From: Amaury Denoyelle <adenoyelle@haproxy.com>
Date: Wed, 31 Mar 2021 14:57:39 +0000 (+0200)
Subject: MINOR: thread: implement the detection of forced cpu affinity
X-Git-Tag: v2.4-dev17~14
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4c9efdecf5aa3d4cca1a325ac1d98cfba01bcf83;p=thirdparty%2Fhaproxy.git

MINOR: thread: implement the detection of forced cpu affinity

Create a function thread_cpu_mask_forced. Its purpose is to report if a
restrictive cpu mask is active for the current proces, for example due
to a taskset invocation. It is only implemented for the linux platform
currently.
---

diff --git a/include/haproxy/thread.h b/include/haproxy/thread.h
index e7d6d2cba2..6a4b400f87 100644
--- a/include/haproxy/thread.h
+++ b/include/haproxy/thread.h
@@ -277,6 +277,10 @@ static inline unsigned long thread_isolated()
 	return threads_want_rdv_mask & ~threads_harmless_mask & tid_bit;
 }
 
+/* Returns 1 if the cpu set is currently restricted for the process else 0.
+ * Currently only implemented for the Linux platform.
+ */
+int thread_cpu_mask_forced();
 
 #if !defined(DEBUG_THREAD) && !defined(DEBUG_FULL)
 
diff --git a/src/thread.c b/src/thread.c
index 07017dd189..fd9e6b632e 100644
--- a/src/thread.c
+++ b/src/thread.c
@@ -193,6 +193,19 @@ static int thread_cpus_enabled()
 	return ret;
 }
 
+/* Returns 1 if the cpu set is currently restricted for the process else 0.
+ * Currently only implemented for the Linux platform.
+ */
+int thread_cpu_mask_forced()
+{
+#if defined(__linux__)
+	const int cpus_avail = sysconf(_SC_NPROCESSORS_ONLN);
+	return cpus_avail != thread_cpus_enabled();
+#else
+	return 0;
+#endif
+}
+
 /* Depending on the platform and how libpthread was built, pthread_exit() may
  * involve some code in libgcc_s that would be loaded on exit for the first
  * time, causing aborts if the process is chrooted. It's harmless bit very