Split the worker thread workspace size out into its own parameter

"thread_pool_workspace"

bin/varnishd/cache_pool.c

@@ -123,6 +123,7 @@ wrk_thread_real(struct wq *qp, unsigned shm_workspace, unsigned sess_workspace,
 {
 	struct worker *w, ww;
 	uint32_t wlog[shm_workspace / 4];
+	/* XXX: can we trust these to be properly aligned ? */
 	unsigned char ws[sess_workspace];
 	unsigned char http0[http_space];
 	unsigned char http1[http_space];
@@ -230,7 +231,7 @@ wrk_thread(void *priv)
 		siov = IOV_MAX;
 	return (wrk_thread_real(qp,
 	    params->shm_workspace,
-	    params->sess_workspace,
+	    params->wthread_workspace,
 	    nhttp, HTTP_estimate(nhttp), siov));
 }
 

bin/varnishd/heritage.h

@@ -90,6 +90,7 @@ struct params {
 	unsigned		wthread_purge_delay;
 	unsigned		wthread_stats_rate;
 	unsigned		wthread_stacksize;
+	unsigned		wthread_workspace;
 
 	unsigned		queue_max;
 

bin/varnishd/mgt_pool.c

@@ -227,5 +227,16 @@ const struct parspec WRK_parspec[] = {
 		"many threads into the limited address space.\n",
 		EXPERIMENTAL,
 		"-1", "bytes" },
+	{ "thread_pool_workspace", tweak_uint, &master.wthread_workspace,
+		1024, UINT_MAX,
+		"Bytes of HTTP protocol workspace allocated for worker "
+		"threads. "
+		"This space must be big enough for the backend request "
+		"and responses, and response to the client plus any other "
+		"memory needs in the VCL code."
+		"Minimum is 1024 bytes.",
+		DELAYED_EFFECT,
+		"65536",
+		"bytes" },
 	{ NULL, NULL, NULL }
 };