Re: [PATCH 1/2] util: split the virNumaGetHugePageInfoPath into separate function

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Sorry for the delay, i just came back from a long holiday.


On 10/02/2015 11:49 PM, John Ferlan wrote:

On 09/30/2015 12:01 AM, Luyao Huang wrote:
https://bugzilla.redhat.com/show_bug.cgi?id=1265114

When pass 0 page_size to virNumaGetHugePageInfoPath function, we will
get fail like this:

  error : virFileReadAll:1358 : Failed to read file '/sys/devices/system/node/node0/hugepages/': Is a directory

Because when the page_size is 0 the virNumaGetHugePageInfoPath will
build the directory of system path, but we don't want that.

Introduce a new helper to build the dir path could avoid this issue.

This appears to be just a straight refactor - it took me a while to
figure out why the key was 'page_size == 0'. Looking at "just" this
context it would seem virNumaGetPages using 0 && suffix==NULL was the
only user/cause for this.  But the real abuser/issue shows up in patch 2
where if "other" callers use a page_size == 0, then we have issues.

So, how about the following for a commit message:

Refactor virNumaGetHugePageInfoPath to handle the passing a page_size
of 0 and suffix == NULL into a new function virNumaGetHugePageInfoDir.
Function virNumaGetPages expects to return a directory; whereas, other
callers that passed a page_size == 0 would not expect a directory
path in return. Each of those callers will use virFileReadAll which
fails if a directory path is returned as follows:

     error : virFileReadAll:1358 : Failed to read file
             '/sys/devices/system/node/node0/hugepages/': Is a directory



Looks good to me, thanks a lot for your help.

Signed-off-by: Luyao Huang <lhuang@xxxxxxxxxx>
---
  src/util/virnuma.c | 42 ++++++++++++++++++------------------------
  1 file changed, 18 insertions(+), 24 deletions(-)

diff --git a/src/util/virnuma.c b/src/util/virnuma.c
index 1a62d62..8577bd8 100644
--- a/src/util/virnuma.c
+++ b/src/util/virnuma.c
@@ -493,45 +493,39 @@ virNumaGetHugePageInfoPath(char **path,
                             unsigned int page_size,
                             const char *suffix)
  {
-
-    int ret = -1;
-
      if (node == -1) {
          /* We are aiming at overall system info */
-        if (page_size) {
-            /* And even on specific huge page size */
              if (virAsprintf(path,
                              HUGEPAGES_SYSTEM_PREFIX HUGEPAGES_PREFIX "%ukB/%s",
                              page_size, suffix ? suffix : "") < 0)
Now this has too many spaces shifted to the right (4 to be exact)

Indeed, i forgot this during wrote this patch.

-                goto cleanup;
-        } else {
-            if (VIR_STRDUP(*path, HUGEPAGES_SYSTEM_PREFIX) < 0)
-                goto cleanup;
-        }
-
+                return -1;
      } else {
          /* We are aiming on specific NUMA node */
-        if (page_size) {
-            /* And even on specific huge page size */
              if (virAsprintf(path,
                              HUGEPAGES_NUMA_PREFIX "node%d/hugepages/"
                              HUGEPAGES_PREFIX "%ukB/%s",
                              node, page_size, suffix ? suffix : "") < 0)
same note here

-                goto cleanup;
-        } else {
-            if (virAsprintf(path,
-                            HUGEPAGES_NUMA_PREFIX "node%d/hugepages/",
-                            node) < 0)
-                goto cleanup;
-        }
+                return -1;
      }
- ret = 0;
- cleanup:
-    return ret;
+    return 0;
  }
+static int
+virNumaGetHugePageInfoDir(char **path, int node)
+{
+    if (node == -1) {
+        if (VIR_STRDUP(*path, HUGEPAGES_SYSTEM_PREFIX) < 0)
+            return -1;
+    } else {
+        if (virAsprintf(path,
+                        HUGEPAGES_NUMA_PREFIX "node%d/hugepages/",
+                        node) < 0)
+            return -1;
Even more optimization could be to just return VIR_STRDUP or virAsprintf
result.

Similarly the virNumaGetHugePageInfoPath can have the same change - that
is return directly from virAsprintf commands.

Right, i missed this, thanks for pointing out that.

I can adjust the commit message and nits - just let me know if the new
commit message reads better.

The new commit message is better, thanks a lot for your review and help !

John

+    }
+ return 0;
+}
  /**
   * virNumaGetHugePageInfo:
   * @node: NUMA node id
@@ -724,7 +718,7 @@ virNumaGetPages(int node,
       * is always shown as used memory. Here, however, we want to report
       * slightly different information. So we take the total memory on a node
       * and subtract memory taken by the huge pages. */
-    if (virNumaGetHugePageInfoPath(&path, node, 0, NULL) < 0)
+    if (virNumaGetHugePageInfoDir(&path, node) < 0)
          goto cleanup;
if (!(dir = opendir(path))) {


Luyao

--
libvir-list mailing list
libvir-list@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/libvir-list



[Index of Archives]     [Virt Tools]     [Libvirt Users]     [Lib OS Info]     [Fedora Users]     [Fedora Desktop]     [Fedora SELinux]     [Big List of Linux Books]     [Yosemite News]     [KDE Users]     [Fedora Tools]