[libvirt] [PATCH v3 1/2] process: wait longer on kill per assigned Hostdev

[Christian Ehrhardt]

It was found that in cases with host devices virProcessKillPainfully
might be able to send signal zero to the target PID for quite a while
with the process already being gone from /proc/<PID>.

That is due to cleanup and reset of devices which might include a
secondary bus reset that on top of the actions taken has a 1s delay
to let the bus settle. Due to that guests with plenty of Host devices
could easily exceed the default timeouts.

To solve that, this adds an extra delay of 2s per hostdev that is associated
to a VM.

Signed-off-by: Christian Ehrhardt <christian.ehrhardt at canonical.com>
---
 src/libvirt_private.syms |  1 +
 src/qemu/qemu_process.c  |  5 +++--
 src/util/virprocess.c    | 18 +++++++++++++++---
 src/util/virprocess.h    |  1 +
 4 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index ca4a192a4a..47ea35f864 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -2605,6 +2605,7 @@ virProcessGetPids;
 virProcessGetStartTime;
 virProcessKill;
 virProcessKillPainfully;
+virProcessKillPainfullyDelay;
 virProcessNamespaceAvailable;
 virProcessRunInMountNamespace;
 virProcessSchedPolicyTypeFromString;
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 02fdc55156..b7bf8813da 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -6814,8 +6814,9 @@ qemuProcessKill(virDomainObjPtr vm, unsigned int flags)
         return 0;
     }
 
-    ret = virProcessKillPainfully(vm->pid,
-                                  !!(flags & VIR_QEMU_PROCESS_KILL_FORCE));
+    ret = virProcessKillPainfullyDelay(vm->pid,
+                                       !!(flags & VIR_QEMU_PROCESS_KILL_FORCE),
+                                       vm->def->nhostdevs * 2);
 
     return ret;
 }
diff --git a/src/util/virprocess.c b/src/util/virprocess.c
index ecea27a2d4..46360cc051 100644
--- a/src/util/virprocess.c
+++ b/src/util/virprocess.c
@@ -341,15 +341,19 @@ int virProcessKill(pid_t pid, int sig)
  * Returns 0 if it was killed gracefully, 1 if it
  * was killed forcibly, -1 if it is still alive,
  * or another error occurred.
+ *
+ * Callers can proide an extra delay to wait longer
+ * than the default.
  */
 int
-virProcessKillPainfully(pid_t pid, bool force)
+virProcessKillPainfullyDelay(pid_t pid, bool force, unsigned int extradelay)
 {
     size_t i;
     int ret = -1;
+    unsigned int delay = 75 + (extradelay*5);
     const char *signame = "TERM";
 
-    VIR_DEBUG("vpid=%lld force=%d", (long long)pid, force);
+    VIR_DEBUG("vpid=%lld force=%d delay=%u", (long long)pid, force, pid);
 
     /* This loop sends SIGTERM, then waits a few iterations (10 seconds)
      * to see if it dies. If the process still hasn't exited, and
@@ -357,9 +361,12 @@ virProcessKillPainfully(pid_t pid, bool force)
      * wait up to 5 seconds more for the process to exit before
      * returning.
      *
+     * An extra delay can be specified for cases that are expected to clean
+     * up slower than usual.
+     *
      * Note that setting @force could result in dataloss for the process.
      */
-    for (i = 0; i < 75; i++) {
+    for (i = 0; i < delay; i++) {
         int signum;
         if (i == 0) {
             signum = SIGTERM; /* kindly suggest it should exit */
@@ -402,6 +409,11 @@ virProcessKillPainfully(pid_t pid, bool force)
 }
 
 
+int virProcessKillPainfully(pid_t pid, bool force)
+{
+    return virProcessKillPainfullyDelay(pid, force, 0);
+}
+
 #if HAVE_SCHED_GETAFFINITY
 
 int virProcessSetAffinity(pid_t pid, virBitmapPtr map)
diff --git a/src/util/virprocess.h b/src/util/virprocess.h
index 3c5a882772..b72603ca8e 100644
--- a/src/util/virprocess.h
+++ b/src/util/virprocess.h
@@ -55,6 +55,7 @@ virProcessWait(pid_t pid, int *exitstatus, bool raw)
 int virProcessKill(pid_t pid, int sig);
 
 int virProcessKillPainfully(pid_t pid, bool force);
+int virProcessKillPainfullyDelay(pid_t pid, bool force, unsigned int);
 
 int virProcessSetAffinity(pid_t pid, virBitmapPtr map);
 
-- 
2.17.1