[PATCH][2/4] Enable 1GB for Xen HVM host page

[PATCH][2/4] Enable 1GB for Xen HVM host page

[Wei Huang]

[-- Attachment #1: Type: text/plain, Size: 233 bytes --]

Change page allocation code in Xen tools. The allocation request now 
starts with 1GB; if that fails, then falls back to 2MB and then 4KB.

Signed-off-by: Wei Huang <wei.huang2@amd.com>
Acked-by: Dongxiao Xu <dongxiao.xu@intel.com>


[-- Attachment #2: 2-xen-hap-fix-tools.patch --]
[-- Type: text/x-patch, Size: 7344 bytes --]

# HG changeset patch
# User huangwei@huangwei.amd.com
# Date 1266853449 21600
# Node ID c9b45664b423e11003358944bb8e6e976e735301
# Parent  1d166c5703256ab97225c6ae46ac87dd5bd07e89
fix the tools to support 1GB. Create 1GB pages if possible; otherwise falls back to 2MB then 4KB.

diff -r 1d166c570325 -r c9b45664b423 tools/libxc/xc_hvm_build.c
--- a/tools/libxc/xc_hvm_build.c	Mon Feb 22 09:44:04 2010 -0600
+++ b/tools/libxc/xc_hvm_build.c	Mon Feb 22 09:44:09 2010 -0600
@@ -19,8 +19,10 @@
 
 #include <xen/libelf/libelf.h>
 
-#define SUPERPAGE_PFN_SHIFT  9
-#define SUPERPAGE_NR_PFNS    (1UL << SUPERPAGE_PFN_SHIFT)
+#define SUPERPAGE_2MB_SHIFT   9
+#define SUPERPAGE_2MB_NR_PFNS (1UL << SUPERPAGE_2MB_SHIFT)
+#define SUPERPAGE_1GB_SHIFT   18
+#define SUPERPAGE_1GB_NR_PFNS (1UL << SUPERPAGE_1GB_SHIFT)
 
 #define SPECIALPAGE_BUFIOREQ 0
 #define SPECIALPAGE_XENSTORE 1
@@ -117,6 +119,8 @@
     uint64_t v_start, v_end;
     int rc;
     xen_capabilities_info_t caps;
+    unsigned long stat_normal_pages = 0, stat_2mb_pages = 0, 
+        stat_1gb_pages = 0;
     int pod_mode = 0;
     
 
@@ -166,35 +170,43 @@
 
     /*
      * Allocate memory for HVM guest, skipping VGA hole 0xA0000-0xC0000.
-     * We allocate pages in batches of no more than 8MB to ensure that
-     * we can be preempted and hence dom0 remains responsive.
+     *
+     * We attempt to allocate 1GB pages if possible. It falls back on 2MB
+     * pages if 1GB allocation fails. 4KB pages will be used eventually if
+     * both fail.
+     * 
+     * Under 2MB mode, we allocate pages in batches of no more than 8MB to 
+     * ensure that we can be preempted and hence dom0 remains responsive.
      */
     rc = xc_domain_memory_populate_physmap(
         xc_handle, dom, 0xa0, 0, 0, &page_array[0x00]);
     cur_pages = 0xc0;
+    stat_normal_pages = 0xc0;
     while ( (rc == 0) && (nr_pages > cur_pages) )
     {
         /* Clip count to maximum 8MB extent. */
         unsigned long count = nr_pages - cur_pages;
-        if ( count > 2048 )
-            count = 2048;
+        unsigned long max_pages = SUPERPAGE_1GB_NR_PFNS;
 
-        /* Clip partial superpage extents to superpage boundaries. */
-        if ( ((cur_pages & (SUPERPAGE_NR_PFNS-1)) != 0) &&
-             (count > (-cur_pages & (SUPERPAGE_NR_PFNS-1))) )
-            count = -cur_pages & (SUPERPAGE_NR_PFNS-1); /* clip s.p. tail */
-        else if ( ((count & (SUPERPAGE_NR_PFNS-1)) != 0) &&
-                  (count > SUPERPAGE_NR_PFNS) )
-            count &= ~(SUPERPAGE_NR_PFNS - 1); /* clip non-s.p. tail */
+        if ( count > max_pages )
+            count = max_pages;
+        
+        /* Take care the corner cases of super page tails */
+        if ( ((cur_pages & (SUPERPAGE_1GB_NR_PFNS-1)) != 0) &&
+             (count > (-cur_pages & (SUPERPAGE_1GB_NR_PFNS-1))) )
+            count = -cur_pages & (SUPERPAGE_1GB_NR_PFNS-1);
+        else if ( ((count & (SUPERPAGE_1GB_NR_PFNS-1)) != 0) &&
+                  (count > SUPERPAGE_1GB_NR_PFNS) )
+            count &= ~(SUPERPAGE_1GB_NR_PFNS - 1);
 
-        /* Attempt to allocate superpage extents. */
-        if ( ((count | cur_pages) & (SUPERPAGE_NR_PFNS - 1)) == 0 )
+        /* Attemp to allocate 1GB super page */
+        if ( ((count | cur_pages) & (SUPERPAGE_1GB_NR_PFNS - 1)) == 0 )
         {
             long done;
-            xen_pfn_t sp_extents[count >> SUPERPAGE_PFN_SHIFT];
+            xen_pfn_t sp_extents[count >> SUPERPAGE_1GB_SHIFT];
             struct xen_memory_reservation sp_req = {
-                .nr_extents   = count >> SUPERPAGE_PFN_SHIFT,
-                .extent_order = SUPERPAGE_PFN_SHIFT,
+                .nr_extents   = count >> SUPERPAGE_1GB_SHIFT,
+                .extent_order = SUPERPAGE_1GB_SHIFT,
                 .domid        = dom
             };
 
@@ -203,11 +215,12 @@
 
             set_xen_guest_handle(sp_req.extent_start, sp_extents);
             for ( i = 0; i < sp_req.nr_extents; i++ )
-                sp_extents[i] = page_array[cur_pages+(i<<SUPERPAGE_PFN_SHIFT)];
+                sp_extents[i] = page_array[cur_pages+(i<<SUPERPAGE_1GB_SHIFT)];
             done = xc_memory_op(xc_handle, XENMEM_populate_physmap, &sp_req);
             if ( done > 0 )
             {
-                done <<= SUPERPAGE_PFN_SHIFT;
+                stat_1gb_pages += done;
+                done <<= SUPERPAGE_1GB_SHIFT;
                 if ( pod_mode && target_pages > cur_pages )
                 {
                     int d = target_pages - cur_pages;
@@ -218,12 +231,60 @@
             }
         }
 
+        if ( count != 0 )
+        {
+            max_pages = 2048;
+            if ( count > max_pages )
+                count = max_pages;
+            
+            /* Clip partial superpage extents to superpage boundaries. */
+            if ( ((cur_pages & (SUPERPAGE_2MB_NR_PFNS-1)) != 0) &&
+                 (count > (-cur_pages & (SUPERPAGE_2MB_NR_PFNS-1))) )
+                count = -cur_pages & (SUPERPAGE_2MB_NR_PFNS-1);
+            else if ( ((count & (SUPERPAGE_2MB_NR_PFNS-1)) != 0) &&
+                  (count > SUPERPAGE_2MB_NR_PFNS) )
+            count &= ~(SUPERPAGE_2MB_NR_PFNS - 1); /* clip non-s.p. tail */
+
+            /* Attempt to allocate superpage extents. */
+            if ( ((count | cur_pages) & (SUPERPAGE_2MB_NR_PFNS - 1)) == 0 )
+            {
+                long done;
+                xen_pfn_t sp_extents[count >> SUPERPAGE_2MB_SHIFT];
+                struct xen_memory_reservation sp_req = {
+                    .nr_extents   = count >> SUPERPAGE_2MB_SHIFT,
+                    .extent_order = SUPERPAGE_2MB_SHIFT,
+                    .domid        = dom
+                };
+
+                if ( pod_mode )
+                    sp_req.mem_flags = XENMEMF_populate_on_demand;
+
+                set_xen_guest_handle(sp_req.extent_start, sp_extents);
+                for ( i = 0; i < sp_req.nr_extents; i++ )
+                    sp_extents[i] = page_array[cur_pages+(i<<SUPERPAGE_2MB_SHIFT)];
+                done = xc_memory_op(xc_handle, XENMEM_populate_physmap, &sp_req);
+                if ( done > 0 )
+                {
+                    stat_2mb_pages += done;
+                    done <<= SUPERPAGE_2MB_SHIFT;
+                    if ( pod_mode && target_pages > cur_pages )
+                    {
+                        int d = target_pages - cur_pages;
+                        pod_pages += ( done < d ) ? done : d;
+                    }
+                    cur_pages += done;
+                    count -= done;
+                }
+            }
+        }
+
         /* Fall back to 4kB extents. */
         if ( count != 0 )
         {
             rc = xc_domain_memory_populate_physmap(
                 xc_handle, dom, count, 0, 0, &page_array[cur_pages]);
             cur_pages += count;
+            stat_normal_pages += count;
             if ( pod_mode )
                 pod_pages -= count;
         }
@@ -241,6 +302,12 @@
         goto error_out;
     }
 
+    IPRINTF("PHYSICAL MEMORY ALLOCATION:\n"
+            "  4KB PAGES: 0x%016lx\n"
+            "  2MB PAGES: 0x%016lx\n"
+            "  1GB PAGES: 0x%016lx\n",
+            stat_normal_pages, stat_2mb_pages, stat_1gb_pages);
+    
     if ( loadelfimage(&elf, xc_handle, dom, page_array) != 0 )
         goto error_out;
 

[-- Attachment #3: Type: text/plain, Size: 138 bytes --]

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Re: [PATCH][2/4] Enable 1GB for Xen HVM host page

[Tim Deegan]

At 17:18 +0000 on 22 Feb (1266859100), Wei Huang wrote:
> Change page allocation code in Xen tools. The allocation request now 
> starts with 1GB; if that fails, then falls back to 2MB and then 4KB.
> 
> Signed-off-by: Wei Huang <wei.huang2@amd.com>
> Acked-by: Dongxiao Xu <dongxiao.xu@intel.com>
> 

Content-Description: 2-xen-hap-fix-tools.patch
> # HG changeset patch
> # User huangwei@huangwei.amd.com
> # Date 1266853449 21600
> # Node ID c9b45664b423e11003358944bb8e6e976e735301
> # Parent  1d166c5703256ab97225c6ae46ac87dd5bd07e89
> fix the tools to support 1GB. Create 1GB pages if possible; otherwise falls back to 2MB then 4KB.
> 
> diff -r 1d166c570325 -r c9b45664b423 tools/libxc/xc_hvm_build.c
> --- a/tools/libxc/xc_hvm_build.c	Mon Feb 22 09:44:04 2010 -0600
> +++ b/tools/libxc/xc_hvm_build.c	Mon Feb 22 09:44:09 2010 -0600
> @@ -19,8 +19,10 @@
>  
>  #include <xen/libelf/libelf.h>
>  
> -#define SUPERPAGE_PFN_SHIFT  9
> -#define SUPERPAGE_NR_PFNS    (1UL << SUPERPAGE_PFN_SHIFT)
> +#define SUPERPAGE_2MB_SHIFT   9
> +#define SUPERPAGE_2MB_NR_PFNS (1UL << SUPERPAGE_2MB_SHIFT)
> +#define SUPERPAGE_1GB_SHIFT   18
> +#define SUPERPAGE_1GB_NR_PFNS (1UL << SUPERPAGE_1GB_SHIFT)
>  
>  #define SPECIALPAGE_BUFIOREQ 0
>  #define SPECIALPAGE_XENSTORE 1
> @@ -117,6 +119,8 @@
>      uint64_t v_start, v_end;
>      int rc;
>      xen_capabilities_info_t caps;
> +    unsigned long stat_normal_pages = 0, stat_2mb_pages = 0, 
> +        stat_1gb_pages = 0;
>      int pod_mode = 0;
>      
>  
> @@ -166,35 +170,43 @@
>  
>      /*
>       * Allocate memory for HVM guest, skipping VGA hole 0xA0000-0xC0000.
> -     * We allocate pages in batches of no more than 8MB to ensure that
> -     * we can be preempted and hence dom0 remains responsive.
> +     *
> +     * We attempt to allocate 1GB pages if possible. It falls back on 2MB
> +     * pages if 1GB allocation fails. 4KB pages will be used eventually if
> +     * both fail.
> +     * 
> +     * Under 2MB mode, we allocate pages in batches of no more than 8MB to 
> +     * ensure that we can be preempted and hence dom0 remains responsive.
>       */
>      rc = xc_domain_memory_populate_physmap(
>          xc_handle, dom, 0xa0, 0, 0, &page_array[0x00]);
>      cur_pages = 0xc0;
> +    stat_normal_pages = 0xc0;
>      while ( (rc == 0) && (nr_pages > cur_pages) )
>      {
>          /* Clip count to maximum 8MB extent. */

ITYM 1GB here. 

>          unsigned long count = nr_pages - cur_pages;
> -        if ( count > 2048 )
> -            count = 2048;
> +        unsigned long max_pages = SUPERPAGE_1GB_NR_PFNS;
>  
> -        /* Clip partial superpage extents to superpage boundaries. */
> -        if ( ((cur_pages & (SUPERPAGE_NR_PFNS-1)) != 0) &&
> -             (count > (-cur_pages & (SUPERPAGE_NR_PFNS-1))) )
> -            count = -cur_pages & (SUPERPAGE_NR_PFNS-1); /* clip s.p. tail */
> -        else if ( ((count & (SUPERPAGE_NR_PFNS-1)) != 0) &&
> -                  (count > SUPERPAGE_NR_PFNS) )
> -            count &= ~(SUPERPAGE_NR_PFNS - 1); /* clip non-s.p. tail */
> +        if ( count > max_pages )
> +            count = max_pages;
> +        
> +        /* Take care the corner cases of super page tails */
> +        if ( ((cur_pages & (SUPERPAGE_1GB_NR_PFNS-1)) != 0) &&
> +             (count > (-cur_pages & (SUPERPAGE_1GB_NR_PFNS-1))) )
> +            count = -cur_pages & (SUPERPAGE_1GB_NR_PFNS-1);
> +        else if ( ((count & (SUPERPAGE_1GB_NR_PFNS-1)) != 0) &&
> +                  (count > SUPERPAGE_1GB_NR_PFNS) )
> +            count &= ~(SUPERPAGE_1GB_NR_PFNS - 1);

This logic is overkill since you allocate at most one 1GB page in each
pass.  In fact, given that you test for <1GB immediately below, I think
you can just drop this 'tails' chunk entirely.

>  
> -        /* Attempt to allocate superpage extents. */
> -        if ( ((count | cur_pages) & (SUPERPAGE_NR_PFNS - 1)) == 0 )
> +        /* Attemp to allocate 1GB super page */
> +        if ( ((count | cur_pages) & (SUPERPAGE_1GB_NR_PFNS - 1)) == 0 )
>          {
>              long done;
> -            xen_pfn_t sp_extents[count >> SUPERPAGE_PFN_SHIFT];
> +            xen_pfn_t sp_extents[count >> SUPERPAGE_1GB_SHIFT];
>              struct xen_memory_reservation sp_req = {
> -                .nr_extents   = count >> SUPERPAGE_PFN_SHIFT,
> -                .extent_order = SUPERPAGE_PFN_SHIFT,
> +                .nr_extents   = count >> SUPERPAGE_1GB_SHIFT,
> +                .extent_order = SUPERPAGE_1GB_SHIFT,
>                  .domid        = dom
>              };
>  
> @@ -203,11 +215,12 @@
>  
>              set_xen_guest_handle(sp_req.extent_start, sp_extents);
>              for ( i = 0; i < sp_req.nr_extents; i++ )
> -                sp_extents[i] = page_array[cur_pages+(i<<SUPERPAGE_PFN_SHIFT)];
> +                sp_extents[i] = page_array[cur_pages+(i<<SUPERPAGE_1GB_SHIFT)];
>              done = xc_memory_op(xc_handle, XENMEM_populate_physmap, &sp_req);
>              if ( done > 0 )
>              {
> -                done <<= SUPERPAGE_PFN_SHIFT;
> +                stat_1gb_pages += done;
> +                done <<= SUPERPAGE_1GB_SHIFT;
>                  if ( pod_mode && target_pages > cur_pages )
>                  {
>                      int d = target_pages - cur_pages;
> @@ -218,12 +231,60 @@
>              }
>          }
>  
> +        if ( count != 0 )
> +        {
> +            max_pages = 2048;

Call this (SUPERPAGE_2MB_NR_PFNS * 4)?


Cheers,

Tim.

-- 
Tim Deegan <Tim.Deegan@citrix.com>
Principal Software Engineer, XenServer Engineering
Citrix Systems UK Ltd.  (Company #02937203, SL9 0BG)

Re: [PATCH][2/4] Enable 1GB for Xen HVM host page

[Tim Deegan]

At 17:18 +0000 on 22 Feb (1266859100), Wei Huang wrote:
> Change page allocation code in Xen tools. The allocation request now 
> starts with 1GB; if that fails, then falls back to 2MB and then 4KB.

Can we have an equivalent patch for the save/restore path please?  That
took a while to catch up when 2MB superpages were introduced.

Tim.

-- 
Tim Deegan <Tim.Deegan@citrix.com>
Principal Software Engineer, XenServer Engineering
Citrix Systems UK Ltd.  (Company #02937203, SL9 0BG)

RE: [PATCH][2/4] Enable 1GB for Xen HVM host page

[Huang2, Wei]

Tim,

Thanks for the comments. I will fix them according to your comments, along with making save/restore work.

Best,
-Wei

-----Original Message-----
From: Tim Deegan [mailto:Tim.Deegan@citrix.com] 
Sent: Tuesday, February 23, 2010 3:39 AM
To: Huang2, Wei
Cc: 'xen-devel@lists.xensource.com'; Keir Fraser; Xu, Dongxiao
Subject: Re: [Xen-devel] [PATCH][2/4] Enable 1GB for Xen HVM host page

At 17:18 +0000 on 22 Feb (1266859100), Wei Huang wrote:
> Change page allocation code in Xen tools. The allocation request now 
> starts with 1GB; if that fails, then falls back to 2MB and then 4KB.
> 
> Signed-off-by: Wei Huang <wei.huang2@amd.com>
> Acked-by: Dongxiao Xu <dongxiao.xu@intel.com>
> 

Content-Description: 2-xen-hap-fix-tools.patch
> # HG changeset patch
> # User huangwei@huangwei.amd.com
> # Date 1266853449 21600
> # Node ID c9b45664b423e11003358944bb8e6e976e735301
> # Parent  1d166c5703256ab97225c6ae46ac87dd5bd07e89
> fix the tools to support 1GB. Create 1GB pages if possible; otherwise falls back to 2MB then 4KB.
> 
> diff -r 1d166c570325 -r c9b45664b423 tools/libxc/xc_hvm_build.c
> --- a/tools/libxc/xc_hvm_build.c	Mon Feb 22 09:44:04 2010 -0600
> +++ b/tools/libxc/xc_hvm_build.c	Mon Feb 22 09:44:09 2010 -0600
> @@ -19,8 +19,10 @@
>  
>  #include <xen/libelf/libelf.h>
>  
> -#define SUPERPAGE_PFN_SHIFT  9
> -#define SUPERPAGE_NR_PFNS    (1UL << SUPERPAGE_PFN_SHIFT)
> +#define SUPERPAGE_2MB_SHIFT   9
> +#define SUPERPAGE_2MB_NR_PFNS (1UL << SUPERPAGE_2MB_SHIFT)
> +#define SUPERPAGE_1GB_SHIFT   18
> +#define SUPERPAGE_1GB_NR_PFNS (1UL << SUPERPAGE_1GB_SHIFT)
>  
>  #define SPECIALPAGE_BUFIOREQ 0
>  #define SPECIALPAGE_XENSTORE 1
> @@ -117,6 +119,8 @@
>      uint64_t v_start, v_end;
>      int rc;
>      xen_capabilities_info_t caps;
> +    unsigned long stat_normal_pages = 0, stat_2mb_pages = 0, 
> +        stat_1gb_pages = 0;
>      int pod_mode = 0;
>      
>  
> @@ -166,35 +170,43 @@
>  
>      /*
>       * Allocate memory for HVM guest, skipping VGA hole 0xA0000-0xC0000.
> -     * We allocate pages in batches of no more than 8MB to ensure that
> -     * we can be preempted and hence dom0 remains responsive.
> +     *
> +     * We attempt to allocate 1GB pages if possible. It falls back on 2MB
> +     * pages if 1GB allocation fails. 4KB pages will be used eventually if
> +     * both fail.
> +     * 
> +     * Under 2MB mode, we allocate pages in batches of no more than 8MB to 
> +     * ensure that we can be preempted and hence dom0 remains responsive.
>       */
>      rc = xc_domain_memory_populate_physmap(
>          xc_handle, dom, 0xa0, 0, 0, &page_array[0x00]);
>      cur_pages = 0xc0;
> +    stat_normal_pages = 0xc0;
>      while ( (rc == 0) && (nr_pages > cur_pages) )
>      {
>          /* Clip count to maximum 8MB extent. */

ITYM 1GB here. 

>          unsigned long count = nr_pages - cur_pages;
> -        if ( count > 2048 )
> -            count = 2048;
> +        unsigned long max_pages = SUPERPAGE_1GB_NR_PFNS;
>  
> -        /* Clip partial superpage extents to superpage boundaries. */
> -        if ( ((cur_pages & (SUPERPAGE_NR_PFNS-1)) != 0) &&
> -             (count > (-cur_pages & (SUPERPAGE_NR_PFNS-1))) )
> -            count = -cur_pages & (SUPERPAGE_NR_PFNS-1); /* clip s.p. tail */
> -        else if ( ((count & (SUPERPAGE_NR_PFNS-1)) != 0) &&
> -                  (count > SUPERPAGE_NR_PFNS) )
> -            count &= ~(SUPERPAGE_NR_PFNS - 1); /* clip non-s.p. tail */
> +        if ( count > max_pages )
> +            count = max_pages;
> +        
> +        /* Take care the corner cases of super page tails */
> +        if ( ((cur_pages & (SUPERPAGE_1GB_NR_PFNS-1)) != 0) &&
> +             (count > (-cur_pages & (SUPERPAGE_1GB_NR_PFNS-1))) )
> +            count = -cur_pages & (SUPERPAGE_1GB_NR_PFNS-1);
> +        else if ( ((count & (SUPERPAGE_1GB_NR_PFNS-1)) != 0) &&
> +                  (count > SUPERPAGE_1GB_NR_PFNS) )
> +            count &= ~(SUPERPAGE_1GB_NR_PFNS - 1);

This logic is overkill since you allocate at most one 1GB page in each
pass.  In fact, given that you test for <1GB immediately below, I think
you can just drop this 'tails' chunk entirely.

>  
> -        /* Attempt to allocate superpage extents. */
> -        if ( ((count | cur_pages) & (SUPERPAGE_NR_PFNS - 1)) == 0 )
> +        /* Attemp to allocate 1GB super page */
> +        if ( ((count | cur_pages) & (SUPERPAGE_1GB_NR_PFNS - 1)) == 0 )
>          {
>              long done;
> -            xen_pfn_t sp_extents[count >> SUPERPAGE_PFN_SHIFT];
> +            xen_pfn_t sp_extents[count >> SUPERPAGE_1GB_SHIFT];
>              struct xen_memory_reservation sp_req = {
> -                .nr_extents   = count >> SUPERPAGE_PFN_SHIFT,
> -                .extent_order = SUPERPAGE_PFN_SHIFT,
> +                .nr_extents   = count >> SUPERPAGE_1GB_SHIFT,
> +                .extent_order = SUPERPAGE_1GB_SHIFT,
>                  .domid        = dom
>              };
>  
> @@ -203,11 +215,12 @@
>  
>              set_xen_guest_handle(sp_req.extent_start, sp_extents);
>              for ( i = 0; i < sp_req.nr_extents; i++ )
> -                sp_extents[i] = page_array[cur_pages+(i<<SUPERPAGE_PFN_SHIFT)];
> +                sp_extents[i] = page_array[cur_pages+(i<<SUPERPAGE_1GB_SHIFT)];
>              done = xc_memory_op(xc_handle, XENMEM_populate_physmap, &sp_req);
>              if ( done > 0 )
>              {
> -                done <<= SUPERPAGE_PFN_SHIFT;
> +                stat_1gb_pages += done;
> +                done <<= SUPERPAGE_1GB_SHIFT;
>                  if ( pod_mode && target_pages > cur_pages )
>                  {
>                      int d = target_pages - cur_pages;
> @@ -218,12 +231,60 @@
>              }
>          }
>  
> +        if ( count != 0 )
> +        {
> +            max_pages = 2048;

Call this (SUPERPAGE_2MB_NR_PFNS * 4)?


Cheers,

Tim.

-- 
Tim Deegan <Tim.Deegan@citrix.com>
Principal Software Engineer, XenServer Engineering
Citrix Systems UK Ltd.  (Company #02937203, SL9 0BG)

RE: [PATCH][2/4] Enable 1GB for Xen HVM host page

[Dan Magenheimer]

I'll bet save/restore/migration for 1GB pages will be a fun challenge.

At least please set the "no_migrate" flag automatically for
any domain that uses 1GB pages unless/until live migration
is supported.

> -----Original Message-----
> From: Tim Deegan [mailto:Tim.Deegan@citrix.com]
> Sent: Tuesday, February 23, 2010 6:01 AM
> To: Wei Huang
> Cc: Keir@acsinet12.oracle.com; Xu, Dongxiao; xen-
> devel@lists.xensource.com; Fraser
> Subject: Re: [Xen-devel] [PATCH][2/4] Enable 1GB for Xen HVM host page
> 
> At 17:18 +0000 on 22 Feb (1266859100), Wei Huang wrote:
> > Change page allocation code in Xen tools. The allocation request now
> > starts with 1GB; if that fails, then falls back to 2MB and then 4KB.
> 
> Can we have an equivalent patch for the save/restore path please?  That
> took a while to catch up when 2MB superpages were introduced.
> 
> Tim.
> 
> --
> Tim Deegan <Tim.Deegan@citrix.com>
> Principal Software Engineer, XenServer Engineering
> Citrix Systems UK Ltd.  (Company #02937203, SL9 0BG)
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel

Re: [PATCH][2/4] Enable 1GB for Xen HVM host page

[Keir Fraser]

The use of 1GB extents is just a (small-ish) performance win. If you can
only back with 4kB or 2MB extents on the target host it doesn't matter that
much.

 -- Keir

On 23/02/2010 17:19, "Dan Magenheimer" <dan.magenheimer@oracle.com> wrote:

> I'll bet save/restore/migration for 1GB pages will be a fun challenge.
> 
> At least please set the "no_migrate" flag automatically for
> any domain that uses 1GB pages unless/until live migration
> is supported.
> 
>> -----Original Message-----
>> From: Tim Deegan [mailto:Tim.Deegan@citrix.com]
>> Sent: Tuesday, February 23, 2010 6:01 AM
>> To: Wei Huang
>> Cc: Keir@acsinet12.oracle.com; Xu, Dongxiao; xen-
>> devel@lists.xensource.com; Fraser
>> Subject: Re: [Xen-devel] [PATCH][2/4] Enable 1GB for Xen HVM host page
>> 
>> At 17:18 +0000 on 22 Feb (1266859100), Wei Huang wrote:
>>> Change page allocation code in Xen tools. The allocation request now
>>> starts with 1GB; if that fails, then falls back to 2MB and then 4KB.
>> 
>> Can we have an equivalent patch for the save/restore path please?  That
>> took a while to catch up when 2MB superpages were introduced.
>> 
>> Tim.
>> 
>> --
>> Tim Deegan <Tim.Deegan@citrix.com>
>> Principal Software Engineer, XenServer Engineering
>> Citrix Systems UK Ltd.  (Company #02937203, SL9 0BG)
>> 
>> _______________________________________________
>> Xen-devel mailing list
>> Xen-devel@lists.xensource.com
>> http://lists.xensource.com/xen-devel

RE: [PATCH][2/4] Enable 1GB for Xen HVM host page

[Dan Magenheimer]

Not sure what your point is.  I was just suggesting that if
save/restore/migration doesn't work anyway, setting no_migrate
should result in a nicer error message than otherwise, and serves
as a clear "TO DO" marker for developers looking for a
"fun" project.

> -----Original Message-----
> From: Keir Fraser [mailto:keir.fraser@eu.citrix.com]
> Sent: Tuesday, February 23, 2010 11:10 AM
> To: Dan Magenheimer; Tim Deegan; Wei Huang
> Cc: Keir@acsinet12.oracle.com; Xu, Dongxiao; xen-
> devel@lists.xensource.com
> Subject: Re: [Xen-devel] [PATCH][2/4] Enable 1GB for Xen HVM host page
> 
> The use of 1GB extents is just a (small-ish) performance win. If you
> can
> only back with 4kB or 2MB extents on the target host it doesn't matter
> that
> much.
> 
>  -- Keir
> 
> On 23/02/2010 17:19, "Dan Magenheimer" <dan.magenheimer@oracle.com>
> wrote:
> 
> > I'll bet save/restore/migration for 1GB pages will be a fun
> challenge.
> >
> > At least please set the "no_migrate" flag automatically for
> > any domain that uses 1GB pages unless/until live migration
> > is supported.
> >
> >> -----Original Message-----
> >> From: Tim Deegan [mailto:Tim.Deegan@citrix.com]
> >> Sent: Tuesday, February 23, 2010 6:01 AM
> >> To: Wei Huang
> >> Cc: Keir@acsinet12.oracle.com; Xu, Dongxiao; xen-
> >> devel@lists.xensource.com; Fraser
> >> Subject: Re: [Xen-devel] [PATCH][2/4] Enable 1GB for Xen HVM host
> page
> >>
> >> At 17:18 +0000 on 22 Feb (1266859100), Wei Huang wrote:
> >>> Change page allocation code in Xen tools. The allocation request
> now
> >>> starts with 1GB; if that fails, then falls back to 2MB and then
> 4KB.
> >>
> >> Can we have an equivalent patch for the save/restore path please?
> That
> >> took a while to catch up when 2MB superpages were introduced.
> >>
> >> Tim.
> >>
> >> --
> >> Tim Deegan <Tim.Deegan@citrix.com>
> >> Principal Software Engineer, XenServer Engineering
> >> Citrix Systems UK Ltd.  (Company #02937203, SL9 0BG)
> >>
> >> _______________________________________________
> >> Xen-devel mailing list
> >> Xen-devel@lists.xensource.com
> >> http://lists.xensource.com/xen-devel
> 
> 

Re: [PATCH][2/4] Enable 1GB for Xen HVM host page

[Keir Fraser]

Save/restore/migrate will work just fine as is. You just won't get 1GB pages
at the receiving end.

 -- Keir

On 23/02/2010 20:09, "Dan Magenheimer" <dan.magenheimer@oracle.com> wrote:

> Not sure what your point is.  I was just suggesting that if
> save/restore/migration doesn't work anyway, setting no_migrate
> should result in a nicer error message than otherwise, and serves
> as a clear "TO DO" marker for developers looking for a
> "fun" project.
> 
>> -----Original Message-----
>> From: Keir Fraser [mailto:keir.fraser@eu.citrix.com]
>> Sent: Tuesday, February 23, 2010 11:10 AM
>> To: Dan Magenheimer; Tim Deegan; Wei Huang
>> Cc: Keir@acsinet12.oracle.com; Xu, Dongxiao; xen-
>> devel@lists.xensource.com
>> Subject: Re: [Xen-devel] [PATCH][2/4] Enable 1GB for Xen HVM host page
>> 
>> The use of 1GB extents is just a (small-ish) performance win. If you
>> can
>> only back with 4kB or 2MB extents on the target host it doesn't matter
>> that
>> much.
>> 
>>  -- Keir
>> 
>> On 23/02/2010 17:19, "Dan Magenheimer" <dan.magenheimer@oracle.com>
>> wrote:
>> 
>>> I'll bet save/restore/migration for 1GB pages will be a fun
>> challenge.
>>> 
>>> At least please set the "no_migrate" flag automatically for
>>> any domain that uses 1GB pages unless/until live migration
>>> is supported.
>>> 
>>>> -----Original Message-----
>>>> From: Tim Deegan [mailto:Tim.Deegan@citrix.com]
>>>> Sent: Tuesday, February 23, 2010 6:01 AM
>>>> To: Wei Huang
>>>> Cc: Keir@acsinet12.oracle.com; Xu, Dongxiao; xen-
>>>> devel@lists.xensource.com; Fraser
>>>> Subject: Re: [Xen-devel] [PATCH][2/4] Enable 1GB for Xen HVM host
>> page
>>>> 
>>>> At 17:18 +0000 on 22 Feb (1266859100), Wei Huang wrote:
>>>>> Change page allocation code in Xen tools. The allocation request
>> now
>>>>> starts with 1GB; if that fails, then falls back to 2MB and then
>> 4KB.
>>>> 
>>>> Can we have an equivalent patch for the save/restore path please?
>> That
>>>> took a while to catch up when 2MB superpages were introduced.
>>>> 
>>>> Tim.
>>>> 
>>>> --
>>>> Tim Deegan <Tim.Deegan@citrix.com>
>>>> Principal Software Engineer, XenServer Engineering
>>>> Citrix Systems UK Ltd.  (Company #02937203, SL9 0BG)
>>>> 
>>>> _______________________________________________
>>>> Xen-devel mailing list
>>>> Xen-devel@lists.xensource.com
>>>> http://lists.xensource.com/xen-devel
>> 
>>