extstore: pause compaction thread with hash expand

could potentially cause weirdness when the hash table is swapped.

3 files changed, 25 insertions, 0 deletions

diff --git a/storage.c b/storage.c
index eb0ea95..8a68bbe 100644
--- a/storage.c
+++ b/storage.c
@@ -177,6 +177,7 @@ static int storage_compact_check(void *storage, logger *l,
 }
 
 static pthread_t storage_compact_tid;
+static pthread_mutex_t storage_compact_plock;
 #define MIN_STORAGE_COMPACT_SLEEP 10000
 #define MAX_STORAGE_COMPACT_SLEEP 2000000
 
@@ -328,12 +329,15 @@ static void *storage_compact_thread(void *arg) {
     wrap.io.len = settings.ext_wbuf_size;
     wrap.io.mode = OBJ_IO_READ;
     wrap.io.cb = _storage_compact_cb;
+    pthread_mutex_lock(&storage_compact_plock);
 
     while (1) {
+        pthread_mutex_unlock(&storage_compact_plock);
         if (to_sleep) {
             extstore_run_maint(storage);
             usleep(to_sleep);
         }
+        pthread_mutex_lock(&storage_compact_plock);
 
         if (!compacting && storage_compact_check(storage, l,
                     &page_id, &page_version, &page_size, &drop_unread)) {
@@ -393,6 +397,7 @@ static void *storage_compact_thread(void *arg) {
 }
 
 // TODO
+// logger needs logger_destroy() to exist/work before this is safe.
 /*int stop_storage_compact_thread(void) {
     int ret;
     pthread_mutex_lock(&lru_maintainer_lock);
@@ -406,9 +411,18 @@ static void *storage_compact_thread(void *arg) {
     return 0;
 }*/
 
+void storage_compact_pause(void) {
+    pthread_mutex_lock(&storage_compact_plock);
+}
+
+void storage_compact_resume(void) {
+    pthread_mutex_unlock(&storage_compact_plock);
+}
+
 int start_storage_compact_thread(void *arg) {
     int ret;
 
+    pthread_mutex_init(&storage_compact_plock, NULL);
     if ((ret = pthread_create(&storage_compact_tid, NULL,
         storage_compact_thread, arg)) != 0) {
         fprintf(stderr, "Can't create storage_compact thread: %s\n",
diff --git a/storage.h b/storage.h
index 3bfeacc..7af6cc0 100644
--- a/storage.h
+++ b/storage.h
@@ -3,5 +3,7 @@
 
 int lru_maintainer_store(void *storage, const int clsid);
 int start_storage_compact_thread(void *arg);
+void storage_compact_pause(void);
+void storage_compact_resume(void);
 
 #endif
diff --git a/thread.c b/thread.c
index e9f40a6..df05d5f 100644
--- a/thread.c
+++ b/thread.c
@@ -3,6 +3,9 @@
  * Thread management for memcached.
  */
 #include "memcached.h"
+#ifdef EXTSTORE
+#include "storage.h"
+#endif
 #include <assert.h>
 #include <stdio.h>
 #include <errno.h>
@@ -139,6 +142,9 @@ void pause_threads(enum pause_thread_types type) {
             lru_maintainer_pause();
             slabs_rebalancer_pause();
             lru_crawler_pause();
+#ifdef EXTSTORE
+            storage_compact_pause();
+#endif
         case PAUSE_WORKER_THREADS:
             buf[0] = 'p';
             pthread_mutex_lock(&worker_hang_lock);
@@ -147,6 +153,9 @@ void pause_threads(enum pause_thread_types type) {
             lru_maintainer_resume();
             slabs_rebalancer_resume();
             lru_crawler_resume();
+#ifdef EXTSTORE
+            storage_compact_resume();
+#endif
         case RESUME_WORKER_THREADS:
             pthread_mutex_unlock(&worker_hang_lock);
             break;