s", __func__, proto, name));
  449 
  450         NETISR_WLOCK();
  451         KASSERT(netisr_proto[proto].np_handler != NULL,
  452             ("%s(%u): protocol not registered for %s", __func__, proto,
  453             name));
  454 
  455         CPU_FOREACH(i) {
  456                 npwp = &(DPCPU_ID_PTR(i, nws))->nws_work[proto];
  457                 npwp->nw_qdrops = 0;
  458         }
  459         NETISR_WUNLOCK();
  460 }
  461 
  462 /*
  463  * Query current drop counters across all workstreams for a protocol.
  464  */
  465 void
  466 netisr_getqdrops(const struct netisr_handler *nhp, u_int64_t *qdropp)
  467 {
  468         struct netisr_work *npwp;
  469         struct rm_priotracker tracker;
  470 #ifdef INVARIANTS
  471         const char *name;
  472 #endif
  473         u_int i, proto;
  474 
  475         *qdropp = 0;
  476         proto = nhp->nh_proto;
  477 #ifdef INVARIANTS
  478         name = nhp->nh_name;
  479 #endif
  480         KASSERT(proto < NETISR_MAXPROT,
  481             ("%s(%u): protocol too big for %s", __func__, proto, name));
  482 
  483         NETISR_RLOCK(&tracker);
  484         KASSERT(netisr_proto[proto].np_handler != NULL,
  485             ("%s(%u): protocol not registered for %s", __func__, proto,
  486             name));
  487 
  488         CPU_FOREACH(i) {
  489                 npwp = &(DPCPU_ID_PTR(i, nws))->nws_work[proto];
  490                 *qdropp += npwp->nw_qdrops;
  491         }
  492         NETISR_RUNLOCK(&tracker);
  493 }
  494 
  495 /*
  496  * Query current per-workstream queue limit for a protocol.
  497  */
  498 void
  499 netisr_getqlimit(const struct netisr_handler *nhp, u_int *qlimitp)
  500 {
  501         struct rm_priotracker tracker;
  502 #ifdef INVARIANTS
  503         const char *name;
  504 #endif
  505         u_int proto;
  506 
  507         proto = nhp->nh_proto;
  508 #ifdef INVARIANTS
  509         name = nhp->nh_name;
  510 #endif
  511         KASSERT(proto < NETISR_MAXPROT,
  512             ("%s(%u): protocol too big for %s", __func__, proto, name));
  513 
  514         NETISR_RLOCK(&tracker);
  515         KASSERT(netisr_proto[proto].np_handler != NULL,
  516             ("%s(%u): protocol not registered for %s", __func__, proto,
  517             name));
  518         *qlimitp = netisr_proto[proto].np_qlimit;
  519         NETISR_RUNLOCK(&tracker);
  520 }
  521 
  522 /*
  523  * Update the queue limit across per-workstream queues for a protocol.  We
  524  * simply change the limits, and don't drain overflowed packets as they will
  525  * (hopefully) take care of themselves shortly.
  526  */
  527 int
  528 netisr_setqlimit(const struct netisr_handler *nhp, u_int qlimit)
  529 {
  530         struct netisr_work *npwp;
  531 #ifdef INVARIANTS
  532         const char *name;
  533 #endif
  534         u_int i, proto;
  535 
  536         if (qlimit > netisr_maxqlimit)
  537                 return (EINVAL);
  538 
  539         proto = nhp->nh_proto;
  540 #ifdef INVARIANTS
  541         name = nhp->nh_name;
  542 #endif
  543         KASSERT(proto < NETISR_MAXPROT,
  544             ("%s(%u): protocol too big for %s", __func__, proto, name));
  545 
  546         NETISR_WLOCK();
  547         KASSERT(netisr_proto[proto].np_handler != NULL,
  548             ("%s(%u): protocol not registered for %s", __func__, proto,
  549             name));
  550 
  551         netisr_proto[proto].np_qlimit = qlimit;
  552         CPU_FOREACH(i) {
  553                 npwp = &(DPCPU_ID_PTR(i, nws))->nws_work[proto];
  554                 npwp->nw_qlimit = qlimit;
  555         }
  556         NETISR_WUNLOCK();
  557         return (0);
  558 }
  559 
  560 /*
  561  * Drain all packets currently held in a particular protocol work queue.
  562  */
  563 static void
  564 netisr_drain_proto(struct netisr_work *npwp)
  565 {
  566         struct mbuf *m;
  567 
  568         /*
  569          * We would assert the lock on the workstream but it's not passed in.
  570          */
  571         while ((m = npwp->nw_head) != NULL) {
  572                 npwp->nw_head = m->m_nextpkt;
  573                 m->m_nextpkt = NULL;
  574                 if (npwp->nw_head == NULL)
  575                         npwp->nw_tail = NULL;
  576                 npwp->nw_len--;
  577                 m_freem(m);
  578         }
  579         KASSERT(npwp->nw_tail == NULL, ("%s: tail", __func__));
  580         KASSERT(npwp->nw_len == 0, ("%s: len", __func__));
  581 }
  582 
  583 /*
  584  * Remove the registration of a network protocol, which requires clearing
  585  * per-protocol fields across all workstreams, including freeing all mbufs in
  586  * the queues at time of unregister.  All work in netisr is briefly suspended
  587  * while this takes place.
  588  */
  589 void
  590 netisr_unregister(const struct netisr_handler *nhp)
  591 {
  592         struct netisr_work *npwp;
  593 #ifdef INVARIANTS
  594         const char *name;
  595 #endif
  596         u_int i, proto;
  597 
  598         proto = nhp->nh_proto;
  599 #ifdef INVARIANTS
  600         name = nhp->nh_name;
  601 #endif
  602         KASSERT(proto < NETISR_MAXPROT,
  603             ("%s(%u): protocol too big for %s", __func__, proto, name));
  604 
  605         NETISR_WLOCK();
  606         KASSERT(netisr_proto[proto].np_handler != NULL,
  607             ("%s(%u): protocol not registered for %s", __func__, proto,
  608             name));
  609 
  610         netisr_proto[proto].np_name = NULL;
  611         netisr_proto[proto].np_handler = NULL;
  612         netisr_proto[proto].np_m2flow = NULL;
  613         netisr_proto[proto].np_m2cpuid = NULL;
  614         netisr_proto[proto].np_qlimit = 0;
  615         netisr_proto[proto].np_policy = 0;
  616         CPU_FOREACH(i) {
  617                 npwp = &(DPCPU_ID_PTR(i, nws))->nws_work[proto];
  618                 netisr_drain_proto(npwp);
  619                 bzero(npwp, sizeof(*npwp));
  620         }
  621         NETISR_WUNLOCK();
  622 }
  623 
  624 /*
  625  * Compose the global and per-protocol policies on dispatch, and return the
  626  * dispatch policy to use.
  627  */
  628 static u_int
  629 netisr_get_dispatch(struct netisr_proto *npp)
  630 {
  631 
  632         /*
  633          * Protocol-specific configuration overrides the global default.
  634          */
  635         if (npp->np_dispatch != NETISR_DISPATCH_DEFAULT)
  636                 return (npp->np_dispatch);
  637         return (netisr_dispatch_policy);
  638 }
  639 
  640 /*
  641  * Look up the workstream given a packet and source identifier.  Do this by
  642  * checking the protocol's policy, and optionally call out to the protocol
  643  * for assistance if required.
  644  */
  645 static struct mbuf *
  646 netisr_select_cpuid(struct netisr_proto *npp, u_int dispatch_policy,
  647     uintptr_t source, struct mbuf *m, u_int *cpuidp)
  648 {
  649         struct ifnet *ifp;
  650         u_int policy;
  651 
  652         NETISR_LOCK_ASSERT();
  653 
  654         /*
  655          * In the event we have only one worker, shortcut and deliver to it
  656          * without further ado.
  657          */
  658         if (nws_count == 1) {
  659                 *cpuidp = nws_array[0];
  660                 return (m);
  661         }
  662 
  663         /*
  664          * What happens next depends on the policy selected by the protocol.
  665          * If we want to support per-interface policies, we should do that
  666          * here first.
  667          */
  668         policy = npp->np_policy;
  669         if (policy == NETISR_POLICY_CPU) {
  670                 m = npp->np_m2cpuid(m, source, cpuidp);
  671                 if (m == NULL)
  672                         return (NULL);
  673 
  674                 /*
  675                  * It's possible for a protocol not to have a good idea about
  676                  * where to process a packet, in which case we fall back on
  677                  * the netisr code to decide.  In the hybrid case, return the
  678                  * current CPU ID, which will force an immediate direct
  679                  * dispatch.  In the queued case, fall back on the SOURCE
  680                  * policy.
  681                  */
  682                 if (*cpuidp != NETISR_CPUID_NONE)
  683                         return (m);
  684                 if (dispatch_policy == NETISR_DISPATCH_HYBRID) {
  685                         *cpuidp = curcpu;
  686                         return (m);
  687                 }
  688                 policy = NETISR_POLICY_SOURCE;
  689         }
  690 
  691         if (policy == NETISR_POLICY_FLOW) {
  692                 if (M_HASHTYPE_GET(m) == M_HASHTYPE_NONE &&
  693                     npp->np_m2flow != NULL) {
  694                         m = npp->np_m2flow(m, source);
  695                         if (m == NULL)
  696                                 return (NULL);
  697                 }
  698                 if (M_HASHTYPE_GET(m) != M_HASHTYPE_NONE) {
  699                         *cpuidp =
  700                             netisr_default_flow2cpu(m->m_pkthdr.flowid);
  701                         return (m);
  702                 }
  703                 policy = NETISR_POLICY_SOURCE;
  704         }
  705 
  706         KASSERT(policy == NETISR_POLICY_SOURCE,
  707             ("%s: invalid policy %u for %s", __func__, npp->np_policy,
  708             npp->np_name));
  709 
  710         ifp = m->m_pkthdr.rcvif;
  711         if (ifp != NULL)
  712                 *cpuidp = nws_array[(ifp->if_index + source) % nws_count];
  713         else
  714                 *cpuidp = nws_array[source % nws_count];
  715         return (m);
  716 }
  717 
  718 /*
  719  * Process packets associated with a workstream and protocol.  For reasons of
  720  * fairness, we process up to one complete netisr queue at a time, moving the
  721  * queue to a stack-local queue for processing, but do not loop refreshing
  722  * from the global queue.  The caller is responsible for deciding whether to
  723  * loop, and for setting the NWS_RUNNING flag.  The passed workstream will be
  724  * locked on entry and relocked before return, but will be released while
  725  * processing.  The number of packets processed is returned.
  726  */
  727 static u_int
  728 netisr_process_workstream_proto(struct netisr_workstream *nwsp, u_int proto)
  729 {
  730         struct netisr_work local_npw, *npwp;
  731         u_int handled;
  732         struct mbuf *m;
  733 
  734         NETISR_LOCK_ASSERT();
  735         NWS_LOCK_ASSERT(nwsp);
  736 
  737         KASSERT(nwsp->nws_flags & NWS_RUNNING,
  738             ("%s(%u): not running", __func__, proto));
  739         KASSERT(proto >= 0 && proto < NETISR_MAXPROT,
  740             ("%s(%u): invalid proto\n", __func__, proto));
  741 
  742         npwp = &nwsp->nws_work[proto];
  743         if (npwp->nw_len == 0)
  744                 return (0);
  745 
  746         /*
  747          * Move the global work queue to a thread-local work queue.
  748          *
  749          * Notice that this means the effective maximum length of the queue
  750          * is actually twice that of the maximum queue length specified in
  751          * the protocol registration call.
  752          */
  753         handled = npwp->nw_len;
  754         local_npw = *npwp;
  755         npwp->nw_head = NULL;
  756         npwp->nw_tail = NULL;
  757         npwp->nw_len = 0;
  758         nwsp->nws_pendingbits &= ~(1 << proto);
  759         NWS_UNLOCK(nwsp);
  760         while ((m = local_npw.nw_head) != NULL) {
  761                 local_npw.nw_head = m->m_nextpkt;
  762                 m->m_nextpkt = NULL;
  763                 if (local_npw.nw_head == NULL)
  764                         local_npw.nw_tail = NULL;
  765                 local_npw.nw_len--;
  766                 VNET_ASSERT(m->m_pkthdr.rcvif != NULL,
  767                     ("%s:%d rcvif == NULL: m=%p", __func__, __LINE__, m));
  768                 CURVNET_SET(m->m_pkthdr.rcvif->if_vnet);
  769                 netisr_proto[proto].np_handler(m);
  770                 CURVNET_RESTORE();
  771         }
  772         KASSERT(local_npw.nw_len == 0,
  773             ("%s(%u): len %u", __func__, proto, local_npw.nw_len));
  774         if (netisr_proto[proto].np_drainedcpu)
  775                 netisr_proto[proto].np_drainedcpu(nwsp->nws_cpu);
  776         NWS_LOCK(nwsp);
  777         npwp->nw_handled += handled;
  778         return (handled);
  779 }
  780 
  781 /*
  782  * SWI handler for netisr -- processes packets in a set of workstreams that
  783  * it owns, woken up by calls to NWS_SIGNAL().  If this workstream is already
  784  * being direct dispatched, go back to sleep and wait for the dispatching
  785  * thread to wake us up again.
  786  */
  787 static void
  788 swi_net(void *arg)
  789 {
  790 #ifdef NETISR_LOCKING
  791         struct rm_priotracker tracker;
  792 #endif
  793         struct netisr_workstream *nwsp;
  794         u_int bits, prot;
  795 
  796         nwsp = arg;
  797 
  798 #ifdef DEVICE_POLLING
  799         KASSERT(nws_count == 1,
  800             ("%s: device_polling but nws_count != 1", __func__));
  801         netisr_poll();
  802 #endif
  803 #ifdef NETISR_LOCKING
  804         NETISR_RLOCK(&tracker);
  805 #endif
  806         NWS_LOCK(nwsp);
  807         KASSERT(!(nwsp->nws_flags & NWS_RUNNING), ("swi_net: running"));
  808         if (nwsp->nws_flags & NWS_DISPATCHING)
  809                 goto out;
  810         nwsp->nws_flags |= NWS_RUNNING;
  811         nwsp->nws_flags &= ~NWS_SCHEDULED;
  812         while ((bits = nwsp->nws_pendingbits) != 0) {
  813                 while ((prot = ffs(bits)) != 0) {
  814                         prot--;
  815                         bits &= ~(1 << prot);
  816                         (void)netisr_process_workstream_proto(nwsp, prot);
  817                 }
  818         }
  819         nwsp->nws_flags &= ~NWS_RUNNING;
  820 out:
  821         NWS_UNLOCK(nwsp);
  822 #ifdef NETISR_LOCKING
  823         NETISR_RUNLOCK(&tracker);
  824 #endif
  825 #ifdef DEVICE_POLLING
  826         netisr_pollmore();
  827 #endif
  828 }
  829 
  830 static int
  831 netisr_queue_workstream(struct netisr_workstream *nwsp, u_int proto,
  832     struct netisr_work *npwp, struct mbuf *m, int *dosignalp)
  833 {
  834 
  835         NWS_LOCK_ASSERT(nwsp);
  836 
  837         *dosignalp = 0;
  838         if (npwp->nw_len < npwp->nw_qlimit) {
  839                 m->m_nextpkt = NULL;
  840                 if (npwp->nw_head == NULL) {
  841                         npwp->nw_head = m;
  842                         npwp->nw_tail = m;
  843                 } else {
  844                         npwp->nw_tail->m_nextpkt = m;
  845                         npwp->nw_tail = m;
  846                 }
  847                 npwp->nw_len++;
  848                 if (npwp->nw_len > npwp->nw_watermark)
  849                         npwp->nw_watermark = npwp->nw_len;
  850 
  851                 /*
  852                  * We must set the bit regardless of NWS_RUNNING, so that
  853                  * swi_net() keeps calling netisr_process_workstream_proto().
  854                  */
  855                 nwsp->nws_pendingbits |= (1 << proto);
  856                 if (!(nwsp->nws_flags & 
  857                     (NWS_RUNNING | NWS_DISPATCHING | NWS_SCHEDULED))) {
  858                         nwsp->nws_flags |= NWS_SCHEDULED;
  859                         *dosignalp = 1; /* Defer until unlocked. */
  860                 }
  861                 npwp->nw_queued++;
  862                 return (0);
  863         } else {
  864                 m_freem(m);
  865                 npwp->nw_qdrops++;
  866                 return (ENOBUFS);
  867         }
  868 }
  869 
  870 static int
  871 netisr_queue_internal(u_int proto, struct mbuf *m, u_int cpuid)
  872 {
  873         struct netisr_workstream *nwsp;
  874         struct netisr_work *npwp;
  875         int dosignal, error;
  876 
  877 #ifdef NETISR_LOCKING
  878         NETISR_LOCK_ASSERT();
  879 #endif
  880         KASSERT(cpuid <= mp_maxid, ("%s: cpuid too big (%u, %u)", __func__,
  881             cpuid, mp_maxid));
  882         KASSERT(!CPU_ABSENT(cpuid), ("%s: CPU %u absent", __func__, cpuid));
  883 
  884         dosignal = 0;
  885         error = 0;
  886         nwsp = DPCPU_ID_PTR(cpuid, nws);
  887         npwp = &nwsp->nws_work[proto];
  888         NWS_LOCK(nwsp);
  889         error = netisr_queue_workstream(nwsp, proto, npwp, m, &dosignal);
  890         NWS_UNLOCK(nwsp);
  891         if (dosignal)
  892                 NWS_SIGNAL(nwsp);
  893         return (error);
  894 }
  895 
  896 int
  897 netisr_queue_src(u_int proto, uintptr_t source, struct mbuf *m)
  898 {
  899 #ifdef NETISR_LOCKING
  900         struct rm_priotracker tracker;
  901 #endif
  902         u_int cpuid;
  903         int error;
  904 
  905         KASSERT(proto < NETISR_MAXPROT,
  906             ("%s: invalid proto %u", __func__, proto));
  907 
  908 #ifdef NETISR_LOCKING
  909         NETISR_RLOCK(&tracker);
  910 #endif
  911         KASSERT(netisr_proto[proto].np_handler != NULL,
  912             ("%s: invalid proto %u", __func__, proto));
  913 
  914         m = netisr_select_cpuid(&netisr_proto[proto], NETISR_DISPATCH_DEFERRED,
  915             source, m, &cpuid);
  916         if (m != NULL) {
  917                 KASSERT(!CPU_ABSENT(cpuid), ("%s: CPU %u absent", __func__,
  918                     cpuid));
  919                 error = netisr_queue_internal(proto, m, cpuid);
  920         } else
  921                 error = ENOBUFS;
  922 #ifdef NETISR_LOCKING
  923         NETISR_RUNLOCK(&tracker);
  924 #endif
  925         return (error);
  926 }
  927 
  928 int
  929 netisr_queue(u_int proto, struct mbuf *m)
  930 {
  931 
  932         return (netisr_queue_src(proto, 0, m));
  933 }
  934 
  935 /*
  936  * Dispatch a packet for netisr processing; direct dispatch is permitted by
  937  * calling context.
  938  */
  939 int
  940 netisr_dispatch_src(u_int proto, uintptr_t source, struct mbuf *m)
  941 {
  942 #ifdef NETISR_LOCKING
  943         struct rm_priotracker tracker;
  944 #endif
  945         struct netisr_workstream *nwsp;
  946         struct netisr_proto *npp;
  947         struct netisr_work *npwp;
  948         int dosignal, error;
  949         u_int cpuid, dispatch_policy;
  950 
  951         KASSERT(proto < NETISR_MAXPROT,
  952             ("%s: invalid proto %u", __func__, proto));
  953 #ifdef NETISR_LOCKING
  954         NETISR_RLOCK(&tracker);
  955 #endif
  956         npp = &netisr_proto[proto];
  957         KASSERT(npp->np_handler != NULL, ("%s: invalid proto %u", __func__,
  958             proto));
  959 
  960         dispatch_policy = netisr_get_dispatch(npp);
  961         if (dispatch_policy == NETISR_DISPATCH_DEFERRED)
  962                 return (netisr_queue_src(proto, source, m));
  963 
  964         /*
  965          * If direct dispatch is forced, then unconditionally dispatch
  966          * without a formal CPU selection.  Borrow the current CPU's stats,
  967          * even if there's no worker on it.  In this case we don't update
  968          * nws_flags because all netisr processing will be source ordered due
  969          * to always being forced to directly dispatch.
  970          */
  971         if (dispatch_policy == NETISR_DISPATCH_DIRECT) {
  972                 nwsp = DPCPU_PTR(nws);
  973                 npwp = &nwsp->nws_work[proto];
  974                 npwp->nw_dispatched++;
  975                 npwp->nw_handled++;
  976                 netisr_proto[proto].np_handler(m);
  977                 error = 0;
  978                 goto out_unlock;
  979         }
  980 
  981         KASSERT(dispatch_policy == NETISR_DISPATCH_HYBRID,
  982             ("%s: unknown dispatch policy (%u)", __func__, dispatch_policy));
  983 
  984         /*
  985          * Otherwise, we execute in a hybrid mode where we will try to direct
  986          * dispatch if we're on the right CPU and the netisr worker isn't
  987          * already running.
  988          */
  989         sched_pin();
  990         m = netisr_select_cpuid(&netisr_proto[proto], NETISR_DISPATCH_HYBRID,
  991             source, m, &cpuid);
  992         if (m == NULL) {
  993                 error = ENOBUFS;
  994                 goto out_unpin;
  995         }
  996         KASSERT(!CPU_ABSENT(cpuid), ("%s: CPU %u absent", __func__, cpuid));
  997         if (cpuid != curcpu)
  998                 goto queue_fallback;
  999         nwsp = DPCPU_PTR(nws);
 1000         npwp = &nwsp->nws_work[proto];
 1001 
 1002         /*-
 1003          * We are willing to direct dispatch only if three conditions hold:
 1004          *
 1005          * (1) The netisr worker isn't already running,
 1006          * (2) Another thread isn't already directly dispatching, and
 1007          * (3) The netisr hasn't already been woken up.
 1008          */
 1009         NWS_LOCK(nwsp);
 1010         if (nwsp->nws_flags & (NWS_RUNNING | NWS_DISPATCHING | NWS_SCHEDULED)) {
 1011                 error = netisr_queue_workstream(nwsp, proto, npwp, m,
 1012                     &dosignal);
 1013                 NWS_UNLOCK(nwsp);
 1014                 if (dosignal)
 1015                         NWS_SIGNAL(nwsp);
 1016                 goto out_unpin;
 1017         }
 1018 
 1019         /*
 1020          * The current thread is now effectively the netisr worker, so set
 1021          * the dispatching flag to prevent concurrent processing of the
 1022          * stream from another thread (even the netisr worker), which could
 1023          * otherwise lead to effective misordering of the stream.
 1024          */
 1025         nwsp->nws_flags |= NWS_DISPATCHING;
 1026         NWS_UNLOCK(nwsp);
 1027         netisr_proto[proto].np_handler(m);
 1028         NWS_LOCK(nwsp);
 1029         nwsp->nws_flags &= ~NWS_DISPATCHING;
 1030         npwp->nw_handled++;
 1031         npwp->nw_hybrid_dispatched++;
 1032 
 1033         /*
 1034          * If other work was enqueued by another thread while we were direct
 1035          * dispatching, we need to signal the netisr worker to do that work.
 1036          * In the future, we might want to do some of that work in the
 1037          * current thread, rather than trigger further context switches.  If
 1038          * so, we'll want to establish a reasonable bound on the work done in
 1039          * the "borrowed" context.
 1040          */
 1041         if (nwsp->nws_pendingbits != 0) {
 1042                 nwsp->nws_flags |= NWS_SCHEDULED;
 1043                 dosignal = 1;
 1044         } else
 1045                 dosignal = 0;
 1046         NWS_UNLOCK(nwsp);
 1047         if (dosignal)
 1048                 NWS_SIGNAL(nwsp);
 1049         error = 0;
 1050         goto out_unpin;
 1051 
 1052 queue_fallback:
 1053         error = netisr_queue_internal(proto, m, cpuid);
 1054 out_unpin:
 1055         sched_unpin();
 1056 out_unlock:
 1057 #ifdef NETISR_LOCKING
 1058         NETISR_RUNLOCK(&tracker);
 1059 #endif
 1060         return (error);
 1061 }
 1062 
 1063 int
 1064 netisr_dispatch(u_int proto, struct mbuf *m)
 1065 {
 1066 
 1067         return (netisr_dispatch_src(proto, 0, m));
 1068 }
 1069 
 1070 #ifdef DEVICE_POLLING
 1071 /*
 1072  * Kernel polling borrows a netisr thread to run interface polling in; this
 1073  * function allows kernel polling to request that the netisr thread be
 1074  * scheduled even if no packets are pending for protocols.
 1075  */
 1076 void
 1077 netisr_sched_poll(void)
 1078 {
 1079         struct netisr_workstream *nwsp;
 1080 
 1081         nwsp = DPCPU_ID_PTR(nws_array[0], nws);
 1082         NWS_SIGNAL(nwsp);
 1083 }
 1084 #endif
 1085 
 1086 static void
 1087 netisr_start_swi(u_int cpuid, struct pcpu *pc)
 1088 {
 1089         char swiname[12];
 1090         struct netisr_workstream *nwsp;
 1091         int error;
 1092 
 1093         KASSERT(!CPU_ABSENT(cpuid), ("%s: CPU %u absent", __func__, cpuid));
 1094 
 1095         nwsp = DPCPU_ID_PTR(cpuid, nws);
 1096         mtx_init(&nwsp->nws_mtx, "netisr_mtx", NULL, MTX_DEF);
 1097         nwsp->nws_cpu = cpuid;
 1098         snprintf(swiname, sizeof(swiname), "netisr %u", cpuid);
 1099         error = swi_add(&nwsp->nws_intr_event, swiname, swi_net, nwsp,
 1100             SWI_NET, INTR_MPSAFE, &nwsp->nws_swi_cookie);
 1101         if (error)
 1102                 panic("%s: swi_add %d", __func__, error);
 1103         pc->pc_netisr = nwsp->nws_intr_event;
 1104         if (netisr_bindthreads) {
 1105                 error = intr_event_bind(nwsp->nws_intr_event, cpuid);
 1106                 if (error != 0)
 1107                         printf("%s: cpu %u: intr_event_bind: %d", __func__,
 1108                             cpuid, error);
 1109         }
 1110         NETISR_WLOCK();
 1111         nws_array[nws_count] = nwsp->nws_cpu;
 1112         nws_count++;
 1113         NETISR_WUNLOCK();
 1114 }
 1115 
 1116 /*
 1117  * Initialize the netisr subsystem.  We rely on BSS and static initialization
 1118  * of most fields in global data structures.
 1119  *
 1120  * Start a worker thread for the boot CPU so that we can support network
 1121  * traffic immediately in case the network stack is used before additional
 1122  * CPUs are started (for example, diskless boot).
 1123  */
 1124 static void
 1125 netisr_init(void *arg)
 1126 {
 1127         char tmp[NETISR_DISPATCH_POLICY_MAXSTR];
 1128         u_int dispatch_policy;
 1129         int error;
 1130 
 1131         KASSERT(curcpu == 0, ("%s: not on CPU 0", __func__));
 1132 
 1133         NETISR_LOCK_INIT();
 1134         if (netisr_maxthreads == 0 || netisr_maxthreads < -1 )
 1135                 netisr_maxthreads = 1;          /* default behavior */
 1136         else if (netisr_maxthreads == -1)
 1137                 netisr_maxthreads = mp_ncpus;   /* use max cpus */
 1138         if (netisr_maxthreads > mp_ncpus) {
 1139                 printf("netisr_init: forcing maxthreads from %d to %d\n",
 1140                     netisr_maxthreads, mp_ncpus);
 1141                 netisr_maxthreads = mp_ncpus;
 1142         }
 1143         if (netisr_defaultqlimit > netisr_maxqlimit) {
 1144                 printf("netisr_init: forcing defaultqlimit from %d to %d\n",
 1145                     netisr_defaultqlimit, netisr_maxqlimit);
 1146                 netisr_defaultqlimit = netisr_maxqlimit;
 1147         }
 1148 #ifdef DEVICE_POLLING
 1149         /*
 1150          * The device polling code is not yet aware of how to deal with
 1151          * multiple netisr threads, so for the time being compiling in device
 1152          * polling disables parallel netisr workers.
 1153          */
 1154         if (netisr_maxthreads != 1 || netisr_bindthreads != 0) {
 1155                 printf("netisr_init: forcing maxthreads to 1 and "
 1156                     "bindthreads to 0 for device polling\n");
 1157                 netisr_maxthreads = 1;
 1158                 netisr_bindthreads = 0;
 1159         }
 1160 #endif
 1161 
 1162         if (TUNABLE_STR_FETCH("net.isr.dispatch", tmp, sizeof(tmp))) {
 1163                 error = netisr_dispatch_policy_from_str(tmp,
 1164                     &dispatch_policy);
 1165                 if (error == 0 && dispatch_policy == NETISR_DISPATCH_DEFAULT)
 1166                         error = EINVAL;
 1167                 if (error == 0)
 1168                         netisr_dispatch_policy = dispatch_policy;
 1169                 else
 1170                         printf(
 1171                             "%s: invalid dispatch policy %s, using default\n",
 1172                             __func__, tmp);
 1173         }
 1174 
 1175         netisr_start_swi(curcpu, pcpu_find(curcpu));
 1176 }
 1177 SYSINIT(netisr_init, SI_SUB_SOFTINTR, SI_ORDER_FIRST, netisr_init, NULL);
 1178 
 1179 /*
 1180  * Start worker threads for additional CPUs.  No attempt to gracefully handle
 1181  * work reassignment, we don't yet support dynamic reconfiguration.
 1182  */
 1183 static void
 1184 netisr_start(void *arg)
 1185 {
 1186         struct pcpu *pc;
 1187 
 1188         STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) {
 1189                 if (nws_count >= netisr_maxthreads)
 1190                         break;
 1191                 /* XXXRW: Is skipping absent CPUs still required here? */
 1192                 if (CPU_ABSENT(pc->pc_cpuid))
 1193                         continue;
 1194                 /* Worker will already be present for boot CPU. */
 1195                 if (pc->pc_netisr != NULL)
 1196                         continue;
 1197                 netisr_start_swi(pc->pc_cpuid, pc);
 1198         }
 1199 }
 1200 SYSINIT(netisr_start, SI_SUB_SMP, SI_ORDER_MIDDLE, netisr_start, NULL);
 1201 
 1202 /*
 1203  * Sysctl monitoring for netisr: query a list of registered protocols.
 1204  */
 1205 static int
 1206 sysctl_netisr_proto(SYSCTL_HANDLER_ARGS)
 1207 {
 1208         struct rm_priotracker tracker;
 1209         struct sysctl_netisr_proto *snpp, *snp_array;
 1210         struct netisr_proto *npp;
 1211         u_int counter, proto;
 1212         int error;
 1213 
 1214         if (req->newptr != NULL)
 1215                 return (EINVAL);
 1216         snp_array = malloc(sizeof(*snp_array) * NETISR_MAXPROT, M_TEMP,
 1217             M_ZERO | M_WAITOK);
 1218         counter = 0;
 1219         NETISR_RLOCK(&tracker);
 1220         for (proto = 0; proto < NETISR_MAXPROT; proto++) {
 1221                 npp = &netisr_proto[proto];
 1222                 if (npp->np_name == NULL)
 1223                         continue;
 1224                 snpp = &snp_array[counter];
 1225                 snpp->snp_version = sizeof(*snpp);
 1226                 strlcpy(snpp->snp_name, npp->np_name, NETISR_NAMEMAXLEN);
 1227                 snpp->snp_proto = proto;
 1228                 snpp->snp_qlimit = npp->np_qlimit;
 1229                 snpp->snp_policy = npp->np_policy;
 1230                 snpp->snp_dispatch = npp->np_dispatch;
 1231                 if (npp->np_m2flow != NULL)
 1232                         snpp->snp_flags |= NETISR_SNP_FLAGS_M2FLOW;
 1233                 if (npp->np_m2cpuid != NULL)
 1234                         snpp->snp_flags |= NETISR_SNP_FLAGS_M2CPUID;
 1235                 if (npp->np_drainedcpu != NULL)
 1236                         snpp->snp_flags |= NETISR_SNP_FLAGS_DRAINEDCPU;
 1237                 counter++;
 1238         }
 1239         NETISR_RUNLOCK(&tracker);
 1240         KASSERT(counter <= NETISR_MAXPROT,
 1241             ("sysctl_netisr_proto: counter too big (%d)", counter));
 1242         error = SYSCTL_OUT(req, snp_array, sizeof(*snp_array) * counter);
 1243         free(snp_array, M_TEMP);
 1244         return (error);
 1245 }
 1246 
 1247 SYSCTL_PROC(_net_isr, OID_AUTO, proto,
 1248     CTLFLAG_RD|CTLTYPE_STRUCT|CTLFLAG_MPSAFE, 0, 0, sysctl_netisr_proto,
 1249     "S,sysctl_netisr_proto",
 1250     "Return list of protocols registered with netisr");
 1251 
 1252 /*
 1253  * Sysctl monitoring for netisr: query a list of workstreams.
 1254  */
 1255 static int
 1256 sysctl_netisr_workstream(SYSCTL_HANDLER_ARGS)
 1257 {
 1258         struct rm_priotracker tracker;
 1259         struct sysctl_netisr_workstream *snwsp, *snws_array;
 1260         struct netisr_workstream *nwsp;
 1261         u_int counter, cpuid;
 1262         int error;
 1263 
 1264         if (req->newptr != NULL)
 1265                 return (EINVAL);
 1266         snws_array = malloc(sizeof(*snws_array) * MAXCPU, M_TEMP,
 1267             M_ZERO | M_WAITOK);
 1268         counter = 0;
 1269         NETISR_RLOCK(&tracker);
 1270         CPU_FOREACH(cpuid) {
 1271                 nwsp = DPCPU_ID_PTR(cpuid, nws);
 1272                 if (nwsp->nws_intr_event == NULL)
 1273                         continue;
 1274                 NWS_LOCK(nwsp);
 1275                 snwsp = &snws_array[counter];
 1276                 snwsp->snws_version = sizeof(*snwsp);
 1277 
 1278                 /*
 1279                  * For now, we equate workstream IDs and CPU IDs in the
 1280                  * kernel, but expose them independently to userspace in case
 1281                  * that assumption changes in the future.
 1282                  */
 1283                 snwsp->snws_wsid = cpuid;
 1284                 snwsp->snws_cpu = cpuid;
 1285                 if (nwsp->nws_intr_event != NULL)
 1286                         snwsp->snws_flags |= NETISR_SNWS_FLAGS_INTR;
 1287                 NWS_UNLOCK(nwsp);
 1288                 counter++;
 1289         }
 1290         NETISR_RUNLOCK(&tracker);
 1291         KASSERT(counter <= MAXCPU,
 1292             ("sysctl_netisr_workstream: counter too big (%d)", counter));
 1293         error = SYSCTL_OUT(req, snws_array, sizeof(*snws_array) * counter);
 1294         free(snws_array, M_TEMP);
 1295         return (error);
 1296 }
 1297 
 1298 SYSCTL_PROC(_net_isr, OID_AUTO, workstream,
 1299     CTLFLAG_RD|CTLTYPE_STRUCT|CTLFLAG_MPSAFE, 0, 0, sysctl_netisr_workstream,
 1300     "S,sysctl_netisr_workstream",
 1301     "Return list of workstreams implemented by netisr");
 1302 
 1303 /*
 1304  * Sysctl monitoring for netisr: query per-protocol data across all
 1305  * workstreams.
 1306  */
 1307 static int
 1308 sysctl_netisr_work(SYSCTL_HANDLER_ARGS)
 1309 {
 1310         struct rm_priotracker tracker;
 1311         struct sysctl_netisr_work *snwp, *snw_array;
 1312         struct netisr_workstream *nwsp;
 1313         struct netisr_proto *npp;
 1314         struct netisr_work *nwp;
 1315         u_int counter, cpuid, proto;
 1316         int error;
 1317 
 1318         if (req->newptr != NULL)
 1319                 return (EINVAL);
 1320         snw_array = malloc(sizeof(*snw_array) * MAXCPU * NETISR_MAXPROT,
 1321             M_TEMP, M_ZERO | M_WAITOK);
 1322         counter = 0;
 1323         NETISR_RLOCK(&tracker);
 1324         CPU_FOREACH(cpuid) {
 1325                 nwsp = DPCPU_ID_PTR(cpuid, nws);
 1326                 if (nwsp->nws_intr_event == NULL)
 1327                         continue;
 1328                 NWS_LOCK(nwsp);
 1329                 for (proto = 0; proto < NETISR_MAXPROT; proto++) {
 1330                         npp = &netisr_proto[proto];
 1331                         if (npp->np_name == NULL)
 1332                                 continue;
 1333                         nwp = &nwsp->nws_work[proto];
 1334                         snwp = &snw_array[counter];
 1335                         snwp->snw_version = sizeof(*snwp);
 1336                         snwp->snw_wsid = cpuid;         /* See comment above. */
 1337                         snwp->snw_proto = proto;
 1338                         snwp->snw_len = nwp->nw_len;
 1339                         snwp->snw_watermark = nwp->nw_watermark;
 1340                         snwp->snw_dispatched = nwp->nw_dispatched;
 1341                         snwp->snw_hybrid_dispatched =
 1342                             nwp->nw_hybrid_dispatched;
 1343                         snwp->snw_qdrops = nwp->nw_qdrops;
 1344                         snwp->snw_queued = nwp->nw_queued;
 1345                         snwp->snw_handled = nwp->nw_handled;
 1346                         counter++;
 1347                 }
 1348                 NWS_UNLOCK(nwsp);
 1349         }
 1350         KASSERT(counter <= MAXCPU * NETISR_MAXPROT,
 1351             ("sysctl_netisr_work: counter too big (%d)", counter));
 1352         NETISR_RUNLOCK(&tracker);
 1353         error = SYSCTL_OUT(req, snw_array, sizeof(*snw_array) * counter);
 1354         free(snw_array, M_TEMP);
 1355         return (error);
 1356 }
 1357 
 1358 SYSCTL_PROC(_net_isr, OID_AUTO, work,
 1359     CTLFLAG_RD|CTLTYPE_STRUCT|CTLFLAG_MPSAFE, 0, 0, sysctl_netisr_work,
 1360     "S,sysctl_netisr_work",
 1361     "Return list of per-workstream, per-protocol work in netisr");
 1362 
 1363 #ifdef DDB
 1364 DB_SHOW_COMMAND(netisr, db_show_netisr)
 1365 {
 1366         struct netisr_workstream *nwsp;
 1367         struct netisr_work *nwp;
 1368         int first, proto;
 1369         u_int cpuid;
 1370 
 1371         db_printf("%3s %6s %5s %5s %5s %8s %8s %8s %8s\n", "CPU", "Proto",
 1372             "Len", "WMark", "Max", "Disp", "HDisp", "Drop", "Queue");
 1373         CPU_FOREACH(cpuid) {
 1374                 nwsp = DPCPU_ID_PTR(cpuid, nws);
 1375                 if (nwsp->nws_intr_event == NULL)
 1376                         continue;
 1377                 first = 1;
 1378                 for (proto = 0; proto < NETISR_MAXPROT; proto++) {
 1379                         if (netisr_proto[proto].np_handler == NULL)
 1380                                 continue;
 1381                         nwp = &nwsp->nws_work[proto];
 1382                         if (first) {
 1383                                 db_printf("%3d ", cpuid);
 1384                                 first = 0;
 1385                         } else
 1386                                 db_printf("%3s ", "");
 1387                         db_printf(
 1388                             "%6s %5d %5d %5d %8ju %8ju %8ju %8ju\n",
 1389                             netisr_proto[proto].np_name, nwp->nw_len,
 1390                             nwp->nw_watermark, nwp->nw_qlimit,
 1391                             nwp->nw_dispatched, nwp->nw_hybrid_dispatched,
 1392                             nwp->nw_qdrops, nwp->nw_queued);
 1393                 }
 1394         }
 1395 }
 1396 #endif

Cache object: 78342b4c2c9136dea31d2ab2d0272182


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.