From 93ad7365e400915e6ce7fe6896ca7b599e7cf83a Mon Sep 17 00:00:00 2001
From: Richard Jones <rjones@redhat.com>
Date: Fri, 8 May 2009 08:44:34 +0100
Subject: [PATCH] Change memory calculation to choose a generous amount of
 memory.

---
 src/guestfs.c | 40 +++++++---------------------------------
 1 file changed, 7 insertions(+), 33 deletions(-)

diff --git a/src/guestfs.c b/src/guestfs.c
index 9060c11..15111db 100644
--- a/src/guestfs.c
+++ b/src/guestfs.c
@@ -650,7 +650,6 @@ guestfs_launch (guestfs_h *g)
   char *kernel = NULL, *initrd = NULL;
   char unixsock[256];
   struct sockaddr_un addr;
-  struct stat statbuf;
 
   /* Configured? */
   if (!g->cmdline) {
@@ -710,39 +709,14 @@ guestfs_launch (guestfs_h *g)
     goto cleanup0;
   }
 
-  /* Choose a suitable memory size (in MB).  This is more art
-   * than science, but you can help by doing
-   *   ./configure --enable-debug-command
-   * and then running:
-   *   debug sh free
-   *   debug mem ''
-   * and seeing how much free memory is left for particular
-   * configurations.
-   *
-   * It's also helpful to report both the compressed and uncompressed
-   * size of the initramfs (ls -lh initramfs*.img; du -sh initramfs).
-   *
-   * XXX KVM virtio balloon driver?
+  /* Choose a suitable memory size.  Previously we tried to choose
+   * a minimal memory size, but this isn't really necessary since
+   * recent QEMU and KVM don't do anything nasty like locking
+   * memory into core any more.  This we can safely choose a
+   * large, generous amount of memory, and it'll just get swapped
+   * on smaller systems.
    */
-  if (stat (initrd, &statbuf) != -1) {
-    /* Approximate size of the initramfs after it is decompressed
-     * in kernel memory.  The compression factor is ~2.5-3.
-     */
-    memsize = 3 * statbuf.st_size / 1024 / 1024;
-
-    /* Approximate size used by the kernel. */
-    memsize += 10;
-
-    /* Want to give userspace some room, so: */
-    memsize += 128;
-
-#if SIZEOF_LONG == 8
-    /* On 64 bit, assume some overhead. */
-    memsize += 64;
-#endif
-  } else
-    memsize = 512;
-  
+  memsize = 384;
 
   /* Make the temporary directory containing the socket. */
   if (!g->tmpdir) {
-- 
1.8.3.1