zhuyijun/read-redis
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removed a few races from threaded VM

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antirez 2010-01-15 05:09:18 -05:00
parent 2e111efe5a
commit 1064ef8764
2 changed files with 16 additions and 4 deletions
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3
TODO
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@ -16,9 +16,8 @@ Virtual Memory sub-TODO:
* Divide swappability of objects by refcount
* vm-swap-file <filename>. The swap file should go where the user wants, and if it's already there and of the right size we can avoid to create it again.
* it should be possible to give the vm-max-memory option in megabyte, gigabyte, ..., just using 2GB, 100MB, and so forth.
* Make sure to wait all the IO threads are done before to fork() for BGSAVE and BGREWRITEAOF
* Enlarge the stack of threads, to problems when calling LZF lib.
* redis-cli vmstat, calling INFO every second and printing VM stats ala vmstat.
* protect zmalloc memory usage increments with a mutex
VERSION 1.6 TODO (Virtual memory)
=================================

17
redis.c
View File

@ -2419,6 +2419,10 @@ static robj *createObject(int type, void *ptr) {
o->ptr = ptr;
o->refcount = 1;
if (server.vm_enabled) {
/* Note that this code may run in the context of an I/O thread
* and accessing to server.unixtime in theory is an error
* (no locks). But in practice this is safe, and even if we read
* garbage Redis will not fail, as it's just a statistical info */
o->vm.atime = server.unixtime;
o->storage = REDIS_VM_MEMORY;
}
@ -5631,6 +5635,7 @@ static sds genRedisInfoString(void) {
);
}
if (server.vm_enabled) {
lockThreadedIO();
info = sdscatprintf(info,
"vm_conf_max_memory:%llu\r\n"
"vm_conf_page_size:%llu\r\n"
@ -5657,6 +5662,7 @@ static sds genRedisInfoString(void) {
(unsigned long) listLength(server.io_clients),
(unsigned long) server.io_active_threads
);
unlockThreadedIO();
}
for (j = 0; j < server.dbnum; j++) {
long long keys, vkeys;
@ -7355,7 +7361,14 @@ static int vmSwapOneObject(int usethreads) {
de = dictGetRandomKey(db->dict);
key = dictGetEntryKey(de);
val = dictGetEntryVal(de);
if (key->storage != REDIS_VM_MEMORY) {
/* Only swap objects that are currently in memory.
*
* Also don't swap shared objects if threaded VM is on, as we
* try to ensure that the main thread does not touch the
* object while the I/O thread is using it, but we can't
* control other keys without adding additional mutex. */
if (key->storage != REDIS_VM_MEMORY ||
(server.vm_max_threads != 0 && val->refcount != 1)) {
if (maxtries) i--; /* don't count this try */
continue;
}
@ -7457,10 +7470,10 @@ static void vmThreadedIOCompletedJob(aeEventLoop *el, int fd, void *privdata,
struct dictEntry *de;
redisLog(REDIS_DEBUG,"Processing I/O completed job");
assert(listLength(server.io_processed) != 0);
/* Get the processed element (the oldest one) */
lockThreadedIO();
assert(listLength(server.io_processed) != 0);
ln = listFirst(server.io_processed);
j = ln->value;
listDelNode(server.io_processed,ln);