Re: [Xen-devel] [PATCH] xen: centralize accounting for domain tot_pages

[Keir Fraser <keir@xxxxxxx>]

On 28/11/2012 21:50, "Dan Magenheimer" <dan.magenheimer@xxxxxxxxxx> wrote:

> xen: centralize accounting for domain tot_pages
> 
> Provide and use a common function for all adjustments to a
> domain's tot_pages counter in anticipation of future and/or
> out-of-tree patches that must adjust related counters
> atomically.
> 
> Signed-off-by: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>

Applied.

 -- Keir

>  arch/x86/mm.c             |    4 ++--
>  arch/x86/mm/mem_sharing.c |    4 ++--
>  common/grant_table.c      |    2 +-
>  common/memory.c           |    2 +-
>  common/page_alloc.c       |   10 ++++++++--
>  include/xen/mm.h          |    2 ++
>  6 files changed, 16 insertions(+), 8 deletions(-)
> 
> diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
> index ab94b02..3887ca6 100644
> --- a/xen/arch/x86/mm.c
> +++ b/xen/arch/x86/mm.c
> @@ -3842,7 +3842,7 @@ int donate_page(
>      {
>          if ( d->tot_pages >= d->max_pages )
>              goto fail;
> -        d->tot_pages++;
> +        domain_adjust_tot_pages(d, 1);
>      }
>  
>      page->count_info = PGC_allocated | 1;
> @@ -3892,7 +3892,7 @@ int steal_page(
>      } while ( (y = cmpxchg(&page->count_info, x, x | 1)) != x );
>  
>      /* Unlink from original owner. */
> -    if ( !(memflags & MEMF_no_refcount) && !--d->tot_pages )
> +    if ( !(memflags & MEMF_no_refcount) && !domain_adjust_tot_pages(d, -1) )
>          drop_dom_ref = 1;
>      page_list_del(page, &d->page_list);
>  
> diff --git a/xen/arch/x86/mm/mem_sharing.c b/xen/arch/x86/mm/mem_sharing.c
> index 5103285..e91aac5 100644
> --- a/xen/arch/x86/mm/mem_sharing.c
> +++ b/xen/arch/x86/mm/mem_sharing.c
> @@ -639,7 +639,7 @@ static int page_make_sharable(struct domain *d,
>      }
>  
>      page_set_owner(page, dom_cow);
> -    d->tot_pages--;
> +    domain_adjust_tot_pages(d, -1);
>      drop_dom_ref = (d->tot_pages == 0);
>      page_list_del(page, &d->page_list);
>      spin_unlock(&d->page_alloc_lock);
> @@ -680,7 +680,7 @@ static int page_make_private(struct domain *d, struct
> page_info *page)
>      ASSERT(page_get_owner(page) == dom_cow);
>      page_set_owner(page, d);
>  
> -    if ( d->tot_pages++ == 0 )
> +    if ( domain_adjust_tot_pages(d, 1) == 1 )
>          get_domain(d);
>      page_list_add_tail(page, &d->page_list);
>      spin_unlock(&d->page_alloc_lock);
> diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c
> index 7912769..ca8d861 100644
> --- a/xen/common/grant_table.c
> +++ b/xen/common/grant_table.c
> @@ -1656,7 +1656,7 @@ gnttab_transfer(
>          }
>  
>          /* Okay, add the page to 'e'. */
> -        if ( unlikely(e->tot_pages++ == 0) )
> +        if ( unlikely(domain_adjust_tot_pages(e, 1) == 1) )
>              get_knownalive_domain(e);
>          page_list_add_tail(page, &e->page_list);
>          page_set_owner(page, e);
> diff --git a/xen/common/memory.c b/xen/common/memory.c
> index 83e2666..9842ea9 100644
> --- a/xen/common/memory.c
> +++ b/xen/common/memory.c
> @@ -454,7 +454,7 @@ static long
> memory_exchange(XEN_GUEST_HANDLE_PARAM(xen_memory_exchange_t) arg)
>                               (j * (1UL << exch.out.extent_order)));
>  
>                  spin_lock(&d->page_alloc_lock);
> -                d->tot_pages -= dec_count;
> +                domain_adjust_tot_pages(d, -dec_count);
>                  drop_dom_ref = (dec_count && !d->tot_pages);
>                  spin_unlock(&d->page_alloc_lock);
>  
> diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
> index 15ebc66..e273bb7 100644
> --- a/xen/common/page_alloc.c
> +++ b/xen/common/page_alloc.c
> @@ -239,6 +239,12 @@ static long midsize_alloc_zone_pages;
>  
>  static DEFINE_SPINLOCK(heap_lock);
>  
> +unsigned long domain_adjust_tot_pages(struct domain *d, long pages)
> +{
> +    ASSERT(spin_is_locked(&d->page_alloc_lock));
> +    return d->tot_pages += pages;
> +}
> +
>  static unsigned long init_node_heap(int node, unsigned long mfn,
>                                      unsigned long nr, bool_t *use_tail)
>  {
> @@ -1291,7 +1297,7 @@ int assign_pages(
>          if ( unlikely(d->tot_pages == 0) )
>              get_knownalive_domain(d);
>  
> -        d->tot_pages += 1 << order;
> +        domain_adjust_tot_pages(d, 1 << order);
>      }
>  
>      for ( i = 0; i < (1 << order); i++ )
> @@ -1375,7 +1381,7 @@ void free_domheap_pages(struct page_info *pg, unsigned
> int order)
>              page_list_del2(&pg[i], &d->page_list, &d->arch.relmem_list);
>          }
>  
> -        d->tot_pages -= 1 << order;
> +        domain_adjust_tot_pages(d, -(1 << order));
>          drop_dom_ref = (d->tot_pages == 0);
>  
>          spin_unlock_recursive(&d->page_alloc_lock);
> diff --git a/xen/include/xen/mm.h b/xen/include/xen/mm.h
> index 64a0cc1..00b1915 100644
> --- a/xen/include/xen/mm.h
> +++ b/xen/include/xen/mm.h
> @@ -48,6 +48,8 @@ void free_xenheap_pages(void *v, unsigned int order);
>  #define alloc_xenheap_page() (alloc_xenheap_pages(0,0))
>  #define free_xenheap_page(v) (free_xenheap_pages(v,0))
>  
> +unsigned long domain_adjust_tot_pages(struct domain *d, long pages);
> +
>  /* Domain suballocator. These functions are *not* interrupt-safe.*/
>  void init_domheap_pages(paddr_t ps, paddr_t pe);
>  struct page_info *alloc_domheap_pages(



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