xenpaging: implement stopping of pager by sending SIGTERM/SIGINT

Write all paged-out pages back into the guest if the pager is
interrupted by ctrl-c or if it receives SIGTERM.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Committed-by: Ian Jackson <ian.jackson.citrix.com>

1 files changed, 68 insertions, 0 deletions

diff --git a/tools/xenpaging/pagein.c b/tools/xenpaging/pagein.c
new file mode 100644
index 0000000000..93552c0bfa
--- /dev/null
+++ b/tools/xenpaging/pagein.c
@@ -0,0 +1,68 @@
+/* Trigger a page-in in a separate thread-of-execution to avoid deadlock */
+#include <pthread.h>
+#include "xc_private.h"
+
+struct page_in_args {
+    domid_t dom;
+    xc_interface *xch;
+};
+
+static struct page_in_args page_in_args;
+static unsigned long page_in_gfn;
+static unsigned int page_in_possible;
+
+static pthread_t page_in_thread;
+static pthread_cond_t page_in_cond = PTHREAD_COND_INITIALIZER;
+static pthread_mutex_t page_in_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+static void *page_in(void *arg)
+{
+    struct page_in_args *pia = arg;
+    void *page;
+    xen_pfn_t gfn;
+
+    while (1)
+    {
+        pthread_mutex_lock(&page_in_mutex);
+        while (!page_in_gfn)
+            pthread_cond_wait(&page_in_cond, &page_in_mutex);
+        gfn = page_in_gfn;
+        page_in_gfn = 0;
+        pthread_mutex_unlock(&page_in_mutex);
+
+        /* Ignore errors */
+        page = xc_map_foreign_pages(pia->xch, pia->dom, PROT_READ, &gfn, 1);
+        if (page)
+            munmap(page, PAGE_SIZE);
+    }
+    page_in_possible = 0;
+    pthread_exit(NULL);
+}
+
+void page_in_trigger(unsigned long gfn)
+{
+    if (!page_in_possible)
+        return;
+
+    pthread_mutex_lock(&page_in_mutex);
+    page_in_gfn = gfn;
+    pthread_mutex_unlock(&page_in_mutex);
+    pthread_cond_signal(&page_in_cond);
+}
+
+void create_page_in_thread(domid_t domain_id, xc_interface *xch)
+{
+    page_in_args.dom = domain_id;
+    page_in_args.xch = xch;
+    if (pthread_create(&page_in_thread, NULL, page_in, &page_in_args) == 0)
+        page_in_possible = 1;
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-set-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End: 
+ */