[Xen-changelog] [xen master] xen: arm: reduce the size of the xen heap to max 1/8 RAM size

[patchbot@xxxxxxx]

commit 08693f5948d88f70075a5c351f748f7668833efd
Author:     Ian Campbell <ian.campbell@xxxxxxxxxx>
AuthorDate: Tue Jul 23 18:12:26 2013 +0100
Commit:     Ian Campbell <ian.campbell@xxxxxxxxxx>
CommitDate: Tue Aug 20 15:42:30 2013 +0100

    xen: arm: reduce the size of the xen heap to max 1/8 RAM size
    
    When building a 1GB dom0 on a system with 2GB RAM we are running out of 
domheap
    pages, while there are still plenty of xenheap pages spare.
    
    I would have sworn that when the domheap was exhausted we would fall back to
    allocating xenheap pages but this doesn't appear to be the case. It's 
possible
    that we have setup something incorrectly on ARM but alloc_domheap_pages 
pretty
    clearly tries to allocate memory from MEMZONE_XEN+1..zone_hi.
    
    Without the fallback from domheap to xenheap taking 1GB of any system with 
>1GB
    of RAM for xenheap is excessive so instead set a limit of 1/8 of the total
    amount of RAM. By way of comparison x86_32 used to have a static 12MB 
xenheap
    (which also included .text etc) and in theory supported up to 16GB RAM, by 
that
    measure 1/8 is plenty.
    
    Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
    Acked-by: Tim Deegan <tim@xxxxxxx>
---
 xen/arch/arm/setup.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 1ec5e38..b184721 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -316,14 +316,14 @@ static void __init setup_mm(unsigned long dtb_paddr, 
size_t dtb_size)
      *
      *  - must be 32 MiB aligned
      *  - must not include Xen itself or the boot modules
-     *  - must be at most 1 GiB
+     *  - must be at most 1/8 the total RAM in the system
      *  - must be at least 128M
      *
      * We try to allocate the largest xenheap possible within these
      * constraints.
      */
     heap_pages = (ram_size >> PAGE_SHIFT);
-    xenheap_pages = min(1ul << (30 - PAGE_SHIFT), heap_pages);
+    xenheap_pages = max(heap_pages/8, 128UL<<(20-PAGE_SHIFT));
 
     do
     {
--
generated by git-patchbot for /home/xen/git/xen.git#master

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