split storage writer into its own thread

trying out a simplified slab class backoff algorithm. The LRU maintainer
individually schedules slab classes by time, which leads to multiple wakeups
in a steady state as they get out of sync. This algorithm more simply skips
that class more often each time it runs the main loop, using a single
scheduled sleep instead.

if it goes to sleep for a long time, it also reduces the backoff for all
classes. if we're barely awake it should be fine to poke everything.

1 files changed, 2 insertions, 0 deletions

diff --git a/thread.c b/thread.c
index fb627b6..618ffac 100644
--- a/thread.c
+++ b/thread.c
@@ -144,6 +144,7 @@ void pause_threads(enum pause_thread_types type) {
             lru_crawler_pause();
 #ifdef EXTSTORE
             storage_compact_pause();
+            storage_write_pause();
 #endif
         case PAUSE_WORKER_THREADS:
             buf[0] = 'p';
@@ -155,6 +156,7 @@ void pause_threads(enum pause_thread_types type) {
             lru_crawler_resume();
 #ifdef EXTSTORE
             storage_compact_resume();
+            storage_write_resume();
 #endif
         case RESUME_WORKER_THREADS:
             pthread_mutex_unlock(&worker_hang_lock);