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/*- * Copyright (c) 2007-2009 Robert N. M. Watson * Copyright (c) 2010-2011 Juniper Networks, Inc. * All rights reserved. * * This software was developed by Robert N. M. Watson under contract * to Juniper Networks, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include <sys/cdefs.h> __FBSDID("$FreeBSD: release/9.1.0/sys/net/netisr.c 222531 2011-05-31 15:11:43Z nwhitehorn $"); /* * netisr is a packet dispatch service, allowing synchronous (directly * dispatched) and asynchronous (deferred dispatch) processing of packets by * registered protocol handlers. Callers pass a protocol identifier and * packet to netisr, along with a direct dispatch hint, and work will either * be immediately processed by the registered handler, or passed to a * software interrupt (SWI) thread for deferred dispatch. Callers will * generally select one or the other based on: * * - Whether directly dispatching a netisr handler lead to code reentrance or * lock recursion, such as entering the socket code from the socket code. * - Whether directly dispatching a netisr handler lead to recursive * processing, such as when decapsulating several wrapped layers of tunnel * information (IPSEC within IPSEC within ...). * * Maintaining ordering for protocol streams is a critical design concern. * Enforcing ordering limits the opportunity for concurrency, but maintains * the strong ordering requirements found in some protocols, such as TCP. Of * related concern is CPU affinity--it is desirable to process all data * associated with a particular stream on the same CPU over time in order to * avoid acquiring locks associated with the connection on different CPUs, * keep connection data in one cache, and to generally encourage associated * user threads to live on the same CPU as the stream. It's also desirable * to avoid lock migration and contention where locks are associated with * more than one flow. * * netisr supports several policy variations, represented by the * NETISR_POLICY_* constants, allowing protocols to play various roles in * identifying flows, assigning work to CPUs, etc. These are described in * netisr.h. */ #include "opt_ddb.h" #include "opt_device_polling.h" #include <sys/param.h> #include <sys/bus.h> #include <sys/kernel.h> #include <sys/kthread.h> #include <sys/interrupt.h> #include <sys/lock.h> #include <sys/mbuf.h> #include <sys/mutex.h> #include <sys/pcpu.h> #include <sys/proc.h> #include <sys/rmlock.h> #include <sys/sched.h> #include <sys/smp.h> #include <sys/socket.h> #include <sys/sysctl.h> #include <sys/systm.h> #ifdef DDB #include <ddb/ddb.h> #endif #define _WANT_NETISR_INTERNAL /* Enable definitions from netisr_internal.h */ #include <net/if.h> #include <net/if_var.h> #include <net/netisr.h> #include <net/netisr_internal.h> #include <net/vnet.h> /*- * Synchronize use and modification of the registered netisr data structures; * acquire a read lock while modifying the set of registered protocols to * prevent partially registered or unregistered protocols from being run. * * The following data structures and fields are protected by this lock: * * - The netisr_proto array, including all fields of struct netisr_proto. * - The nws array, including all fields of struct netisr_worker. * - The nws_array array. * * Note: the NETISR_LOCKING define controls whether read locks are acquired * in packet processing paths requiring netisr registration stability. This * is disabled by default as it can lead to measurable performance * degradation even with rmlocks (3%-6% for loopback ping-pong traffic), and * because netisr registration and unregistration is extremely rare at * runtime. If it becomes more common, this decision should be revisited. * * XXXRW: rmlocks don't support assertions. */ static struct rmlock netisr_rmlock; #define NETISR_LOCK_INIT() rm_init_flags(&netisr_rmlock, "netisr", \ RM_NOWITNESS) #define NETISR_LOCK_ASSERT() #define NETISR_RLOCK(tracker) rm_rlock(&netisr_rmlock, (tracker)) #define NETISR_RUNLOCK(tracker) rm_runlock(&netisr_rmlock, (tracker)) #define NETISR_WLOCK() rm_wlock(&netisr_rmlock) #define NETISR_WUNLOCK() rm_wunlock(&netisr_rmlock) /* #define NETISR_LOCKING */ SYSCTL_NODE(_net, OID_AUTO, isr, CTLFLAG_RW, 0, "netisr"); /*- * Three global direct dispatch policies are supported: * * NETISR_DISPATCH_QUEUED: All work is deferred for a netisr, regardless of * context (may be overriden by protocols). * * NETISR_DISPATCH_HYBRID: If the executing context allows direct dispatch, * and we're running on the CPU the work would be performed on, then direct * dispatch it if it wouldn't violate ordering constraints on the workstream. * * NETISR_DISPATCH_DIRECT: If the executing context allows direct dispatch, * always direct dispatch. (The default.) * * Notice that changing the global policy could lead to short periods of * misordered processing, but this is considered acceptable as compared to * the complexity of enforcing ordering during policy changes. Protocols can * override the global policy (when they're not doing that, they select * NETISR_DISPATCH_DEFAULT). */ #define NETISR_DISPATCH_POLICY_DEFAULT NETISR_DISPATCH_DIRECT #define NETISR_DISPATCH_POLICY_MAXSTR 20 /* Used for temporary buffers. */ static u_int netisr_dispatch_policy = NETISR_DISPATCH_POLICY_DEFAULT; static int sysctl_netisr_dispatch_policy(SYSCTL_HANDLER_ARGS); SYSCTL_PROC(_net_isr, OID_AUTO, dispatch, CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_TUN, 0, 0, sysctl_netisr_dispatch_policy, "A", "netisr dispatch policy"); /* * These sysctls were used in previous versions to control and export * dispatch policy state. Now, we provide read-only export via them so that * older netstat binaries work. At some point they can be garbage collected. */ static int netisr_direct_force; SYSCTL_INT(_net_isr, OID_AUTO, direct_force, CTLFLAG_RD, &netisr_direct_force, 0, "compat: force direct dispatch"); static int netisr_direct; SYSCTL_INT(_net_isr, OID_AUTO, direct, CTLFLAG_RD, &netisr_direct, 0, "compat: enable direct dispatch"); /* * Allow the administrator to limit the number of threads (CPUs) to use for * netisr. We don't check netisr_maxthreads before creating the thread for * CPU 0, so in practice we ignore values <= 1. This must be set at boot. * We will create at most one thread per CPU. */ static int netisr_maxthreads = -1; /* Max number of threads. */ TUNABLE_INT("net.isr.maxthreads", &netisr_maxthreads); SYSCTL_INT(_net_isr, OID_AUTO, maxthreads, CTLFLAG_RDTUN, &netisr_maxthreads, 0, "Use at most this many CPUs for netisr processing"); static int netisr_bindthreads = 0; /* Bind threads to CPUs. */ TUNABLE_INT("net.isr.bindthreads", &netisr_bindthreads); SYSCTL_INT(_net_isr, OID_AUTO, bindthreads, CTLFLAG_RDTUN, &netisr_bindthreads, 0, "Bind netisr threads to CPUs."); /* * Limit per-workstream mbuf queue limits s to at most net.isr.maxqlimit, * both for initial configuration and later modification using * netisr_setqlimit(). */ #define NETISR_DEFAULT_MAXQLIMIT 10240 static u_int netisr_maxqlimit = NETISR_DEFAULT_MAXQLIMIT; TUNABLE_INT("net.isr.maxqlimit", &netisr_maxqlimit); SYSCTL_UINT(_net_isr, OID_AUTO, maxqlimit, CTLFLAG_RDTUN, &netisr_maxqlimit, 0, "Maximum netisr per-protocol, per-CPU queue depth."); /* * The default per-workstream mbuf queue limit for protocols that don't * initialize the nh_qlimit field of their struct netisr_handler. If this is * set above netisr_maxqlimit, we truncate it to the maximum during boot. */ #define NETISR_DEFAULT_DEFAULTQLIMIT 256 static u_int netisr_defaultqlimit = NETISR_DEFAULT_DEFAULTQLIMIT; TUNABLE_INT("net.isr.defaultqlimit", &netisr_defaultqlimit); SYSCTL_UINT(_net_isr, OID_AUTO, defaultqlimit, CTLFLAG_RDTUN, &netisr_defaultqlimit, 0, "Default netisr per-protocol, per-CPU queue limit if not set by protocol"); /* * Store and export the compile-time constant NETISR_MAXPROT limit on the * number of protocols that can register with netisr at a time. This is * required for crashdump analysis, as it sizes netisr_proto[]. */ static u_int netisr_maxprot = NETISR_MAXPROT; SYSCTL_UINT(_net_isr, OID_AUTO, maxprot, CTLFLAG_RD, &netisr_maxprot, 0, "Compile-time limit on the number of protocols supported by netisr."); /* * The netisr_proto array describes all registered protocols, indexed by * protocol number. See netisr_internal.h for more details. */ static struct netisr_proto netisr_proto[NETISR_MAXPROT]; /* * Per-CPU workstream data. See netisr_internal.h for more details. */ DPCPU_DEFINE(struct netisr_workstream, nws); /* * Map contiguous values between 0 and nws_count into CPU IDs appropriate for * accessing workstreams. This allows constructions of the form * DPCPU_ID_GET(nws_array[arbitraryvalue % nws_count], nws). */ static u_int nws_array[MAXCPU]; /* * Number of registered workstreams. Will be at most the number of running * CPUs once fully started. */ static u_int nws_count; SYSCTL_UINT(_net_isr, OID_AUTO, numthreads, CTLFLAG_RD, &nws_count, 0, "Number of extant netisr threads."); /* * Synchronization for each workstream: a mutex protects all mutable fields * in each stream, including per-protocol state (mbuf queues). The SWI is * woken up if asynchronous dispatch is required. */ #define NWS_LOCK(s) mtx_lock(&(s)->nws_mtx) #define NWS_LOCK_ASSERT(s) mtx_assert(&(s)->nws_mtx, MA_OWNED) #define NWS_UNLOCK(s) mtx_unlock(&(s)->nws_mtx) #define NWS_SIGNAL(s) swi_sched((s)->nws_swi_cookie, 0) /* * Utility routines for protocols that implement their own mapping of flows * to CPUs. */ u_int netisr_get_cpucount(void) { return (nws_count); } u_int netisr_get_cpuid(u_int cpunumber) { KASSERT(cpunumber < nws_count, ("%s: %u > %u", __func__, cpunumber, nws_count)); return (nws_array[cpunumber]); } /* * The default implementation of flow -> CPU ID mapping. * * Non-static so that protocols can use it to map their own work to specific * CPUs in a manner consistent to netisr for affinity purposes. */ u_int netisr_default_flow2cpu(u_int flowid) { return (nws_array[flowid % nws_count]); } /* * Dispatch tunable and sysctl configuration. */ struct netisr_dispatch_table_entry { u_int ndte_policy; const char *ndte_policy_str; }; static const struct netisr_dispatch_table_entry netisr_dispatch_table[] = { { NETISR_DISPATCH_DEFAULT, "default" }, { NETISR_DISPATCH_DEFERRED, "deferred" }, { NETISR_DISPATCH_HYBRID, "hybrid" }, { NETISR_DISPATCH_DIRECT, "direct" }, }; static const u_int netisr_dispatch_table_len = (sizeof(netisr_dispatch_table) / sizeof(netisr_dispatch_table[0])); static void netisr_dispatch_policy_to_str(u_int dispatch_policy, char *buffer, u_int buflen) { const struct netisr_dispatch_table_entry *ndtep; const char *str; u_int i; str = "unknown"; for (i = 0; i < netisr_dispatch_table_len; i++) { ndtep = &netisr_dispatch_table[i]; if (ndtep->ndte_policy == dispatch_policy) { str = ndtep->ndte_policy_str; break; } } snprintf(buffer, buflen, "%s", str); } static int netisr_dispatch_policy_from_str(const char *str, u_int *dispatch_policyp) { const struct netisr_dispatch_table_entry *ndtep; u_int i; for (i = 0; i < netisr_dispatch_table_len; i++) { ndtep = &netisr_dispatch_table[i]; if (strcmp(ndtep->ndte_policy_str, str) == 0) { *dispatch_policyp = ndtep->ndte_policy; return (0); } } return (EINVAL); } static void netisr_dispatch_policy_compat(void) { switch (netisr_dispatch_policy) { case NETISR_DISPATCH_DEFERRED: netisr_direct_force = 0; netisr_direct = 0; break; case NETISR_DISPATCH_HYBRID: netisr_direct_force = 0; netisr_direct = 1; break; case NETISR_DISPATCH_DIRECT: netisr_direct_force = 1; netisr_direct = 1; break; default: panic("%s: unknown policy %u", __func__, netisr_dispatch_policy); } } static int sysctl_netisr_dispatch_policy(SYSCTL_HANDLER_ARGS) { char tmp[NETISR_DISPATCH_POLICY_MAXSTR]; u_int dispatch_policy; int error; netisr_dispatch_policy_to_str(netisr_dispatch_policy, tmp, sizeof(tmp)); error = sysctl_handle_string(oidp, tmp, sizeof(tmp), req); if (error == 0 && req->newptr != NULL) { error = netisr_dispatch_policy_from_str(tmp, &dispatch_policy); if (error == 0 && dispatch_policy == NETISR_DISPATCH_DEFAULT) error = EINVAL; if (error == 0) { netisr_dispatch_policy = dispatch_policy; netisr_dispatch_policy_compat(); } } return (error); } /* * Register a new netisr handler, which requires initializing per-protocol * fields for each workstream. All netisr work is briefly suspended while * the protocol is installed. */ void netisr_register(const struct netisr_handler *nhp) { struct netisr_work *npwp; const char *name; u_int i, proto; proto = nhp->nh_proto; name = nhp->nh_name; /* * Test that the requested registration is valid. */ KASSERT(nhp->nh_name != NULL, ("%s: nh_name NULL for %u", __func__, proto)); KASSERT(nhp->nh_handler != NULL, ("%s: nh_handler NULL for %s", __func__, name)); KASSERT(nhp->nh_policy == NETISR_POLICY_SOURCE || nhp->nh_policy == NETISR_POLICY_FLOW || nhp->nh_policy == NETISR_POLICY_CPU, ("%s: unsupported nh_policy %u for %s", __func__, nhp->nh_policy, name)); KASSERT(nhp->nh_policy == NETISR_POLICY_FLOW || nhp->nh_m2flow == NULL, ("%s: nh_policy != FLOW but m2flow defined for %s", __func__, name)); KASSERT(nhp->nh_policy == NETISR_POLICY_CPU || nhp->nh_m2cpuid == NULL, ("%s: nh_policy != CPU but m2cpuid defined for %s", __func__, name)); KASSERT(nhp->nh_policy != NETISR_POLICY_CPU || nhp->nh_m2cpuid != NULL, ("%s: nh_policy == CPU but m2cpuid not defined for %s", __func__, name)); KASSERT(nhp->nh_dispatch == NETISR_DISPATCH_DEFAULT || nhp->nh_dispatch == NETISR_DISPATCH_DEFERRED || nhp->nh_dispatch == NETISR_DISPATCH_HYBRID || nhp->nh_dispatch == NETISR_DISPATCH_DIRECT, ("%s: invalid nh_dispatch (%u)", __func__, nhp->nh_dispatch)); KASSERT(proto < NETISR_MAXPROT, ("%s(%u, %s): protocol too big", __func__, proto, name)); /* * Test that no existing registration exists for this protocol. */ NETISR_WLOCK(); KASSERT(netisr_proto[proto].np_name == NULL, ("%s(%u, %s): name present", __func__, proto, name)); KASSERT(netisr_proto[proto].np_handler == NULL, ("%s(%u, %s): handler present", __func__, proto, name)); netisr_proto[proto].np_name = name; netisr_proto[proto].np_handler = nhp->nh_handler; netisr_proto[proto].np_m2flow = nhp->nh_m2flow; netisr_proto[proto].np_m2cpuid = nhp->nh_m2cpuid; netisr_proto[proto].np_drainedcpu = nhp->nh_drainedcpu; if (nhp->nh_qlimit == 0) netisr_proto[proto].np_qlimit = netisr_defaultqlimit; else if (nhp->nh_qlimit > netisr_maxqlimit) { printf("%s: %s requested queue limit %u capped to " "net.isr.maxqlimit %u\n", __func__, name, nhp->nh_qlimit, netisr_maxqlimit); netisr_proto[proto].np_qlimit = netisr_maxqlimit; } else netisr_proto[proto].np_qlimit = nhp->nh_qlimit; netisr_proto[proto].np_policy = nhp->nh_policy; netisr_proto[proto].np_dispatch = nhp->nh_dispatch; CPU_FOREACH(i) { npwp = &(DPCPU_ID_PTR(i, nws))->nws_work[proto]; bzero(npwp, sizeof(*npwp)); npwp->nw_qlimit = netisr_proto[proto].np_qlimit; } NETISR_WUNLOCK(); } /* * Clear drop counters across all workstreams for a protocol. */ void netisr_clearqdrops(const struct netisr_handler *nhp) { struct netisr_work *npwp; #ifdef INVARIANTS const char *name; #endif u_int i, proto; proto = nhp->nh_proto; #ifdef INVARIANTS name = nhp->nh_name; #endif KASSERT(proto < NETISR_MAXPROT, ("%s(%u): protocol too big for %s", __func__, proto, name)); NETISR_WLOCK(); KASSERT(netisr_proto[proto].np_handler != NULL, ("%s(%u): protocol not registered for %s", __func__, proto, name)); CPU_FOREACH(i) { npwp = &(DPCPU_ID_PTR(i, nws))->nws_work[proto]; npwp->nw_qdrops = 0; } NETISR_WUNLOCK(); } /* * Query current drop counters across all workstreams for a protocol. */ void netisr_getqdrops(const struct netisr_handler *nhp, u_int64_t *qdropp) { struct netisr_work *npwp; struct rm_priotracker tracker; #ifdef INVARIANTS const char *name; #endif u_int i, proto; *qdropp = 0; proto = nhp->nh_proto; #ifdef INVARIANTS name = nhp->nh_name; #endif KASSERT(proto < NETISR_MAXPROT, ("%s(%u): protocol too big for %s", __func__, proto, name)); NETISR_RLOCK(&tracker); KASSERT(netisr_proto[proto].np_handler != NULL, ("%s(%u): protocol not registered for %s", __func__, proto, name)); CPU_FOREACH(i) { npwp = &(DPCPU_ID_PTR(i, nws))->nws_work[proto]; *qdropp += npwp->nw_qdrops; } NETISR_RUNLOCK(&tracker); } /* * Query current per-workstream queue limit for a protocol. */ void netisr_getqlimit(const struct netisr_handler *nhp, u_int *qlimitp) { struct rm_priotracker tracker; #ifdef INVARIANTS const char *name; #endif u_int proto; proto = nhp->nh_proto; #ifdef INVARIANTS name = nhp->nh_name; #endif KASSERT(proto < NETISR_MAXPROT, ("%s(%u): protocol too big for %s", __func__, proto, name)); NETISR_RLOCK(&tracker); KASSERT(netisr_proto[proto].np_handler != NULL, ("%s(%u): protocol not registered for %s", __func__, proto, name)); *qlimitp = netisr_proto[proto].np_qlimit; NETISR_RUNLOCK(&tracker); } /* * Update the queue limit across per-workstream queues for a protocol. We * simply change the limits, and don't drain overflowed packets as they will * (hopefully) take care of themselves shortly. */ int netisr_setqlimit(const struct netisr_handler *nhp, u_int qlimit) { struct netisr_work *npwp; #ifdef INVARIANTS const char *name; #endif u_int i, proto; if (qlimit > netisr_maxqlimit) return (EINVAL); proto = nhp->nh_proto; #ifdef INVARIANTS name = nhp->nh_name; #endif KASSERT(proto < NETISR_MAXPROT, ("%s(%u): protocol too big for %s", __func__, proto, name)); NETISR_WLOCK(); KASSERT(netisr_proto[proto].np_handler != NULL, ("%s(%u): protocol not registered for %s", __func__, proto, name)); netisr_proto[proto].np_qlimit = qlimit; CPU_FOREACH(i) { npwp = &(DPCPU_ID_PTR(i, nws))->nws_work[proto]; npwp->nw_qlimit = qlimit; } NETISR_WUNLOCK(); return (0); } /* * Drain all packets currently held in a particular protocol work queue. */ static void netisr_drain_proto(struct netisr_work *npwp) { struct mbuf *m; /* * We would assert the lock on the workstream but it's not passed in. */ while ((m = npwp->nw_head) != NULL) { npwp->nw_head = m->m_nextpkt; m->m_nextpkt = NULL; if (npwp->nw_head == NULL) npwp->nw_tail = NULL; npwp->nw_len--; m_freem(m); } KASSERT(npwp->nw_tail == NULL, ("%s: tail", __func__)); KASSERT(npwp->nw_len == 0, ("%s: len", __func__)); } /* * Remove the registration of a network protocol, which requires clearing * per-protocol fields across all workstreams, including freeing all mbufs in * the queues at time of unregister. All work in netisr is briefly suspended * while this takes place. */ void netisr_unregister(const struct netisr_handler *nhp) { struct netisr_work *npwp; #ifdef INVARIANTS const char *name; #endif u_int i, proto; proto = nhp->nh_proto; #ifdef INVARIANTS name = nhp->nh_name; #endif KASSERT(proto < NETISR_MAXPROT, ("%s(%u): protocol too big for %s", __func__, proto, name)); NETISR_WLOCK(); KASSERT(netisr_proto[proto].np_handler != NULL, ("%s(%u): protocol not registered for %s", __func__, proto, name)); netisr_proto[proto].np_name = NULL; netisr_proto[proto].np_handler = NULL; netisr_proto[proto].np_m2flow = NULL; netisr_proto[proto].np_m2cpuid = NULL; netisr_proto[proto].np_qlimit = 0; netisr_proto[proto].np_policy = 0; CPU_FOREACH(i) { npwp = &(DPCPU_ID_PTR(i, nws))->nws_work[proto]; netisr_drain_proto(npwp); bzero(npwp, sizeof(*npwp)); } NETISR_WUNLOCK(); } /* * Compose the global and per-protocol policies on dispatch, and return the * dispatch policy to use. */ static u_int netisr_get_dispatch(struct netisr_proto *npp) { /* * Protocol-specific configuration overrides the global default. */ if (npp->np_dispatch != NETISR_DISPATCH_DEFAULT) return (npp->np_dispatch); return (netisr_dispatch_policy); } /* * Look up the workstream given a packet and source identifier. Do this by * checking the protocol's policy, and optionally call out to the protocol * for assistance if required. */ static struct mbuf * netisr_select_cpuid(struct netisr_proto *npp, u_int dispatch_policy, uintptr_t source, struct mbuf *m, u_int *cpuidp) { struct ifnet *ifp; u_int policy; NETISR_LOCK_ASSERT(); /* * In the event we have only one worker, shortcut and deliver to it * without further ado. */ if (nws_count == 1) { *cpuidp = nws_array[0]; return (m); } /* * What happens next depends on the policy selected by the protocol. * If we want to support per-interface policies, we should do that * here first. */ policy = npp->np_policy; if (policy == NETISR_POLICY_CPU) { m = npp->np_m2cpuid(m, source, cpuidp); if (m == NULL) return (NULL); /* * It's possible for a protocol not to have a good idea about * where to process a packet, in which case we fall back on * the netisr code to decide. In the hybrid case, return the * current CPU ID, which will force an immediate direct * dispatch. In the queued case, fall back on the SOURCE * policy. */ if (*cpuidp != NETISR_CPUID_NONE) return (m); if (dispatch_policy == NETISR_DISPATCH_HYBRID) { *cpuidp = curcpu; return (m); } policy = NETISR_POLICY_SOURCE; } if (policy == NETISR_POLICY_FLOW) { if (!(m->m_flags & M_FLOWID) && npp->np_m2flow != NULL) { m = npp->np_m2flow(m, source); if (m == NULL) return (NULL); } if (m->m_flags & M_FLOWID) { *cpuidp = netisr_default_flow2cpu(m->m_pkthdr.flowid); return (m); } policy = NETISR_POLICY_SOURCE; } KASSERT(policy == NETISR_POLICY_SOURCE, ("%s: invalid policy %u for %s", __func__, npp->np_policy, npp->np_name)); ifp = m->m_pkthdr.rcvif; if (ifp != NULL) *cpuidp = nws_array[(ifp->if_index + source) % nws_count]; else *cpuidp = nws_array[source % nws_count]; return (m); } /* * Process packets associated with a workstream and protocol. For reasons of * fairness, we process up to one complete netisr queue at a time, moving the * queue to a stack-local queue for processing, but do not loop refreshing * from the global queue. The caller is responsible for deciding whether to * loop, and for setting the NWS_RUNNING flag. The passed workstream will be * locked on entry and relocked before return, but will be released while * processing. The number of packets processed is returned. */ static u_int netisr_process_workstream_proto(struct netisr_workstream *nwsp, u_int proto) { struct netisr_work local_npw, *npwp; u_int handled; struct mbuf *m; NETISR_LOCK_ASSERT(); NWS_LOCK_ASSERT(nwsp); KASSERT(nwsp->nws_flags & NWS_RUNNING, ("%s(%u): not running", __func__, proto)); KASSERT(proto >= 0 && proto < NETISR_MAXPROT, ("%s(%u): invalid proto\n", __func__, proto)); npwp = &nwsp->nws_work[proto]; if (npwp->nw_len == 0) return (0); /* * Move the global work queue to a thread-local work queue. * * Notice that this means the effective maximum length of the queue * is actually twice that of the maximum queue length specified in * the protocol registration call. */ handled = npwp->nw_len; local_npw = *npwp; npwp->nw_head = NULL; npwp->nw_tail = NULL; npwp->nw_len = 0; nwsp->nws_pendingbits &= ~(1 << proto); NWS_UNLOCK(nwsp); while ((m = local_npw.nw_head) != NULL) { local_npw.nw_head = m->m_nextpkt; m->m_nextpkt = NULL; if (local_npw.nw_head == NULL) local_npw.nw_tail = NULL; local_npw.nw_len--; VNET_ASSERT(m->m_pkthdr.rcvif != NULL, ("%s:%d rcvif == NULL: m=%p", __func__, __LINE__, m)); CURVNET_SET(m->m_pkthdr.rcvif->if_vnet); netisr_proto[proto].np_handler(m); CURVNET_RESTORE(); } KASSERT(local_npw.nw_len == 0, ("%s(%u): len %u", __func__, proto, local_npw.nw_len)); if (netisr_proto[proto].np_drainedcpu) netisr_proto[proto].np_drainedcpu(nwsp->nws_cpu); NWS_LOCK(nwsp); npwp->nw_handled += handled; return (handled); } /* * SWI handler for netisr -- processes packets in a set of workstreams that * it owns, woken up by calls to NWS_SIGNAL(). If this workstream is already * being direct dispatched, go back to sleep and wait for the dispatching * thread to wake us up again. */ static void swi_net(void *arg) { #ifdef NETISR_LOCKING struct rm_priotracker tracker; #endif struct netisr_workstream *nwsp; u_int bits, prot; nwsp = arg; #ifdef DEVICE_POLLING KASSERT(nws_count == 1, ("%s: device_polling but nws_count != 1", __func__)); netisr_poll(); #endif #ifdef NETISR_LOCKING NETISR_RLOCK(&tracker); #endif NWS_LOCK(nwsp); KASSERT(!(nwsp->nws_flags & NWS_RUNNING), ("swi_net: running")); if (nwsp->nws_flags & NWS_DISPATCHING) goto out; nwsp->nws_flags |= NWS_RUNNING; nwsp->nws_flags &= ~NWS_SCHEDULED; while ((bits = nwsp->nws_pendingbits) != 0) { while ((prot = ffs(bits)) != 0) { prot--; bits &= ~(1 << prot); (void)netisr_process_workstream_proto(nwsp, prot); } } nwsp->nws_flags &= ~NWS_RUNNING; out: NWS_UNLOCK(nwsp); #ifdef NETISR_LOCKING NETISR_RUNLOCK(&tracker); #endif #ifdef DEVICE_POLLING netisr_pollmore(); #endif } static int netisr_queue_workstream(struct netisr_workstream *nwsp, u_int proto, struct netisr_work *npwp, struct mbuf *m, int *dosignalp) { NWS_LOCK_ASSERT(nwsp); *dosignalp = 0; if (npwp->nw_len < npwp->nw_qlimit) { m->m_nextpkt = NULL; if (npwp->nw_head == NULL) { npwp->nw_head = m; npwp->nw_tail = m; } else { npwp->nw_tail->m_nextpkt = m; npwp->nw_tail = m; } npwp->nw_len++; if (npwp->nw_len > npwp->nw_watermark) npwp->nw_watermark = npwp->nw_len; /* * We must set the bit regardless of NWS_RUNNING, so that * swi_net() keeps calling netisr_process_workstream_proto(). */ nwsp->nws_pendingbits |= (1 << proto); if (!(nwsp->nws_flags & (NWS_RUNNING | NWS_DISPATCHING | NWS_SCHEDULED))) { nwsp->nws_flags |= NWS_SCHEDULED; *dosignalp = 1; /* Defer until unlocked. */ } npwp->nw_queued++; return (0); } else { m_freem(m); npwp->nw_qdrops++; return (ENOBUFS); } } static int netisr_queue_internal(u_int proto, struct mbuf *m, u_int cpuid) { struct netisr_workstream *nwsp; struct netisr_work *npwp; int dosignal, error; #ifdef NETISR_LOCKING NETISR_LOCK_ASSERT(); #endif KASSERT(cpuid <= mp_maxid, ("%s: cpuid too big (%u, %u)", __func__, cpuid, mp_maxid)); KASSERT(!CPU_ABSENT(cpuid), ("%s: CPU %u absent", __func__, cpuid)); dosignal = 0; error = 0; nwsp = DPCPU_ID_PTR(cpuid, nws); npwp = &nwsp->nws_work[proto]; NWS_LOCK(nwsp); error = netisr_queue_workstream(nwsp, proto, npwp, m, &dosignal); NWS_UNLOCK(nwsp); if (dosignal) NWS_SIGNAL(nwsp); return (error); } int netisr_queue_src(u_int proto, uintptr_t source, struct mbuf *m) { #ifdef NETISR_LOCKING struct rm_priotracker tracker; #endif u_int cpuid; int error; KASSERT(proto < NETISR_MAXPROT, ("%s: invalid proto %u", __func__, proto)); #ifdef NETISR_LOCKING NETISR_RLOCK(&tracker); #endif KASSERT(netisr_proto[proto].np_handler != NULL, ("%s: invalid proto %u", __func__, proto)); m = netisr_select_cpuid(&netisr_proto[proto], NETISR_DISPATCH_DEFERRED, source, m, &cpuid); if (m != NULL) { KASSERT(!CPU_ABSENT(cpuid), ("%s: CPU %u absent", __func__, cpuid)); error = netisr_queue_internal(proto, m, cpuid); } else error = ENOBUFS; #ifdef NETISR_LOCKING NETISR_RUNLOCK(&tracker); #endif return (error); } int netisr_queue(u_int proto, struct mbuf *m) { return (netisr_queue_src(proto, 0, m)); } /* * Dispatch a packet for netisr processing; direct dispatch is permitted by * calling context. */ int netisr_dispatch_src(u_int proto, uintptr_t source, struct mbuf *m) { #ifdef NETISR_LOCKING struct rm_priotracker tracker; #endif struct netisr_workstream *nwsp; struct netisr_proto *npp; struct netisr_work *npwp; int dosignal, error; u_int cpuid, dispatch_policy; KASSERT(proto < NETISR_MAXPROT, ("%s: invalid proto %u", __func__, proto)); #ifdef NETISR_LOCKING NETISR_RLOCK(&tracker); #endif npp = &netisr_proto[proto]; KASSERT(npp->np_handler != NULL, ("%s: invalid proto %u", __func__, proto)); dispatch_policy = netisr_get_dispatch(npp); if (dispatch_policy == NETISR_DISPATCH_DEFERRED) return (netisr_queue_src(proto, source, m)); /* * If direct dispatch is forced, then unconditionally dispatch * without a formal CPU selection. Borrow the current CPU's stats, * even if there's no worker on it. In this case we don't update * nws_flags because all netisr processing will be source ordered due * to always being forced to directly dispatch. */ if (dispatch_policy == NETISR_DISPATCH_DIRECT) { nwsp = DPCPU_PTR(nws); npwp = &nwsp->nws_work[proto]; npwp->nw_dispatched++; npwp->nw_handled++; netisr_proto[proto].np_handler(m); error = 0; goto out_unlock; } KASSERT(dispatch_policy == NETISR_DISPATCH_HYBRID, ("%s: unknown dispatch policy (%u)", __func__, dispatch_policy)); /* * Otherwise, we execute in a hybrid mode where we will try to direct * dispatch if we're on the right CPU and the netisr worker isn't * already running. */ sched_pin(); m = netisr_select_cpuid(&netisr_proto[proto], NETISR_DISPATCH_HYBRID, source, m, &cpuid); if (m == NULL) { error = ENOBUFS; goto out_unpin; } KASSERT(!CPU_ABSENT(cpuid), ("%s: CPU %u absent", __func__, cpuid)); if (cpuid != curcpu) goto queue_fallback; nwsp = DPCPU_PTR(nws); npwp = &nwsp->nws_work[proto]; /*- * We are willing to direct dispatch only if three conditions hold: * * (1) The netisr worker isn't already running, * (2) Another thread isn't already directly dispatching, and * (3) The netisr hasn't already been woken up. */ NWS_LOCK(nwsp); if (nwsp->nws_flags & (NWS_RUNNING | NWS_DISPATCHING | NWS_SCHEDULED)) { error = netisr_queue_workstream(nwsp, proto, npwp, m, &dosignal); NWS_UNLOCK(nwsp); if (dosignal) NWS_SIGNAL(nwsp); goto out_unpin; } /* * The current thread is now effectively the netisr worker, so set * the dispatching flag to prevent concurrent processing of the * stream from another thread (even the netisr worker), which could * otherwise lead to effective misordering of the stream. */ nwsp->nws_flags |= NWS_DISPATCHING; NWS_UNLOCK(nwsp); netisr_proto[proto].np_handler(m); NWS_LOCK(nwsp); nwsp->nws_flags &= ~NWS_DISPATCHING; npwp->nw_handled++; npwp->nw_hybrid_dispatched++; /* * If other work was enqueued by another thread while we were direct * dispatching, we need to signal the netisr worker to do that work. * In the future, we might want to do some of that work in the * current thread, rather than trigger further context switches. If * so, we'll want to establish a reasonable bound on the work done in * the "borrowed" context. */ if (nwsp->nws_pendingbits != 0) { nwsp->nws_flags |= NWS_SCHEDULED; dosignal = 1; } else dosignal = 0; NWS_UNLOCK(nwsp); if (dosignal) NWS_SIGNAL(nwsp); error = 0; goto out_unpin; queue_fallback: error = netisr_queue_internal(proto, m, cpuid); out_unpin: sched_unpin(); out_unlock: #ifdef NETISR_LOCKING NETISR_RUNLOCK(&tracker); #endif return (error); } int netisr_dispatch(u_int proto, struct mbuf *m) { return (netisr_dispatch_src(proto, 0, m)); } #ifdef DEVICE_POLLING /* * Kernel polling borrows a netisr thread to run interface polling in; this * function allows kernel polling to request that the netisr thread be * scheduled even if no packets are pending for protocols. */ void netisr_sched_poll(void) { struct netisr_workstream *nwsp; nwsp = DPCPU_ID_PTR(nws_array[0], nws); NWS_SIGNAL(nwsp); } #endif static void netisr_start_swi(u_int cpuid, struct pcpu *pc) { char swiname[12]; struct netisr_workstream *nwsp; int error; KASSERT(!CPU_ABSENT(cpuid), ("%s: CPU %u absent", __func__, cpuid)); nwsp = DPCPU_ID_PTR(cpuid, nws); mtx_init(&nwsp->nws_mtx, "netisr_mtx", NULL, MTX_DEF); nwsp->nws_cpu = cpuid; snprintf(swiname, sizeof(swiname), "netisr %u", cpuid); error = swi_add(&nwsp->nws_intr_event, swiname, swi_net, nwsp, SWI_NET, INTR_MPSAFE, &nwsp->nws_swi_cookie); if (error) panic("%s: swi_add %d", __func__, error); pc->pc_netisr = nwsp->nws_intr_event; if (netisr_bindthreads) { error = intr_event_bind(nwsp->nws_intr_event, cpuid); if (error != 0) printf("%s: cpu %u: intr_event_bind: %d", __func__, cpuid, error); } NETISR_WLOCK(); nws_array[nws_count] = nwsp->nws_cpu; nws_count++; NETISR_WUNLOCK(); } /* * Initialize the netisr subsystem. We rely on BSS and static initialization * of most fields in global data structures. * * Start a worker thread for the boot CPU so that we can support network * traffic immediately in case the network stack is used before additional * CPUs are started (for example, diskless boot). */ static void netisr_init(void *arg) { char tmp[NETISR_DISPATCH_POLICY_MAXSTR]; u_int dispatch_policy; int error; KASSERT(curcpu == 0, ("%s: not on CPU 0", __func__)); NETISR_LOCK_INIT(); if (netisr_maxthreads < 1) netisr_maxthreads = 1; if (netisr_maxthreads > mp_ncpus) { printf("netisr_init: forcing maxthreads from %d to %d\n", netisr_maxthreads, mp_ncpus); netisr_maxthreads = mp_ncpus; } if (netisr_defaultqlimit > netisr_maxqlimit) { printf("netisr_init: forcing defaultqlimit from %d to %d\n", netisr_defaultqlimit, netisr_maxqlimit); netisr_defaultqlimit = netisr_maxqlimit; } #ifdef DEVICE_POLLING /* * The device polling code is not yet aware of how to deal with * multiple netisr threads, so for the time being compiling in device * polling disables parallel netisr workers. */ if (netisr_maxthreads != 1 || netisr_bindthreads != 0) { printf("netisr_init: forcing maxthreads to 1 and " "bindthreads to 0 for device polling\n"); netisr_maxthreads = 1; netisr_bindthreads = 0; } #endif if (TUNABLE_STR_FETCH("net.isr.dispatch", tmp, sizeof(tmp))) { error = netisr_dispatch_policy_from_str(tmp, &dispatch_policy); if (error == 0 && dispatch_policy == NETISR_DISPATCH_DEFAULT) error = EINVAL; if (error == 0) { netisr_dispatch_policy = dispatch_policy; netisr_dispatch_policy_compat(); } else printf( "%s: invalid dispatch policy %s, using default\n", __func__, tmp); } netisr_start_swi(curcpu, pcpu_find(curcpu)); } SYSINIT(netisr_init, SI_SUB_SOFTINTR, SI_ORDER_FIRST, netisr_init, NULL); /* * Start worker threads for additional CPUs. No attempt to gracefully handle * work reassignment, we don't yet support dynamic reconfiguration. */ static void netisr_start(void *arg) { struct pcpu *pc; STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) { if (nws_count >= netisr_maxthreads) break; /* XXXRW: Is skipping absent CPUs still required here? */ if (CPU_ABSENT(pc->pc_cpuid)) continue; /* Worker will already be present for boot CPU. */ if (pc->pc_netisr != NULL) continue; netisr_start_swi(pc->pc_cpuid, pc); } } SYSINIT(netisr_start, SI_SUB_SMP, SI_ORDER_MIDDLE, netisr_start, NULL); /* * Sysctl monitoring for netisr: query a list of registered protocols. */ static int sysctl_netisr_proto(SYSCTL_HANDLER_ARGS) { struct rm_priotracker tracker; struct sysctl_netisr_proto *snpp, *snp_array; struct netisr_proto *npp; u_int counter, proto; int error; if (req->newptr != NULL) return (EINVAL); snp_array = malloc(sizeof(*snp_array) * NETISR_MAXPROT, M_TEMP, M_ZERO | M_WAITOK); counter = 0; NETISR_RLOCK(&tracker); for (proto = 0; proto < NETISR_MAXPROT; proto++) { npp = &netisr_proto[proto]; if (npp->np_name == NULL) continue; snpp = &snp_array[counter]; snpp->snp_version = sizeof(*snpp); strlcpy(snpp->snp_name, npp->np_name, NETISR_NAMEMAXLEN); snpp->snp_proto = proto; snpp->snp_qlimit = npp->np_qlimit; snpp->snp_policy = npp->np_policy; snpp->snp_dispatch = npp->np_dispatch; if (npp->np_m2flow != NULL) snpp->snp_flags |= NETISR_SNP_FLAGS_M2FLOW; if (npp->np_m2cpuid != NULL) snpp->snp_flags |= NETISR_SNP_FLAGS_M2CPUID; if (npp->np_drainedcpu != NULL) snpp->snp_flags |= NETISR_SNP_FLAGS_DRAINEDCPU; counter++; } NETISR_RUNLOCK(&tracker); KASSERT(counter <= NETISR_MAXPROT, ("sysctl_netisr_proto: counter too big (%d)", counter)); error = SYSCTL_OUT(req, snp_array, sizeof(*snp_array) * counter); free(snp_array, M_TEMP); return (error); } SYSCTL_PROC(_net_isr, OID_AUTO, proto, CTLFLAG_RD|CTLTYPE_STRUCT|CTLFLAG_MPSAFE, 0, 0, sysctl_netisr_proto, "S,sysctl_netisr_proto", "Return list of protocols registered with netisr"); /* * Sysctl monitoring for netisr: query a list of workstreams. */ static int sysctl_netisr_workstream(SYSCTL_HANDLER_ARGS) { struct rm_priotracker tracker; struct sysctl_netisr_workstream *snwsp, *snws_array; struct netisr_workstream *nwsp; u_int counter, cpuid; int error; if (req->newptr != NULL) return (EINVAL); snws_array = malloc(sizeof(*snws_array) * MAXCPU, M_TEMP, M_ZERO | M_WAITOK); counter = 0; NETISR_RLOCK(&tracker); CPU_FOREACH(cpuid) { nwsp = DPCPU_ID_PTR(cpuid, nws); if (nwsp->nws_intr_event == NULL) continue; NWS_LOCK(nwsp); snwsp = &snws_array[counter]; snwsp->snws_version = sizeof(*snwsp); /* * For now, we equate workstream IDs and CPU IDs in the * kernel, but expose them independently to userspace in case * that assumption changes in the future. */ snwsp->snws_wsid = cpuid; snwsp->snws_cpu = cpuid; if (nwsp->nws_intr_event != NULL) snwsp->snws_flags |= NETISR_SNWS_FLAGS_INTR; NWS_UNLOCK(nwsp); counter++; } NETISR_RUNLOCK(&tracker); KASSERT(counter <= MAXCPU, ("sysctl_netisr_workstream: counter too big (%d)", counter)); error = SYSCTL_OUT(req, snws_array, sizeof(*snws_array) * counter); free(snws_array, M_TEMP); return (error); } SYSCTL_PROC(_net_isr, OID_AUTO, workstream, CTLFLAG_RD|CTLTYPE_STRUCT|CTLFLAG_MPSAFE, 0, 0, sysctl_netisr_workstream, "S,sysctl_netisr_workstream", "Return list of workstreams implemented by netisr"); /* * Sysctl monitoring for netisr: query per-protocol data across all * workstreams. */ static int sysctl_netisr_work(SYSCTL_HANDLER_ARGS) { struct rm_priotracker tracker; struct sysctl_netisr_work *snwp, *snw_array; struct netisr_workstream *nwsp; struct netisr_proto *npp; struct netisr_work *nwp; u_int counter, cpuid, proto; int error; if (req->newptr != NULL) return (EINVAL); snw_array = malloc(sizeof(*snw_array) * MAXCPU * NETISR_MAXPROT, M_TEMP, M_ZERO | M_WAITOK); counter = 0; NETISR_RLOCK(&tracker); CPU_FOREACH(cpuid) { nwsp = DPCPU_ID_PTR(cpuid, nws); if (nwsp->nws_intr_event == NULL) continue; NWS_LOCK(nwsp); for (proto = 0; proto < NETISR_MAXPROT; proto++) { npp = &netisr_proto[proto]; if (npp->np_name == NULL) continue; nwp = &nwsp->nws_work[proto]; snwp = &snw_array[counter]; snwp->snw_version = sizeof(*snwp); snwp->snw_wsid = cpuid; /* See comment above. */ snwp->snw_proto = proto; snwp->snw_len = nwp->nw_len; snwp->snw_watermark = nwp->nw_watermark; snwp->snw_dispatched = nwp->nw_dispatched; snwp->snw_hybrid_dispatched = nwp->nw_hybrid_dispatched; snwp->snw_qdrops = nwp->nw_qdrops; snwp->snw_queued = nwp->nw_queued; snwp->snw_handled = nwp->nw_handled; counter++; } NWS_UNLOCK(nwsp); } KASSERT(counter <= MAXCPU * NETISR_MAXPROT, ("sysctl_netisr_work: counter too big (%d)", counter)); NETISR_RUNLOCK(&tracker); error = SYSCTL_OUT(req, snw_array, sizeof(*snw_array) * counter); free(snw_array, M_TEMP); return (error); } SYSCTL_PROC(_net_isr, OID_AUTO, work, CTLFLAG_RD|CTLTYPE_STRUCT|CTLFLAG_MPSAFE, 0, 0, sysctl_netisr_work, "S,sysctl_netisr_work", "Return list of per-workstream, per-protocol work in netisr"); #ifdef DDB DB_SHOW_COMMAND(netisr, db_show_netisr) { struct netisr_workstream *nwsp; struct netisr_work *nwp; int first, proto; u_int cpuid; db_printf("%3s %6s %5s %5s %5s %8s %8s %8s %8s\n", "CPU", "Proto", "Len", "WMark", "Max", "Disp", "HDisp", "Drop", "Queue"); CPU_FOREACH(cpuid) { nwsp = DPCPU_ID_PTR(cpuid, nws); if (nwsp->nws_intr_event == NULL) continue; first = 1; for (proto = 0; proto < NETISR_MAXPROT; proto++) { if (netisr_proto[proto].np_handler == NULL) continue; nwp = &nwsp->nws_work[proto]; if (first) { db_printf("%3d ", cpuid); first = 0; } else db_printf("%3s ", ""); db_printf( "%6s %5d %5d %5d %8ju %8ju %8ju %8ju\n", netisr_proto[proto].np_name, nwp->nw_len, nwp->nw_watermark, nwp->nw_qlimit, nwp->nw_dispatched, nwp->nw_hybrid_dispatched, nwp->nw_qdrops, nwp->nw_queued); } } } #endif