new file mode 100644
--- /dev/null
+++ b/src/core/ngx_slab.c
@@ -0,0 +1,8 @@
+
+
+void *ngx_slab_alloc(ngx_slab_pool_t *pool, size_t size)
+{
+
+
+   return NULL;
+}

new file mode 100644
--- /dev/null
+++ b/src/core/ngx_slab.h
@@ -0,0 +1,37 @@
+#ifndef _NGX_SLAB_H_INCLUDED_
+#define _NGX_SLAB_H_INCLUDED_
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+
+
+typedef struct ngx_free_slab_s  ngx_free_slab_t;
+
+typedef struct ngx_free_slab_s {
+    ngx_free_slab_t  *next;
+}
+
+
+typedef struct ngx_slab_block_s  ngx_slab_block_t;
+
+typedef struct ngx_slab_block_s {
+    ngx_free_slab_t  *free;
+    ngx_slab_buf_t   *next;
+    size_t            color;
+};
+
+
+typedef struct {
+    ngx_slab_buf_t   *blocks;
+    size_t            size;
+
+    void             *start;
+    uint32_t          map;
+
+    ngx_log_t        *log;
+    ngx_free_pool_t   free;
+} ngx_slab_pool_t;
+
+
+#endif /* _NGX_SLAB_H_INCLUDED_ */

--- a/src/os/unix/ngx_process_cycle.c
+++ b/src/os/unix/ngx_process_cycle.c
@@ -655,12 +655,19 @@ static void ngx_channel_handler(ngx_even
 
     c = ev->data;
 
+    ngx_log_debug0(NGX_LOG_DEBUG_CORE, ev->log, 0, "channel handler");
+
     n = ngx_read_channel(c->fd, &ch, sizeof(ngx_channel_t), ev->log);
 
+    ngx_log_debug1(NGX_LOG_DEBUG_CORE, ev->log, 0, "channel: %d", n);
+
     if (n <= 0) {
         return;
     }
 
+    ngx_log_debug1(NGX_LOG_DEBUG_CORE, ev->log, 0,
+                   "channel command: %d", ch.command);
+
     switch (ch.command) {
 
     case NGX_CMD_QUIT: