[Xen-devel] balloon patch

[David Becker <becker@xxxxxxxxxxx>]

Finally had time this week to look at memory sharing between domains.
Here is a balloon driver patch for xenolinux.   Inflation and deflation
no longer crash the guest os.   I'm not a Linux vm system expert so some
of this is guesswork.

David


*** 
../../xeno-unstable.bk/linux-2.4.26-xen-sparse//arch/xen/drivers/balloon/balloon.c
  Tue Jun 22 09:58:19 2004
--- linux-xen-sparse/arch/xen/drivers/balloon/balloon.c Wed Jun 30 09:32:40 2004
***************
*** 17,22 ****
--- 17,23 ----
  #include <linux/mman.h>
  #include <linux/smp_lock.h>
  #include <linux/pagemap.h>
+ #include <linux/vmalloc.h>
  
  #include <asm/hypervisor.h>
  #include <asm/pgalloc.h>
***************
*** 64,77 ****
      unsigned long vaddr;
      unsigned long i, j;
  
!     parray = (unsigned long *)kmalloc(num_pages * sizeof(unsigned long),
!                                       GFP_KERNEL);
      currp = parray;
  
      for ( i = 0; i < num_pages; i++ )
      {
          /* Try to obtain a free page (has to be done with GFP_ATOMIC). */
!         vaddr = __get_free_page(GFP_ATOMIC);
  
          /* If allocation fails then free all reserved pages. */
          if ( vaddr == 0 )
--- 65,82 ----
      unsigned long vaddr;
      unsigned long i, j;
  
!     parray = (unsigned long *)vmalloc(num_pages * sizeof(unsigned long));
!     if (!parray)
!     {
!         printk("inflate_balloon: Unable to vmalloc parray\n");
!         return 0;
!     }
      currp = parray;
  
      for ( i = 0; i < num_pages; i++ )
      {
          /* Try to obtain a free page (has to be done with GFP_ATOMIC). */
!         vaddr = __get_free_page(GFP_KERNEL);
  
          /* If allocation fails then free all reserved pages. */
          if ( vaddr == 0 )
***************
*** 113,119 ****
      ret = num_pages;
  
   cleanup:
!     kfree(parray);
  
      return ret;
  }
--- 119,125 ----
      ret = num_pages;
  
   cleanup:
!     vfree(parray);
  
      return ret;
  }
***************
*** 143,150 ****
          if ( phys_to_machine_mapping[i] == DEAD )
          {
              phys_to_machine_mapping[i] = *curr;
!             queue_l1_entry_update(
!                 (pte_t *)((i << PAGE_SHIFT) | MMU_MACHPHYS_UPDATE), i);
              queue_l1_entry_update(
                  get_ptep((unsigned long)__va(i << PAGE_SHIFT)),
                  ((*curr) << PAGE_SHIFT) | pgprot_val(PAGE_KERNEL));
--- 149,155 ----
          if ( phys_to_machine_mapping[i] == DEAD )
          {
              phys_to_machine_mapping[i] = *curr;
!             queue_machphys_update(*curr, i);
              queue_l1_entry_update(
                  get_ptep((unsigned long)__va(i << PAGE_SHIFT)),
                  ((*curr) << PAGE_SHIFT) | pgprot_val(PAGE_KERNEL));
***************
*** 181,188 ****
          return -EAGAIN;
      }
  
!     parray = (unsigned long *)kmalloc(num_pages * sizeof(unsigned long), 
!                                       GFP_KERNEL);
  
      ret = HYPERVISOR_dom_mem_op(MEMOP_increase_reservation, 
                                  parray, num_pages);
--- 186,198 ----
          return -EAGAIN;
      }
  
!     parray = (unsigned long *)vmalloc(num_pages * sizeof(unsigned long));
!     if (!parray)
!     {
!         printk("deflate_balloon: Unable to vmalloc parray\n");
!         return 0;
!     }
!     XEN_flush_page_update_queue();
  
      ret = HYPERVISOR_dom_mem_op(MEMOP_increase_reservation, 
                                  parray, num_pages);
***************
*** 203,209 ****
      credit -= num_pages;
  
   cleanup:
!     kfree(parray);
  
      return ret;
  }
--- 213,219 ----
      credit -= num_pages;
  
   cleanup:
!     vfree(parray);
  
      return ret;
  }


-------------------------------------------------------
This SF.Net email sponsored by Black Hat Briefings & Training.
Attend Black Hat Briefings & Training, Las Vegas July 24-29 - 
digital self defense, top technical experts, no vendor pitches, 
unmatched networking opportunities. Visit www.blackhat.com
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/xen-devel