net/openvswitch/patches/0010-lib-ovs-thread-Ensure-that-thread-stacks-are-always-.patch

   1 From 8147cec9ee8feea9440cf79365709ddc32ff57d5 Mon Sep 17 00:00:00 2001
   2 From: Alexandru Ardelean <ardeleanalex@gmail.com>
   3 Date: Thu, 4 Feb 2016 09:20:34 +0200
   4 Subject: [PATCH] lib/ovs-thread: Ensure that thread stacks are always at least
   5  512 kB.
   6
   7 This makes a difference for libc implementations (such as musl libc) that
   8 have a really small default pthread stack size.
   9
  10 Will reference this discussion:
  11 http://patchwork.ozlabs.org/patch/572340/
  12
  13 Reported-by: Robert McKay <robert@mckay.com>
  14 Signed-off-by: Alexandru Ardelean <ardeleanalex@gmail.com>
  15 [blp@ovn.org made style changes]
  16 Signed-off-by: Ben Pfaff <blp@ovn.org>
  17 ---
  18  lib/ovs-thread.c | 29 +++++++++++++++++++++++++++++
  19  1 file changed, 29 insertions(+)
  20
  21 diff --git a/lib/ovs-thread.c b/lib/ovs-thread.c
  22 index 6ebda07..b0e10ee 100644
  23 --- a/lib/ovs-thread.c
  24 +++ b/lib/ovs-thread.c
  25 @@ -340,6 +340,25 @@ ovsthread_wrapper(void *aux_)
  26      return aux.start(aux.arg);
  27  }
  28
  29 +static void
  30 +set_min_stack_size(pthread_attr_t *attr, size_t min_stacksize)
  31 +{
  32 +    size_t stacksize;
  33 +    int error;
  34 +
  35 +    error = pthread_attr_getstacksize(attr, &stacksize);
  36 +    if (error) {
  37 +        ovs_abort(error, "pthread_attr_getstacksize failed");
  38 +    }
  39 +
  40 +    if (stacksize < min_stacksize) {
  41 +        error = pthread_attr_setstacksize(attr, min_stacksize);
  42 +        if (error) {
  43 +            ovs_abort(error, "pthread_attr_setstacksize failed");
  44 +        }
  45 +    }
  46 +}
  47 +
  48  /* Starts a thread that calls 'start(arg)'.  Sets the thread's name to 'name'
  49   * (suffixed by its ovsthread_id()).  Returns the new thread's pthread_t. */
  50  pthread_t
  51 @@ -358,10 +377,20 @@ ovs_thread_create(const char *name, void *(*start)(void *), void *arg)
  52      aux->arg = arg;
  53      ovs_strlcpy(aux->name, name, sizeof aux->name);
  54
  55 -    error = pthread_create(&thread, NULL, ovsthread_wrapper, aux);
  56 +    /* Some small systems use a default stack size as small as 80 kB, but OVS
  57 +     * requires approximately 384 kB according to the following analysis:
  58 +     * http://openvswitch.org/pipermail/dev/2016-January/065049.html
  59 +     *
  60 +     * We use 512 kB to give us some margin of error. */
  61 +    pthread_attr_t attr;
  62 +    pthread_attr_init(&attr);
  63 +    set_min_stack_size(&attr, 512 * 1024);
  64 +
  65 +    error = pthread_create(&thread, &attr, ovsthread_wrapper, aux);
  66      if (error) {
  67          ovs_abort(error, "pthread_create failed");
  68      }
  69 +    pthread_attr_destroy(&attr);
  70      return thread;
  71  }
  72  \f
  73 --
  74 2.1.4
  75