freebsd-dev/sys/kern/subr_pcpu.c

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/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 2001 Wind River Systems, Inc.
* All rights reserved.
* Written by: John Baldwin <jhb@FreeBSD.org>
*
* Copyright (c) 2009 Jeffrey Roberson <jeff@freebsd.org>
* All rights reserved.
*
* 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.
* 3. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* 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.
*/
/*
* This module provides MI support for per-cpu data.
*
* Each architecture determines the mapping of logical CPU IDs to physical
* CPUs. The requirements of this mapping are as follows:
* - Logical CPU IDs must reside in the range 0 ... MAXCPU - 1.
* - The mapping is not required to be dense. That is, there may be
* gaps in the mappings.
* - The platform sets the value of MAXCPU in <machine/param.h>.
* - It is suggested, but not required, that in the non-SMP case, the
* platform define MAXCPU to be 1 and define the logical ID of the
* sole CPU as 0.
*/
2003-06-11 00:56:59 +00:00
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ddb.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/pcpu.h>
#include <sys/proc.h>
#include <sys/smp.h>
#include <sys/sx.h>
#include <vm/uma.h>
#include <ddb/ddb.h>
static MALLOC_DEFINE(M_PCPU, "Per-cpu", "Per-cpu resource accouting.");
struct dpcpu_free {
uintptr_t df_start;
int df_len;
TAILQ_ENTRY(dpcpu_free) df_link;
};
static DPCPU_DEFINE(char, modspace[DPCPU_MODMIN]);
static TAILQ_HEAD(, dpcpu_free) dpcpu_head = TAILQ_HEAD_INITIALIZER(dpcpu_head);
static struct sx dpcpu_lock;
uintptr_t dpcpu_off[MAXCPU];
struct pcpu *cpuid_to_pcpu[MAXCPU];
struct cpuhead cpuhead = STAILQ_HEAD_INITIALIZER(cpuhead);
/*
* Initialize the MI portions of a struct pcpu.
*/
void
pcpu_init(struct pcpu *pcpu, int cpuid, size_t size)
{
bzero(pcpu, size);
KASSERT(cpuid >= 0 && cpuid < MAXCPU,
("pcpu_init: invalid cpuid %d", cpuid));
pcpu->pc_cpuid = cpuid;
cpuid_to_pcpu[cpuid] = pcpu;
STAILQ_INSERT_TAIL(&cpuhead, pcpu, pc_allcpu);
cpu_pcpu_init(pcpu, cpuid, size);
pcpu->pc_rm_queue.rmq_next = &pcpu->pc_rm_queue;
pcpu->pc_rm_queue.rmq_prev = &pcpu->pc_rm_queue;
}
void
dpcpu_init(void *dpcpu, int cpuid)
{
struct pcpu *pcpu;
pcpu = pcpu_find(cpuid);
pcpu->pc_dynamic = (uintptr_t)dpcpu - DPCPU_START;
/*
* Initialize defaults from our linker section.
*/
memcpy(dpcpu, (void *)DPCPU_START, DPCPU_BYTES);
/*
* Place it in the global pcpu offset array.
*/
dpcpu_off[cpuid] = pcpu->pc_dynamic;
}
static void
dpcpu_startup(void *dummy __unused)
{
struct dpcpu_free *df;
df = malloc(sizeof(*df), M_PCPU, M_WAITOK | M_ZERO);
df->df_start = (uintptr_t)&DPCPU_NAME(modspace);
df->df_len = DPCPU_MODMIN;
TAILQ_INSERT_HEAD(&dpcpu_head, df, df_link);
sx_init(&dpcpu_lock, "dpcpu alloc lock");
}
SYSINIT(dpcpu, SI_SUB_KLD, SI_ORDER_FIRST, dpcpu_startup, NULL);
/*
* UMA_PCPU_ZONE zones, that are available for all kernel
* consumers. Right now 64 bit zone is used for counter(9)
* and pointer zone is used by flowtable.
*/
uma_zone_t pcpu_zone_64;
uma_zone_t pcpu_zone_ptr;
static void
pcpu_zones_startup(void)
{
pcpu_zone_64 = uma_zcreate("64 pcpu", sizeof(uint64_t),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_PCPU);
if (sizeof(uint64_t) == sizeof(void *))
pcpu_zone_ptr = pcpu_zone_64;
else
pcpu_zone_ptr = uma_zcreate("ptr pcpu", sizeof(void *),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_PCPU);
}
SYSINIT(pcpu_zones, SI_SUB_VM, SI_ORDER_ANY, pcpu_zones_startup, NULL);
/*
* First-fit extent based allocator for allocating space in the per-cpu
* region reserved for modules. This is only intended for use by the
* kernel linkers to place module linker sets.
*/
void *
dpcpu_alloc(int size)
{
struct dpcpu_free *df;
void *s;
s = NULL;
size = roundup2(size, sizeof(void *));
sx_xlock(&dpcpu_lock);
TAILQ_FOREACH(df, &dpcpu_head, df_link) {
if (df->df_len < size)
continue;
if (df->df_len == size) {
s = (void *)df->df_start;
TAILQ_REMOVE(&dpcpu_head, df, df_link);
free(df, M_PCPU);
break;
}
s = (void *)df->df_start;
df->df_len -= size;
df->df_start = df->df_start + size;
break;
}
sx_xunlock(&dpcpu_lock);
return (s);
}
/*
* Free dynamic per-cpu space at module unload time.
*/
void
dpcpu_free(void *s, int size)
{
struct dpcpu_free *df;
struct dpcpu_free *dn;
uintptr_t start;
uintptr_t end;
size = roundup2(size, sizeof(void *));
start = (uintptr_t)s;
end = start + size;
/*
* Free a region of space and merge it with as many neighbors as
* possible. Keeping the list sorted simplifies this operation.
*/
sx_xlock(&dpcpu_lock);
TAILQ_FOREACH(df, &dpcpu_head, df_link) {
if (df->df_start > end)
break;
/*
* If we expand at the end of an entry we may have to
* merge it with the one following it as well.
*/
if (df->df_start + df->df_len == start) {
df->df_len += size;
dn = TAILQ_NEXT(df, df_link);
if (df->df_start + df->df_len == dn->df_start) {
df->df_len += dn->df_len;
TAILQ_REMOVE(&dpcpu_head, dn, df_link);
free(dn, M_PCPU);
}
sx_xunlock(&dpcpu_lock);
return;
}
if (df->df_start == end) {
df->df_start = start;
df->df_len += size;
sx_xunlock(&dpcpu_lock);
return;
}
}
dn = malloc(sizeof(*df), M_PCPU, M_WAITOK | M_ZERO);
dn->df_start = start;
dn->df_len = size;
if (df)
TAILQ_INSERT_BEFORE(df, dn, df_link);
else
TAILQ_INSERT_TAIL(&dpcpu_head, dn, df_link);
sx_xunlock(&dpcpu_lock);
}
/*
* Initialize the per-cpu storage from an updated linker-set region.
*/
void
dpcpu_copy(void *s, int size)
{
#ifdef SMP
uintptr_t dpcpu;
int i;
CPU_FOREACH(i) {
dpcpu = dpcpu_off[i];
if (dpcpu == 0)
continue;
memcpy((void *)(dpcpu + (uintptr_t)s), s, size);
}
#else
memcpy((void *)(dpcpu_off[0] + (uintptr_t)s), s, size);
#endif
}
/*
* Destroy a struct pcpu.
*/
void
pcpu_destroy(struct pcpu *pcpu)
{
STAILQ_REMOVE(&cpuhead, pcpu, pcpu, pc_allcpu);
cpuid_to_pcpu[pcpu->pc_cpuid] = NULL;
dpcpu_off[pcpu->pc_cpuid] = 0;
}
/*
* Locate a struct pcpu by cpu id.
*/
struct pcpu *
pcpu_find(u_int cpuid)
{
return (cpuid_to_pcpu[cpuid]);
}
int
sysctl_dpcpu_quad(SYSCTL_HANDLER_ARGS)
{
uintptr_t dpcpu;
int64_t count;
int i;
count = 0;
CPU_FOREACH(i) {
dpcpu = dpcpu_off[i];
if (dpcpu == 0)
continue;
count += *(int64_t *)(dpcpu + (uintptr_t)arg1);
}
return (SYSCTL_OUT(req, &count, sizeof(count)));
}
int
sysctl_dpcpu_long(SYSCTL_HANDLER_ARGS)
{
uintptr_t dpcpu;
long count;
int i;
count = 0;
CPU_FOREACH(i) {
dpcpu = dpcpu_off[i];
if (dpcpu == 0)
continue;
count += *(long *)(dpcpu + (uintptr_t)arg1);
}
return (SYSCTL_OUT(req, &count, sizeof(count)));
}
int
sysctl_dpcpu_int(SYSCTL_HANDLER_ARGS)
{
uintptr_t dpcpu;
int count;
int i;
count = 0;
CPU_FOREACH(i) {
dpcpu = dpcpu_off[i];
if (dpcpu == 0)
continue;
count += *(int *)(dpcpu + (uintptr_t)arg1);
}
return (SYSCTL_OUT(req, &count, sizeof(count)));
}
#ifdef DDB
DB_SHOW_COMMAND(dpcpu_off, db_show_dpcpu_off)
{
int id;
CPU_FOREACH(id) {
db_printf("dpcpu_off[%2d] = 0x%jx (+ DPCPU_START = %p)\n",
id, (uintmax_t)dpcpu_off[id],
(void *)(uintptr_t)(dpcpu_off[id] + DPCPU_START));
}
}
static void
show_pcpu(struct pcpu *pc)
{
struct thread *td;
db_printf("cpuid = %d\n", pc->pc_cpuid);
db_printf("dynamic pcpu = %p\n", (void *)pc->pc_dynamic);
db_printf("curthread = ");
td = pc->pc_curthread;
if (td != NULL)
db_printf("%p: pid %d tid %d \"%s\"\n", td, td->td_proc->p_pid,
td->td_tid, td->td_name);
else
db_printf("none\n");
db_printf("curpcb = %p\n", pc->pc_curpcb);
db_printf("fpcurthread = ");
td = pc->pc_fpcurthread;
if (td != NULL)
db_printf("%p: pid %d \"%s\"\n", td, td->td_proc->p_pid,
td->td_name);
else
db_printf("none\n");
db_printf("idlethread = ");
td = pc->pc_idlethread;
if (td != NULL)
db_printf("%p: tid %d \"%s\"\n", td, td->td_tid, td->td_name);
else
db_printf("none\n");
db_show_mdpcpu(pc);
Change the curvnet variable from a global const struct vnet *, previously always pointing to the default vnet context, to a dynamically changing thread-local one. The currvnet context should be set on entry to networking code via CURVNET_SET() macros, and reverted to previous state via CURVNET_RESTORE(). Recursions on curvnet are permitted, though strongly discuouraged. This change should have no functional impact on nooptions VIMAGE kernel builds, where CURVNET_* macros expand to whitespace. The curthread->td_vnet (aka curvnet) variable's purpose is to be an indicator of the vnet context in which the current network-related operation takes place, in case we cannot deduce the current vnet context from any other source, such as by looking at mbuf's m->m_pkthdr.rcvif->if_vnet, sockets's so->so_vnet etc. Moreover, so far curvnet has turned out to be an invaluable consistency checking aid: it helps to catch cases when sockets, ifnets or any other vnet-aware structures may have leaked from one vnet to another. The exact placement of the CURVNET_SET() / CURVNET_RESTORE() macros was a result of an empirical iterative process, whith an aim to reduce recursions on CURVNET_SET() to a minimum, while still reducing the scope of CURVNET_SET() to networking only operations - the alternative would be calling CURVNET_SET() on each system call entry. In general, curvnet has to be set in three typicall cases: when processing socket-related requests from userspace or from within the kernel; when processing inbound traffic flowing from device drivers to upper layers of the networking stack, and when executing timer-driven networking functions. This change also introduces a DDB subcommand to show the list of all vnet instances. Approved by: julian (mentor)
2009-05-05 10:56:12 +00:00
#ifdef VIMAGE
db_printf("curvnet = %p\n", pc->pc_curthread->td_vnet);
#endif
#ifdef WITNESS
db_printf("spin locks held:\n");
witness_list_locks(&pc->pc_spinlocks, db_printf);
#endif
}
DB_SHOW_COMMAND(pcpu, db_show_pcpu)
{
struct pcpu *pc;
int id;
if (have_addr)
id = ((addr >> 4) % 16) * 10 + (addr % 16);
else
id = PCPU_GET(cpuid);
pc = pcpu_find(id);
if (pc == NULL) {
db_printf("CPU %d not found\n", id);
return;
}
show_pcpu(pc);
}
DB_SHOW_ALL_COMMAND(pcpu, db_show_cpu_all)
{
struct pcpu *pc;
int id;
db_printf("Current CPU: %d\n\n", PCPU_GET(cpuid));
CPU_FOREACH(id) {
pc = pcpu_find(id);
if (pc != NULL) {
show_pcpu(pc);
db_printf("\n");
}
}
}
DB_SHOW_ALIAS(allpcpu, db_show_cpu_all);
#endif