[Xen-changelog] [xen-4.1-testing] libxc: Replace malloc with alloca in hot path

[Xen patchbot-4.1-testing <patchbot@xxxxxxx>]

# HG changeset patch
# User Santosh Jodh <santosh.jodh@xxxxxxxxxx>
# Date 1331113150 0
# Node ID b7efb9e1a041f46baa9816025d8bf33dd1976db8
# Parent  1f95b55ef427144fc32759445791037f6b2c358d
libxc: Replace malloc with alloca in hot path

Replace malloc with alloc in hot paths for improved performance.

Signed-off-by: Santosh Jodh <santosh.jodh@xxxxxxxxxx>
Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Committed-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
xen-unstable changeset:   24709:8ba7ae0b070b
xen-unstable date:        Tue Feb 07 18:46:50 2012 +0000
---


diff -r 1f95b55ef427 -r b7efb9e1a041 tools/libxc/xc_linux_osdep.c
--- a/tools/libxc/xc_linux_osdep.c      Wed Mar 07 09:34:26 2012 +0000
+++ b/tools/libxc/xc_linux_osdep.c      Wed Mar 07 09:39:10 2012 +0000
@@ -218,7 +218,7 @@
          * IOCTL_PRIVCMD_MMAPBATCH_V2 is not supported - fall back to
          * IOCTL_PRIVCMD_MMAPBATCH.
          */
-        xen_pfn_t *pfn = malloc(num * sizeof(*pfn));
+        xen_pfn_t *pfn = alloca(num * sizeof(*pfn));
 
         if ( pfn )
         {
@@ -264,8 +264,6 @@
                 break;
             }
 
-            free(pfn);
-
             if ( rc == -ENOENT && i == num )
                 rc = 0;
             else if ( rc )
@@ -532,7 +530,7 @@
     void *addr = NULL;
     int i;
 
-    map = malloc(sizeof(*map) +
+    map = alloca(sizeof(*map) +
                  (count - 1) * sizeof(struct ioctl_gntdev_map_grant_ref));
     if ( map == NULL )
         return NULL;
@@ -567,7 +565,6 @@
     }
 
  out:
-    free(map);
 
     return addr;
 }

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