Stored pages release routine

2 files changed, 33 insertions, 0 deletions

diff --git a/sysdep/unix/alloc.c b/sysdep/unix/alloc.c
index 4ae1a9db..61360e73 100644
--- a/sysdep/unix/alloc.c
+++ b/sysdep/unix/alloc.c
@@ -135,3 +135,32 @@ free_sys_page(void *ptr)
 #endif
     free(ptr);
 }
+
+void
+check_stored_pages(void)
+{
+#ifdef ENOMEM
+  if (atomic_load_explicit(&global_page_list_not_empty, memory_order_relaxed) == 0)
+    return;
+
+  for (uint limit = 0; limit < 256; limit++)
+  {
+    GLOBAL_PAGE_SPIN_LOCK;
+    void *ptr = HEAD(global_page_list);
+    if (!NODE_VALID(ptr))
+    {
+      atomic_store_explicit(&global_page_list_not_empty, 0, memory_order_relaxed);
+      GLOBAL_PAGE_SPIN_UNLOCK;
+      return;
+    }
+
+    rem_node(ptr);
+    if (munmap(ptr, page_size) < 0)
+      if (errno == ENOMEM)
+	add_tail(&global_page_list, ptr);
+      else
+	bug("munmap(%p) failed: %m", ptr);
+    GLOBAL_PAGE_SPIN_UNLOCK;
+  }
+#endif
+}
diff --git a/sysdep/unix/io.c b/sysdep/unix/io.c
index dd385c80..91d717d0 100644
--- a/sysdep/unix/io.c
+++ b/sysdep/unix/io.c
@@ -2193,6 +2193,7 @@ static int short_loops = 0;
 #define WORK_EVENTS_MAX 10
 
 void pipe_drain(int fd);
+void check_stored_pages(void);
 
 void
 io_loop(void)
@@ -2215,6 +2216,9 @@ io_loop(void)
       timers_fire(&main_birdloop.time, 1);
       io_close_event();
 
+      /* Try to release some memory if possible */
+      check_stored_pages();
+
       // FIXME
       poll_tout = (events ? 0 : 3000); /* Time in milliseconds */
       if (t = timers_first(&main_birdloop.time))