From f65d46723cd0e2d3a9b1f788b0ffa51e7fd04f8b Mon Sep 17 00:00:00 2001
From: John Kacur <jkacur@redhat.com>
Date: Thu, 23 May 2019 17:54:20 +0200
Subject: [PATCH 1/2] rteval: Check whether a cpu is online before adding it to
 the list

Check whether a cpu is online before adding it to the list

If sys online files exist, use them to determine if a cpu is online

This is done in two places, misc.py, and also in systopology which is
getting the cpus from the numa node in /sys/devices, including offline
cpus

Signed-off-by: John Kacur <jkacur@redhat.com>
---
 rteval/misc.py        | 19 ++++++++++++++++++-
 rteval/systopology.py | 29 ++++++++++++++++++++++++-----
 2 files changed, 42 insertions(+), 6 deletions(-)

diff --git a/rteval/misc.py b/rteval/misc.py
index 7c9991483728..a43a8964e061 100644
--- a/rteval/misc.py
+++ b/rteval/misc.py
@@ -36,7 +36,24 @@ def expand_cpulist(cpulist):
     return [ str(i) for i in list(set(result)) ]
 
 def online_cpus():
-    return [ str(c.replace('/sys/devices/system/cpu/cpu', ''))  for c in glob.glob('/sys/devices/system/cpu/cpu[0-9]*') ]
+    online_cpus = []
+    # Check for the online file with cpu1 since cpu0 can't always be offlined
+    if os.path.exists('/sys/devices/system/cpu/cpu1/online'):
+        for c in glob.glob('/sys/devices/system/cpu/cpu[0-9]*'):
+            num = str(c.replace('/sys/devices/system/cpu/cpu',''))
+            # On some machine you can't turn off cpu0
+            if not os.path.exists(c + '/online') and num == "0":
+                online_cpus.append(num)
+            else:
+                with open(c + '/online') as f:
+                    is_online = f.read().rstrip('\n')
+                if is_online == "1":
+                    online_cpus.append(num)
+    else: # use the old heuristic
+        for c in glob.glob('/sys/devices/system/cpu/cpu[0-9]*'):
+            num = str(c.replace('/sys/devices/system/cpu/cpu',''))
+            online_cpus.append(num)
+    return online_cpus
 
 def invert_cpulist(cpulist):
     return [ c for c in online_cpus() if c not in cpulist]
diff --git a/rteval/systopology.py b/rteval/systopology.py
index 97a6037e83aa..07674658df8e 100644
--- a/rteval/systopology.py
+++ b/rteval/systopology.py
@@ -45,6 +45,7 @@ class CpuList(object):
             self.cpulist = cpulist
         elif type(cpulist) is str:
             self.cpulist = self.__expand_cpulist(cpulist)
+        self.cpulist = self.online_cpulist(self.cpulist)
         self.cpulist.sort()
 
     def __str__(self):
@@ -56,6 +57,10 @@ class CpuList(object):
     def __len__(self):
         return len(self.cpulist)
 
+    def online_file_exists(self):
+        if os.path.exists('/sys/devices/system/cpu/cpu1/online'):
+            return True
+        return False
 
     # return the index of the last element of a sequence
     # that steps by one
@@ -68,7 +73,6 @@ class CpuList(object):
                 return idx
         return lim - 1
 
-
     #
     # collapse a list of cpu numbers into a string range
     # of cpus (e.g. 0-5, 7, 9)
@@ -110,15 +114,30 @@ class CpuList(object):
         return self.cpulist
 
     # check whether cpu n is online
-    def isonline(self, n):
+    def is_online(self, n):
         if n not in self.cpulist:
             raise RuntimeError("invalid cpu number %d" % n)
         if n == 0:
             return True
         path = os.path.join(CpuList.cpupath,'cpu%d' % n)
-        if os.path.exists(path):
-            return sysread(path, "online") == 1
-        return False
+        # Some hardware doesn't allow cpu0 to be turned off
+        if not os.path.exists(path + '/online') and n == 0:
+            return True
+        else:
+            return sysread(path, "online") == "1"
+
+    # Given a cpulist, return a cpulist of online cpus
+    def online_cpulist(self, cpulist):
+        # This only works if the sys online files exist
+        if not self.online_file_exists():
+            return cpulist
+        newlist = []
+        for cpu in cpulist:
+            if not self.online_file_exists() and cpu == '0':
+                newlist.append(cpu)
+            elif self.is_online(int(cpu)):
+                newlist.append(cpu)
+        return newlist
 
 #
 # class to abstract access to NUMA nodes in /sys filesystem
-- 
2.20.1