From 40939c6b2ef877a46fa0b3ec177673e6b0831414 Mon Sep 17 00:00:00 2001
Message-Id: <40939c6b2ef877a46fa0b3ec177673e6b0831414@dist-git>
From: Andrea Bolognani <abologna@redhat.com>
Date: Wed, 5 Aug 2015 18:18:30 +0200
Subject: [PATCH] nodeinfo: Use a bitmap to keep track of node CPUs

Keep track of what CPUs belong to the current node while walking
through the sysfs node entry, so we don't need to do it a second
time immediately afterwards.

This also allows us to loop through all CPUs that are part of a
node in guaranteed ascending order, which is something that is
required for some upcoming changes.

(cherry picked from commit 05be6062822f3f694b9e2ba1982d60cad5c09f33)

Bug: https://bugzilla.redhat.com/show_bug.cgi?id=1213713

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
---
 src/nodeinfo.c | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/src/nodeinfo.c b/src/nodeinfo.c
index 2d910c9..2328a86 100644
--- a/src/nodeinfo.c
+++ b/src/nodeinfo.c
@@ -410,8 +410,10 @@ virNodeParseNode(const char *sysfs_prefix,
     struct dirent *cpudirent = NULL;
     virBitmapPtr present_cpumap = NULL;
     virBitmapPtr online_cpus_map = NULL;
+    virBitmapPtr node_cpus_map = NULL;
     virBitmapPtr sockets_map = NULL;
     virBitmapPtr *cores_maps = NULL;
+    int npresent_cpus;
     int sock_max = 0;
     int sock;
     int core;
@@ -436,6 +438,12 @@ virNodeParseNode(const char *sysfs_prefix,
     if (!online_cpus_map)
         goto cleanup;
 
+    npresent_cpus = virBitmapSize(present_cpumap);
+
+    /* Keep track of the CPUs that belong to the current node */
+    if (!(node_cpus_map = virBitmapNew(npresent_cpus)))
+        goto cleanup;
+
     /* enumerate sockets in the node */
     if (!(sockets_map = virBitmapNew(ID_MAX + 1)))
         goto cleanup;
@@ -447,6 +455,10 @@ virNodeParseNode(const char *sysfs_prefix,
         if (!virBitmapIsBitSet(present_cpumap, cpu))
             continue;
 
+        /* Mark this CPU as part of the current node */
+        if (virBitmapSetBit(node_cpus_map, cpu) < 0)
+            goto cleanup;
+
         if (!virBitmapIsBitSet(online_cpus_map, cpu))
             continue;
 
@@ -480,13 +492,11 @@ virNodeParseNode(const char *sysfs_prefix,
         if (!(cores_maps[i] = virBitmapNew(ID_MAX + 1)))
             goto cleanup;
 
-    /* iterate over all CPU's in the node */
-    rewinddir(cpudir);
-    while ((direrr = virDirRead(cpudir, &cpudirent, node)) > 0) {
-        if (sscanf(cpudirent->d_name, "cpu%u", &cpu) != 1)
-            continue;
+    /* Iterate over all CPUs in the node, in ascending order */
+    for (cpu = 0; cpu < npresent_cpus; cpu++) {
 
-        if (!virBitmapIsBitSet(present_cpumap, cpu))
+        /* Skip CPUs that are not part of the current node */
+        if (!virBitmapIsBitSet(node_cpus_map, cpu))
             continue;
 
         if (!virBitmapIsBitSet(online_cpus_map, cpu)) {
@@ -529,9 +539,6 @@ virNodeParseNode(const char *sysfs_prefix,
             *threads = siblings;
     }
 
-    if (direrr < 0)
-        goto cleanup;
-
     /* finalize the returned data */
     *sockets = virBitmapCountBits(sockets_map);
 
@@ -557,6 +564,7 @@ virNodeParseNode(const char *sysfs_prefix,
             virBitmapFree(cores_maps[i]);
     VIR_FREE(cores_maps);
     virBitmapFree(sockets_map);
+    virBitmapFree(node_cpus_map);
     virBitmapFree(online_cpus_map);
     virBitmapFree(present_cpumap);
 
-- 
2.5.0