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vpp/svm/svm.c
Dave Barach 309bef25f1 Enable shared-VM namespace support 
Required prep work for gracefully supporting
"... dpdk { proc-type secondary }" -  multiple processes sharing a physical
host, VM, container, etc.

Change-Id: Ic3eb72f4093e26d7c86dde3b8799264f1d0c218b
Signed-off-by: Dave Barach <dave@barachs.net>
2016-01-22 16:10:07 -05:00

1047 lines
28 KiB
C
Raw Blame History

/*
*------------------------------------------------------------------
* svm.c - shared VM allocation, mmap(...MAP_FIXED...)
* library
*
* Copyright (c) 2009 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*------------------------------------------------------------------
*/
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <netinet/in.h>
#include <signal.h>
#include <pthread.h>
#include <unistd.h>
#include <time.h>
#include <fcntl.h>
#include <string.h>
#include <vppinfra/clib.h>
#include <vppinfra/vec.h>
#include <vppinfra/hash.h>
#include <vppinfra/bitmap.h>
#include <vppinfra/fifo.h>
#include <vppinfra/time.h>
#include <vppinfra/mheap.h>
#include <vppinfra/heap.h>
#include <vppinfra/pool.h>
#include <vppinfra/format.h>
#include "svm.h"
static svm_region_t *root_rp;
static int root_rp_refcount;
#define MAXLOCK 2
static pthread_mutex_t *mutexes_held [MAXLOCK];
static int nheld;
svm_region_t *svm_get_root_rp (void)
{
return root_rp;
}
#define MUTEX_DEBUG
static void region_lock(svm_region_t *rp, int tag)
{
pthread_mutex_lock(&rp->mutex);
#ifdef MUTEX_DEBUG
rp->mutex_owner_pid = getpid();
rp->mutex_owner_tag = tag;
#endif
ASSERT(nheld < MAXLOCK);
/*
* Keep score of held mutexes so we can try to exit
* cleanly if the world comes to an end at the worst possible
* moment
*/
mutexes_held [nheld++] = &rp->mutex;
}
static void region_unlock(svm_region_t *rp)
{
int i,j;
#ifdef MUTEX_DEBUG
rp->mutex_owner_pid = 0;
rp->mutex_owner_tag = 0;
#endif
for (i = nheld-1; i >= 0; i--) {
if (mutexes_held[i] == &rp->mutex) {
for (j = i; j < MAXLOCK-1; j++)
mutexes_held[j] = mutexes_held[j+1];
nheld--;
goto found;
}
}
ASSERT(0);
found:
CLIB_MEMORY_BARRIER();
pthread_mutex_unlock(&rp->mutex);
}
static u8 * format_svm_flags (u8 * s, va_list * args)
{
uword f = va_arg (*args, uword);
if (f & SVM_FLAGS_MHEAP)
s = format (s, "MHEAP ");
if (f & SVM_FLAGS_FILE)
s = format (s, "FILE ");
if (f & SVM_FLAGS_NODATA)
s = format (s, "NODATA ");
if (f & SVM_FLAGS_NEED_DATA_INIT)
s = format (s, "INIT ");
return (s);
}
static u8 * format_svm_size (u8 * s, va_list * args)
{
uword size = va_arg (*args, uword);
if (size >= (1<<20)) {
s = format (s, "(%d mb)", size >> 20);
} else if (size >= (1<<10)) {
s = format (s, "(%d kb)", size >> 10);
} else {
s = format (s, "(%d bytes)", size);
}
return (s);
}
u8 * format_svm_region (u8 * s, va_list * args)
{
svm_region_t *rp = va_arg (*args, svm_region_t *);
int verbose = va_arg (*args, int);
int i;
uword lo, hi;
s = format (s, "%s: base va 0x%x size 0x%x %U\n",
rp->region_name, rp->virtual_base,
rp->virtual_size, format_svm_size, rp->virtual_size);
s = format (s, " user_ctx 0x%x, bitmap_size %d\n",
rp->user_ctx, rp->bitmap_size);
if (verbose) {
s = format (s, " flags: 0x%x %U\n", rp->flags,
format_svm_flags, rp->flags);
s = format (s,
" region_heap 0x%x data_base 0x%x data_heap 0x%x\n",
rp->region_heap, rp->data_base, rp->data_heap);
}
s = format (s, " %d clients, pids: ",
vec_len(rp->client_pids));
for (i = 0; i < vec_len(rp->client_pids); i++)
s = format (s, "%d ", rp->client_pids[i]);
s = format (s, "\n");
if (verbose) {
lo = hi = ~0;
s = format (s, " VM in use: ");
for (i = 0; i < rp->bitmap_size; i++) {
if (clib_bitmap_get_no_check (rp->bitmap, i) != 0) {
if (lo == ~0) {
hi = lo = rp->virtual_base + i*MMAP_PAGESIZE;
} else {
hi = rp->virtual_base + i*MMAP_PAGESIZE;
}
} else {
if (lo != ~0) {
hi = rp->virtual_base + i*MMAP_PAGESIZE -1;
s = format (s, " 0x%x - 0x%x (%dk)\n", lo, hi,
(hi - lo)>>10);
lo = hi = ~0;
}
}
}
s = format (s, " rgn heap stats: %U", format_mheap,
rp->region_heap, 0);
if ((rp->flags & SVM_FLAGS_MHEAP) && rp->data_heap) {
s = format (s, "\n data heap stats: %U", format_mheap,
rp->data_heap, 1);
}
s = format (s, "\n");
}
return(s);
}
/*
* rnd_pagesize
* Round to a pagesize multiple, presumably 4k works
*/
static unsigned int rnd_pagesize(unsigned int size)
{
unsigned int rv;
rv = (size + (MMAP_PAGESIZE-1)) & ~(MMAP_PAGESIZE-1);
return(rv);
}
/*
* svm_data_region_setup
*/
static int svm_data_region_create (svm_map_region_args_t *a,
svm_region_t *rp)
{
int fd;
u8 junk = 0;
uword map_size;
map_size = rp->virtual_size - (MMAP_PAGESIZE + SVM_PVT_MHEAP_SIZE);
if (a->flags & SVM_FLAGS_FILE) {
struct stat statb;
fd = open (a->backing_file, O_RDWR | O_CREAT, 0777);
if (fd < 0) {
clib_unix_warning ("open");
return -1;
}
if (fstat(fd, &statb) < 0) {
clib_unix_warning("fstat");
return -2;
}
if (statb.st_mode & S_IFREG) {
if (statb.st_size == 0) {
lseek(fd, map_size, SEEK_SET);
if (write(fd, &junk, 1) != 1)
clib_unix_warning ("set region size");
} else {
map_size = rnd_pagesize (statb.st_size);
}
} else {
map_size = a->backing_mmap_size;
}
ASSERT(map_size <= rp->virtual_size -
(MMAP_PAGESIZE + SVM_PVT_MHEAP_SIZE));
if (mmap (rp->data_base, map_size, PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_FIXED, fd, 0) == MAP_FAILED) {
clib_unix_warning("mmap");
return -3;
}
close(fd);
rp->backing_file = (char *) format(0, "%s\0", a->backing_file);
rp->flags |= SVM_FLAGS_FILE;
}
if (a->flags & SVM_FLAGS_MHEAP) {
rp->data_heap =
mheap_alloc_with_flags ((void *)(rp->data_base), map_size,
MHEAP_FLAG_DISABLE_VM);
rp->flags |= SVM_FLAGS_MHEAP;
}
return 0;
}
static int svm_data_region_map (svm_map_region_args_t *a,
svm_region_t *rp)
{
int fd;
u8 junk = 0;
uword map_size;
struct stat statb;
map_size = rp->virtual_size - (MMAP_PAGESIZE + SVM_PVT_MHEAP_SIZE);
if (a->flags & SVM_FLAGS_FILE) {
fd = open (a->backing_file, O_RDWR, 0777);
if (fd < 0) {
clib_unix_warning ("open");
return -1;
}
if (fstat(fd, &statb) < 0) {
clib_unix_warning("fstat");
return -2;
}
if (statb.st_mode & S_IFREG) {
if (statb.st_size == 0) {
lseek(fd, map_size, SEEK_SET);
if (write(fd, &junk, 1) != 1)
clib_unix_warning ("set region size");
} else {
map_size = rnd_pagesize (statb.st_size);
}
} else {
map_size = a->backing_mmap_size;
}
ASSERT(map_size <= rp->virtual_size
- (MMAP_PAGESIZE + SVM_PVT_MHEAP_SIZE));
if (mmap (rp->data_base, map_size, PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_FIXED, fd, 0) == MAP_FAILED) {
clib_unix_warning("mmap");
return -3;
}
close(fd);
}
return 0;
}
u8 *shm_name_from_svm_map_region_args (svm_map_region_args_t *a)
{
u8 *path;
u8 *shm_name;
u8 *split_point;
u8 *mkdir_arg = 0;
int root_path_offset = 0;
int name_offset = 0;
if (a->root_path) {
/* Tolerate present or absent slashes */
if (a->root_path[0] == '/')
root_path_offset++;
/* create the root_path under /dev/shm
iterate through path creating directories */
path = format (0, "/dev/shm/%s%c", &a->root_path[root_path_offset], 0);
split_point = path+1;
vec_add1(mkdir_arg, '-');
while (*split_point) {
while (*split_point && *split_point != '/') {
vec_add1 (mkdir_arg, *split_point);
split_point++;
}
vec_add1 (mkdir_arg, 0);
/* ready to descend another level */
mkdir_arg[vec_len(mkdir_arg)-1] = '-';
split_point++;
}
vec_free(mkdir_arg);
vec_free(path);
if (a->name[0] == '/')
name_offset = 1;
shm_name = format (0, "/%s-%s%c", a->root_path,
&a->name[name_offset], 0);
}
else
shm_name = format (0, "%s%c", a->name, 0);
return (shm_name);
}
/*
* svm_map_region
*/
void *svm_map_region (svm_map_region_args_t *a)
{
int svm_fd;
svm_region_t *rp;
pthread_mutexattr_t attr;
pthread_condattr_t cattr;
int deadman=0;
u8 junk = 0;
void *oldheap;
int overhead_space;
int rv;
uword data_base;
int nbits, words, bit;
int pid_holding_region_lock;
u8 *shm_name;
int dead_region_recovery = 0;
int time_left;
struct stat stat;
struct timespec ts, tsrem;
if (CLIB_DEBUG > 1)
clib_warning ("[%d] map region %s", getpid(), a->name);
ASSERT((a->size & ~(MMAP_PAGESIZE-1)) == a->size);
ASSERT(a->name);
shm_name = shm_name_from_svm_map_region_args (a);
svm_fd = shm_open((char *) shm_name, O_RDWR | O_CREAT | O_EXCL, 0777);
if (svm_fd >= 0) {
vec_free(shm_name);
lseek(svm_fd, a->size, SEEK_SET);
if (write(svm_fd, &junk, 1) != 1)
clib_warning ("set region size");
rp = mmap((void *)a->baseva, a->size,
PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FIXED, svm_fd, 0);
if (rp == (svm_region_t *) MAP_FAILED) {
clib_unix_warning ("mmap create");
return (0);
}
close(svm_fd);
memset(rp, 0, sizeof(*rp));
if (pthread_mutexattr_init(&attr))
clib_unix_warning("mutexattr_init");
if (pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_SHARED))
clib_unix_warning("mutexattr_setpshared");
if (pthread_mutex_init(&rp->mutex, &attr))
clib_unix_warning("mutex_init");
if (pthread_mutexattr_destroy(&attr))
clib_unix_warning("mutexattr_destroy");
if (pthread_condattr_init(&cattr))
clib_unix_warning("condattr_init");
if (pthread_condattr_setpshared(&cattr, PTHREAD_PROCESS_SHARED))
clib_unix_warning("condattr_setpshared");
if (pthread_cond_init(&rp->condvar, &cattr))
clib_unix_warning("cond_init");
if(pthread_condattr_destroy(&cattr))
clib_unix_warning("condattr_destroy");
region_lock (rp, 1);
rp->virtual_base = a->baseva;
rp->virtual_size = a->size;
rp->region_heap =
mheap_alloc_with_flags ((void *)(a->baseva+MMAP_PAGESIZE),
SVM_PVT_MHEAP_SIZE,
MHEAP_FLAG_DISABLE_VM);
oldheap = svm_push_pvt_heap(rp);
rp->region_name = (char *)format (0, "%s%c", a->name, 0);
vec_add1(rp->client_pids, getpid());
nbits = rp->virtual_size / MMAP_PAGESIZE;
ASSERT (nbits > 0);
rp->bitmap_size = nbits;
words = (nbits + BITS(uword)-1) / BITS(uword);
vec_validate (rp->bitmap, words-1);
overhead_space = MMAP_PAGESIZE /* header */ +
SVM_PVT_MHEAP_SIZE;
bit = 0;
data_base = (uword)rp->virtual_base;
if (a->flags & SVM_FLAGS_NODATA)
rp->flags |= SVM_FLAGS_NEED_DATA_INIT;
do {
clib_bitmap_set_no_check (rp->bitmap, bit, 1);
bit++;
overhead_space -= MMAP_PAGESIZE;
data_base += MMAP_PAGESIZE;
} while (overhead_space > 0);
rp->data_base = (void *)data_base;
/*
* Note: although the POSIX spec guarantees that only one
* process enters this block, we have to play games
* to hold off clients until e.g. the mutex is ready
*/
rp->version = SVM_VERSION;
/* setup the data portion of the region */
rv = svm_data_region_create (a, rp);
if (rv) {
clib_warning ("data_region_create: %d", rv);
}
region_unlock(rp);
svm_pop_heap(oldheap);
return ((void *) rp);
} else {
svm_fd = shm_open((char *)shm_name, O_RDWR, 0777);
vec_free(shm_name);
if (svm_fd < 0) {
perror("svm_region_map(mmap open)");
return (0);
}
time_left = 20;
while (1) {
if (0 != fstat(svm_fd, &stat)) {
clib_warning("fstat failed: %d", errno);
return (0);
}
if (stat.st_size > 0) {
break;
}
if (0 == time_left) {
clib_warning("waiting for resize of shm file timed out");
return (0);
}
ts.tv_sec = 0;
ts.tv_nsec = 100000000;
while (nanosleep(&ts, &tsrem) < 0)
ts = tsrem;
time_left--;
}
rp = mmap(0, MMAP_PAGESIZE,
PROT_READ | PROT_WRITE, MAP_SHARED, svm_fd, 0);
if (rp == (svm_region_t *) MAP_FAILED) {
close(svm_fd);
clib_warning("mmap");
return (0);
}
/*
* We lost the footrace to create this region; make sure
* the winner has crossed the finish line.
*/
while (rp->version == 0 && deadman++ < 5) {
sleep(1);
}
/*
* <bleep>-ed?
*/
if (rp->version == 0) {
close(svm_fd);
munmap(rp, a->size);
clib_warning("rp->version %d not %d", rp->version,
SVM_VERSION);
return (0);
}
/* Remap now that the region has been placed */
a->baseva = rp->virtual_base;
a->size = rp->virtual_size;
munmap(rp, MMAP_PAGESIZE);
rp = (void *) mmap ((void *)a->baseva, a->size,
PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_FIXED, svm_fd, 0);
if ((uword)rp == (uword)MAP_FAILED) {
clib_unix_warning ("mmap");
return (0);
}
if ((uword) rp != rp->virtual_base) {
clib_warning("mmap botch");
}
/*
* Try to fix the region mutex if it is held by
* a dead process
*/
pid_holding_region_lock = rp->mutex_owner_pid;
if (pid_holding_region_lock &&
kill (pid_holding_region_lock, 0) < 0) {
clib_warning (
"region %s mutex held by dead pid %d, tag %d, force unlock",
rp->region_name, pid_holding_region_lock, rp->mutex_owner_tag);
/* owner pid is nonexistent */
rp->mutex.__data.__owner = 0;
rp->mutex.__data.__lock = 0;
dead_region_recovery = 1;
}
if (dead_region_recovery)
clib_warning ("recovery: attempt to re-lock region");
region_lock(rp, 2);
oldheap = svm_push_pvt_heap (rp);
vec_add1(rp->client_pids, getpid());
if (dead_region_recovery)
clib_warning ("recovery: attempt svm_data_region_map");
rv = svm_data_region_map (a, rp);
if (rv) {
clib_warning ("data_region_map: %d", rv);
}
if (dead_region_recovery)
clib_warning ("unlock and continue");
region_unlock(rp);
svm_pop_heap(oldheap);
return ((void *) rp);
}
return 0; /* NOTREACHED */
}
static void svm_mutex_cleanup (void)
{
int i;
for (i = 0; i < nheld; i++) {
pthread_mutex_unlock (mutexes_held[i]);
}
}
static void svm_region_init_internal (char *root_path)
{
svm_region_t *rp;
svm_map_region_args_t *a=0;
u64 ticks = clib_cpu_time_now();
uword randomize_baseva;
/* guard against klutz calls */
root_rp_refcount++;
if (root_rp)
return;
atexit(svm_mutex_cleanup);
/* Randomize the shared-VM base at init time */
if (MMAP_PAGESIZE <= (4<<10))
randomize_baseva = (ticks & 15) * MMAP_PAGESIZE;
else
randomize_baseva = (ticks & 3) * MMAP_PAGESIZE;
vec_validate(a,0);
a->root_path = root_path;
a->name = SVM_GLOBAL_REGION_NAME;
a->baseva = SVM_GLOBAL_REGION_BASEVA + randomize_baseva;
a->size = SVM_GLOBAL_REGION_SIZE;
a->flags = SVM_FLAGS_NODATA;
rp = svm_map_region (a);
ASSERT(rp);
region_lock(rp, 3);
/* Set up the main region data structures */
if (rp->flags & SVM_FLAGS_NEED_DATA_INIT) {
svm_main_region_t *mp = 0;
void *oldheap;
rp->flags &= ~(SVM_FLAGS_NEED_DATA_INIT);
oldheap = svm_push_pvt_heap (rp);
vec_validate (mp, 0);
mp->name_hash = hash_create_string (0, sizeof(uword));
mp->root_path = root_path
? format (0, "%s%c", root_path, 0) : 0 ;
rp->data_base = mp;
svm_pop_heap (oldheap);
}
region_unlock(rp);
vec_free (a);
root_rp = rp;
}
void svm_region_init (void)
{
svm_region_init_internal (0);
}
void svm_region_init_chroot (char *root_path)
{
svm_region_init_internal (root_path);
}
void *svm_region_find_or_create (svm_map_region_args_t *a)
{
svm_main_region_t *mp;
svm_region_t *rp;
uword need_nbits;
int index, i;
void *oldheap;
uword *p;
u8 *name;
svm_subregion_t *subp;
ASSERT(root_rp);
a->size += MMAP_PAGESIZE + SVM_PVT_MHEAP_SIZE;
a->size = rnd_pagesize(a->size);
region_lock (root_rp, 4);
oldheap = svm_push_pvt_heap(root_rp);
mp = root_rp->data_base;
ASSERT(mp);
/* Map the named region from the correct chroot environment */
a->root_path = (char *) mp->root_path;
/*
* See if this region is already known. If it is, we're
* almost done...
*/
p = hash_get_mem (mp->name_hash, a->name);
if (p) {
rp = svm_map_region (a);
region_unlock(root_rp);
svm_pop_heap (oldheap);
return rp;
}
/* Create the region. */
ASSERT((a->size & ~(MMAP_PAGESIZE-1)) == a->size);
need_nbits = a->size / MMAP_PAGESIZE;
index = 1; /* $$$ fixme, figure out how many bit to really skip */
/*
* Scan the virtual space allocation bitmap, looking for a large
* enough chunk
*/
do {
if (clib_bitmap_get_no_check(root_rp->bitmap, index) == 0) {
for (i = 0; i < (need_nbits-1); i++) {
if (clib_bitmap_get_no_check(root_rp->bitmap,
index+i) == 1) {
index = index + i;
goto next;
}
}
break;
}
index++;
next:;
} while (index < root_rp->bitmap_size);
/* Completely out of VM? */
if (index >= root_rp->bitmap_size) {
clib_warning("region %s: not enough VM to allocate 0x%x",
root_rp->region_name, a->size);
svm_pop_heap (oldheap);
region_unlock (root_rp);
return 0;
}
/*
* Mark virtual space allocated
*/
#if CLIB_DEBUG > 1
clib_warning ("set %d bits at index %d", need_nbits, index);
#endif
for (i = 0; i < need_nbits; i++) {
clib_bitmap_set_no_check (root_rp->bitmap, index+i, 1);
}
/* Place this region where it goes... */
a->baseva = root_rp->virtual_base + index*MMAP_PAGESIZE;
rp = svm_map_region (a);
pool_get (mp->subregions, subp);
name = format (0, "%s%c", a->name, 0);
subp->subregion_name = name;
hash_set_mem (mp->name_hash, name, subp - mp->subregions);
svm_pop_heap (oldheap);
region_unlock (root_rp);
return (rp);
}
/*
* svm_region_unmap
*
* Let go of the indicated region. If the calling process
* is the last customer, throw it away completely.
* The root region mutex guarantees atomicity with respect to
* a new region client showing up at the wrong moment.
*/
void svm_region_unmap (void *rp_arg)
{
int i, mypid = getpid();
int nclients_left;
void *oldheap;
uword virtual_base, virtual_size;
svm_region_t *rp = rp_arg;
char *name;
/*
* If we take a signal while holding one or more shared-memory
* mutexes, we may end up back here from an otherwise
* benign exit handler. Bail out to avoid a recursive
* mutex screw-up.
*/
if (nheld)
return;
ASSERT(rp);
ASSERT(root_rp);
if (CLIB_DEBUG > 1)
clib_warning ("[%d] unmap region %s", getpid(), rp->region_name);
region_lock (root_rp, 5);
region_lock (rp, 6);
oldheap = svm_push_pvt_heap (rp); /* nb vec_delete() in the loop */
/* Remove the caller from the list of mappers */
for (i = 0; i < vec_len(rp->client_pids); i++) {
if (rp->client_pids[i] == mypid) {
vec_delete (rp->client_pids, 1, i);
goto found;
}
}
clib_warning("pid %d AWOL", mypid);
found:
svm_pop_heap (oldheap);
nclients_left = vec_len(rp->client_pids);
virtual_base = rp->virtual_base;
virtual_size = rp->virtual_size;
if (nclients_left == 0) {
int index, nbits, i;
svm_main_region_t *mp;
uword *p;
svm_subregion_t *subp;
/* Kill the region, last guy on his way out */
oldheap = svm_push_pvt_heap (root_rp);
name = vec_dup (rp->region_name);
virtual_base = rp->virtual_base;
virtual_size = rp->virtual_size;
/* Figure out which bits to clear in the root region bitmap */
index = (virtual_base - root_rp->virtual_base)
/ MMAP_PAGESIZE;
nbits = (virtual_size + MMAP_PAGESIZE - 1)
/ MMAP_PAGESIZE;
#if CLIB_DEBUG > 1
clib_warning ("clear %d bits at index %d", nbits, index);
#endif
/* Give back the allocated VM */
for (i = 0; i < nbits; i++) {
clib_bitmap_set_no_check (root_rp->bitmap, index+i, 0);
}
mp = root_rp->data_base;
p = hash_get_mem (mp->name_hash, name);
/* Better never happen ... */
if (p == NULL) {
region_unlock (rp);
region_unlock (root_rp);
svm_pop_heap (oldheap);
clib_warning ("Region name '%s' not found?", name);
return;
}
/* Remove from the root region subregion pool */
subp = mp->subregions + p[0];
pool_put (mp->subregions, subp);
hash_unset_mem (mp->name_hash, name);
vec_free(name);
region_unlock (rp);
shm_unlink(rp->region_name);
munmap ((void *)virtual_base, virtual_size);
region_unlock (root_rp);
svm_pop_heap (oldheap);
return;
}
region_unlock(rp);
region_unlock(root_rp);
munmap ((void *)virtual_base, virtual_size);
}
/*
* svm_region_exit
* There is no clean way to unlink the
* root region when all clients go away,
* so remove the pid entry and call it a day.
*/
void svm_region_exit ()
{
void *oldheap;
int i, mypid = getpid();
uword virtual_base, virtual_size;
/* It felt so nice we did it twice... */
if (root_rp == 0)
return;
if (--root_rp_refcount > 0)
return;
/*
* If we take a signal while holding one or more shared-memory
* mutexes, we may end up back here from an otherwise
* benign exit handler. Bail out to avoid a recursive
* mutex screw-up.
*/
if (nheld)
return;
region_lock(root_rp, 7);
oldheap = svm_push_pvt_heap (root_rp);
virtual_base = root_rp->virtual_base;
virtual_size = root_rp->virtual_size;
for (i = 0; i < vec_len(root_rp->client_pids); i++) {
if (root_rp->client_pids[i] == mypid) {
vec_delete (root_rp->client_pids, 1, i);
goto found;
}
}
clib_warning("pid %d AWOL", mypid);
found:
region_unlock(root_rp);
svm_pop_heap (oldheap);
root_rp = 0;
munmap ((void *)virtual_base, virtual_size);
}
void svm_client_scan_this_region_nolock (svm_region_t *rp)
{
int j;
int mypid = getpid();
void *oldheap;
for (j = 0; j < vec_len(rp->client_pids); j++) {
if (mypid == rp->client_pids[j])
continue;
if (rp->client_pids[j] && (kill (rp->client_pids[j], 0) < 0)) {
clib_warning ("%s: cleanup ghost pid %d",
rp->region_name, rp->client_pids[j]);
/* nb: client vec in rp->region_heap */
oldheap = svm_push_pvt_heap (rp);
vec_delete (rp->client_pids, 1, j);
j--;
svm_pop_heap (oldheap);
}
}
}
/*
* Scan svm regions for dead clients
*/
void svm_client_scan(char *root_path)
{
int i, j;
svm_main_region_t *mp;
svm_map_region_args_t *a = 0;
svm_region_t *root_rp;
svm_region_t *rp;
svm_subregion_t *subp;
u8 *name=0;
u8 ** svm_names=0;
void *oldheap;
int mypid = getpid();
vec_validate (a, 0);
svm_region_init_chroot(root_path);
root_rp = svm_get_root_rp();
pthread_mutex_lock (&root_rp->mutex);
mp = root_rp->data_base;
for (j = 0; j < vec_len (root_rp->client_pids); j++) {
if (mypid == root_rp->client_pids[j])
continue;
if (root_rp->client_pids[j]
&& (kill (root_rp->client_pids[j], 0) < 0)) {
clib_warning ("%s: cleanup ghost pid %d",
root_rp->region_name, root_rp->client_pids[j]);
/* nb: client vec in root_rp->region_heap */
oldheap = svm_push_pvt_heap (root_rp);
vec_delete (root_rp->client_pids, 1, j);
j--;
svm_pop_heap (oldheap);
}
}
/*
* Snapshoot names, can't hold root rp mutex across
* find_or_create.
*/
pool_foreach (subp, mp->subregions, ({
name = vec_dup (subp->subregion_name);
vec_add1(svm_names, name);
}));
pthread_mutex_unlock (&root_rp->mutex);
for (i = 0; i < vec_len(svm_names); i++) {
vec_validate(a, 0);
a->root_path = root_path;
a->name = (char *) svm_names[i];
rp = svm_region_find_or_create (a);
if (rp) {
pthread_mutex_lock (&rp->mutex);
svm_client_scan_this_region_nolock (rp);
pthread_mutex_unlock (&rp->mutex);
svm_region_unmap (rp);
vec_free(svm_names[i]);
}
vec_free (a);
}
vec_free(svm_names);
svm_region_exit ();
vec_free (a);
}
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