diff mbox

[RFC,v7,01/16] exec.c: Add new exclusive bitmap to ram_list

Message ID 1454059965-23402-2-git-send-email-a.rigo@virtualopensystems.com (mailing list archive)
State New, archived
Headers show

Commit Message

alvise rigo Jan. 29, 2016, 9:32 a.m. UTC
The purpose of this new bitmap is to flag the memory pages that are in
the middle of LL/SC operations (after a LL, before a SC). For all these
pages, the corresponding TLB entries will be generated in such a way to
force the slow-path for all the VCPUs (see the following patches).

When the system starts, the whole memory is set to dirty.

Suggested-by: Jani Kokkonen <jani.kokkonen@huawei.com>
Suggested-by: Claudio Fontana <claudio.fontana@huawei.com>
Signed-off-by: Alvise Rigo <a.rigo@virtualopensystems.com>
---
 exec.c                  |  7 +++++--
 include/exec/memory.h   |  3 ++-
 include/exec/ram_addr.h | 31 +++++++++++++++++++++++++++++++
 3 files changed, 38 insertions(+), 3 deletions(-)

Comments

Alex Bennée Feb. 11, 2016, 1 p.m. UTC | #1
Alvise Rigo <a.rigo@virtualopensystems.com> writes:

> The purpose of this new bitmap is to flag the memory pages that are in
> the middle of LL/SC operations (after a LL, before a SC). For all these
> pages, the corresponding TLB entries will be generated in such a way to
> force the slow-path for all the VCPUs (see the following patches).
>
> When the system starts, the whole memory is set to dirty.
>
> Suggested-by: Jani Kokkonen <jani.kokkonen@huawei.com>
> Suggested-by: Claudio Fontana <claudio.fontana@huawei.com>
> Signed-off-by: Alvise Rigo <a.rigo@virtualopensystems.com>
> ---
>  exec.c                  |  7 +++++--
>  include/exec/memory.h   |  3 ++-
>  include/exec/ram_addr.h | 31 +++++++++++++++++++++++++++++++
>  3 files changed, 38 insertions(+), 3 deletions(-)
>
> diff --git a/exec.c b/exec.c
> index 7115403..51f366d 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -1575,11 +1575,14 @@ static ram_addr_t ram_block_add(RAMBlock *new_block, Error **errp)
>          int i;
>
>          /* ram_list.dirty_memory[] is protected by the iothread lock.  */
> -        for (i = 0; i < DIRTY_MEMORY_NUM; i++) {
> +        for (i = 0; i < DIRTY_MEMORY_EXCLUSIVE; i++) {
>              ram_list.dirty_memory[i] =
>                  bitmap_zero_extend(ram_list.dirty_memory[i],
>                                     old_ram_size, new_ram_size);
> -       }
> +        }
> +        ram_list.dirty_memory[DIRTY_MEMORY_EXCLUSIVE] =
> +            bitmap_zero_extend(ram_list.dirty_memory[DIRTY_MEMORY_EXCLUSIVE],
> +                               old_ram_size, new_ram_size);

In the previous patch you moved this out of the loop as
ram_list.dirty_memory[DIRTY_MEMORY_EXCLUSIVE] was a different size to
the other dirty bitmaps. This no longer seems to be the case so this
seems pointless.

>      }
>      cpu_physical_memory_set_dirty_range(new_block->offset,
>                                          new_block->used_length,
> diff --git a/include/exec/memory.h b/include/exec/memory.h
> index c92734a..71e0480 100644
> --- a/include/exec/memory.h
> +++ b/include/exec/memory.h
> @@ -19,7 +19,8 @@
>  #define DIRTY_MEMORY_VGA       0
>  #define DIRTY_MEMORY_CODE      1
>  #define DIRTY_MEMORY_MIGRATION 2
> -#define DIRTY_MEMORY_NUM       3        /* num of dirty bits */
> +#define DIRTY_MEMORY_EXCLUSIVE 3
> +#define DIRTY_MEMORY_NUM       4        /* num of dirty bits */
>
>  #include <stdint.h>
>  #include <stdbool.h>
> diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
> index ef1489d..19789fc 100644
> --- a/include/exec/ram_addr.h
> +++ b/include/exec/ram_addr.h
> @@ -21,6 +21,7 @@
>
>  #ifndef CONFIG_USER_ONLY
>  #include "hw/xen/xen.h"
> +#include "sysemu/sysemu.h"
>
>  struct RAMBlock {
>      struct rcu_head rcu;
> @@ -172,6 +173,9 @@ static inline void cpu_physical_memory_set_dirty_range(ram_addr_t start,
>      if (unlikely(mask & (1 << DIRTY_MEMORY_CODE))) {
>          bitmap_set_atomic(d[DIRTY_MEMORY_CODE], page, end - page);
>      }
> +    if (unlikely(mask & (1 << DIRTY_MEMORY_EXCLUSIVE))) {
> +        bitmap_set_atomic(d[DIRTY_MEMORY_EXCLUSIVE], page, end - page);
> +    }
>      xen_modified_memory(start, length);
>  }
>
> @@ -287,5 +291,32 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(unsigned long *dest,
>  }
>
>  void migration_bitmap_extend(ram_addr_t old, ram_addr_t new);
> +
> +/* Exclusive bitmap support. */
> +#define EXCL_BITMAP_GET_OFFSET(addr) (addr >> TARGET_PAGE_BITS)
> +
> +/* Make the page of @addr not exclusive. */
> +static inline void cpu_physical_memory_unset_excl(ram_addr_t addr)
> +{
> +    set_bit_atomic(EXCL_BITMAP_GET_OFFSET(addr),
> +                   ram_list.dirty_memory[DIRTY_MEMORY_EXCLUSIVE]);
> +}
> +
> +/* Return true if the page of @addr is exclusive, i.e. the EXCL bit is set. */
> +static inline int cpu_physical_memory_is_excl(ram_addr_t addr)
> +{
> +    return !test_bit(EXCL_BITMAP_GET_OFFSET(addr),
> +                     ram_list.dirty_memory[DIRTY_MEMORY_EXCLUSIVE]);
> +}
> +
> +/* Set the page of @addr as exclusive clearing its EXCL bit and return the
> + * previous bit's state. */
> +static inline int cpu_physical_memory_set_excl(ram_addr_t addr)
> +{
> +    return bitmap_test_and_clear_atomic(
> +                                ram_list.dirty_memory[DIRTY_MEMORY_EXCLUSIVE],
> +                                EXCL_BITMAP_GET_OFFSET(addr), 1);
> +}
> +
>  #endif
>  #endif


--
Alex Bennée
alvise rigo Feb. 11, 2016, 1:21 p.m. UTC | #2
You are right, the for loop with i < DIRTY_MEMORY_NUM works just fine.

Thank you,
alvise

On Thu, Feb 11, 2016 at 2:00 PM, Alex Bennée <alex.bennee@linaro.org> wrote:
>
> Alvise Rigo <a.rigo@virtualopensystems.com> writes:
>
>> The purpose of this new bitmap is to flag the memory pages that are in
>> the middle of LL/SC operations (after a LL, before a SC). For all these
>> pages, the corresponding TLB entries will be generated in such a way to
>> force the slow-path for all the VCPUs (see the following patches).
>>
>> When the system starts, the whole memory is set to dirty.
>>
>> Suggested-by: Jani Kokkonen <jani.kokkonen@huawei.com>
>> Suggested-by: Claudio Fontana <claudio.fontana@huawei.com>
>> Signed-off-by: Alvise Rigo <a.rigo@virtualopensystems.com>
>> ---
>>  exec.c                  |  7 +++++--
>>  include/exec/memory.h   |  3 ++-
>>  include/exec/ram_addr.h | 31 +++++++++++++++++++++++++++++++
>>  3 files changed, 38 insertions(+), 3 deletions(-)
>>
>> diff --git a/exec.c b/exec.c
>> index 7115403..51f366d 100644
>> --- a/exec.c
>> +++ b/exec.c
>> @@ -1575,11 +1575,14 @@ static ram_addr_t ram_block_add(RAMBlock *new_block, Error **errp)
>>          int i;
>>
>>          /* ram_list.dirty_memory[] is protected by the iothread lock.  */
>> -        for (i = 0; i < DIRTY_MEMORY_NUM; i++) {
>> +        for (i = 0; i < DIRTY_MEMORY_EXCLUSIVE; i++) {
>>              ram_list.dirty_memory[i] =
>>                  bitmap_zero_extend(ram_list.dirty_memory[i],
>>                                     old_ram_size, new_ram_size);
>> -       }
>> +        }
>> +        ram_list.dirty_memory[DIRTY_MEMORY_EXCLUSIVE] =
>> +            bitmap_zero_extend(ram_list.dirty_memory[DIRTY_MEMORY_EXCLUSIVE],
>> +                               old_ram_size, new_ram_size);
>
> In the previous patch you moved this out of the loop as
> ram_list.dirty_memory[DIRTY_MEMORY_EXCLUSIVE] was a different size to
> the other dirty bitmaps. This no longer seems to be the case so this
> seems pointless.
>
>>      }
>>      cpu_physical_memory_set_dirty_range(new_block->offset,
>>                                          new_block->used_length,
>> diff --git a/include/exec/memory.h b/include/exec/memory.h
>> index c92734a..71e0480 100644
>> --- a/include/exec/memory.h
>> +++ b/include/exec/memory.h
>> @@ -19,7 +19,8 @@
>>  #define DIRTY_MEMORY_VGA       0
>>  #define DIRTY_MEMORY_CODE      1
>>  #define DIRTY_MEMORY_MIGRATION 2
>> -#define DIRTY_MEMORY_NUM       3        /* num of dirty bits */
>> +#define DIRTY_MEMORY_EXCLUSIVE 3
>> +#define DIRTY_MEMORY_NUM       4        /* num of dirty bits */
>>
>>  #include <stdint.h>
>>  #include <stdbool.h>
>> diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
>> index ef1489d..19789fc 100644
>> --- a/include/exec/ram_addr.h
>> +++ b/include/exec/ram_addr.h
>> @@ -21,6 +21,7 @@
>>
>>  #ifndef CONFIG_USER_ONLY
>>  #include "hw/xen/xen.h"
>> +#include "sysemu/sysemu.h"
>>
>>  struct RAMBlock {
>>      struct rcu_head rcu;
>> @@ -172,6 +173,9 @@ static inline void cpu_physical_memory_set_dirty_range(ram_addr_t start,
>>      if (unlikely(mask & (1 << DIRTY_MEMORY_CODE))) {
>>          bitmap_set_atomic(d[DIRTY_MEMORY_CODE], page, end - page);
>>      }
>> +    if (unlikely(mask & (1 << DIRTY_MEMORY_EXCLUSIVE))) {
>> +        bitmap_set_atomic(d[DIRTY_MEMORY_EXCLUSIVE], page, end - page);
>> +    }
>>      xen_modified_memory(start, length);
>>  }
>>
>> @@ -287,5 +291,32 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(unsigned long *dest,
>>  }
>>
>>  void migration_bitmap_extend(ram_addr_t old, ram_addr_t new);
>> +
>> +/* Exclusive bitmap support. */
>> +#define EXCL_BITMAP_GET_OFFSET(addr) (addr >> TARGET_PAGE_BITS)
>> +
>> +/* Make the page of @addr not exclusive. */
>> +static inline void cpu_physical_memory_unset_excl(ram_addr_t addr)
>> +{
>> +    set_bit_atomic(EXCL_BITMAP_GET_OFFSET(addr),
>> +                   ram_list.dirty_memory[DIRTY_MEMORY_EXCLUSIVE]);
>> +}
>> +
>> +/* Return true if the page of @addr is exclusive, i.e. the EXCL bit is set. */
>> +static inline int cpu_physical_memory_is_excl(ram_addr_t addr)
>> +{
>> +    return !test_bit(EXCL_BITMAP_GET_OFFSET(addr),
>> +                     ram_list.dirty_memory[DIRTY_MEMORY_EXCLUSIVE]);
>> +}
>> +
>> +/* Set the page of @addr as exclusive clearing its EXCL bit and return the
>> + * previous bit's state. */
>> +static inline int cpu_physical_memory_set_excl(ram_addr_t addr)
>> +{
>> +    return bitmap_test_and_clear_atomic(
>> +                                ram_list.dirty_memory[DIRTY_MEMORY_EXCLUSIVE],
>> +                                EXCL_BITMAP_GET_OFFSET(addr), 1);
>> +}
>> +
>>  #endif
>>  #endif
>
>
> --
> Alex Bennée
diff mbox

Patch

diff --git a/exec.c b/exec.c
index 7115403..51f366d 100644
--- a/exec.c
+++ b/exec.c
@@ -1575,11 +1575,14 @@  static ram_addr_t ram_block_add(RAMBlock *new_block, Error **errp)
         int i;
 
         /* ram_list.dirty_memory[] is protected by the iothread lock.  */
-        for (i = 0; i < DIRTY_MEMORY_NUM; i++) {
+        for (i = 0; i < DIRTY_MEMORY_EXCLUSIVE; i++) {
             ram_list.dirty_memory[i] =
                 bitmap_zero_extend(ram_list.dirty_memory[i],
                                    old_ram_size, new_ram_size);
-       }
+        }
+        ram_list.dirty_memory[DIRTY_MEMORY_EXCLUSIVE] =
+            bitmap_zero_extend(ram_list.dirty_memory[DIRTY_MEMORY_EXCLUSIVE],
+                               old_ram_size, new_ram_size);
     }
     cpu_physical_memory_set_dirty_range(new_block->offset,
                                         new_block->used_length,
diff --git a/include/exec/memory.h b/include/exec/memory.h
index c92734a..71e0480 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -19,7 +19,8 @@ 
 #define DIRTY_MEMORY_VGA       0
 #define DIRTY_MEMORY_CODE      1
 #define DIRTY_MEMORY_MIGRATION 2
-#define DIRTY_MEMORY_NUM       3        /* num of dirty bits */
+#define DIRTY_MEMORY_EXCLUSIVE 3
+#define DIRTY_MEMORY_NUM       4        /* num of dirty bits */
 
 #include <stdint.h>
 #include <stdbool.h>
diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
index ef1489d..19789fc 100644
--- a/include/exec/ram_addr.h
+++ b/include/exec/ram_addr.h
@@ -21,6 +21,7 @@ 
 
 #ifndef CONFIG_USER_ONLY
 #include "hw/xen/xen.h"
+#include "sysemu/sysemu.h"
 
 struct RAMBlock {
     struct rcu_head rcu;
@@ -172,6 +173,9 @@  static inline void cpu_physical_memory_set_dirty_range(ram_addr_t start,
     if (unlikely(mask & (1 << DIRTY_MEMORY_CODE))) {
         bitmap_set_atomic(d[DIRTY_MEMORY_CODE], page, end - page);
     }
+    if (unlikely(mask & (1 << DIRTY_MEMORY_EXCLUSIVE))) {
+        bitmap_set_atomic(d[DIRTY_MEMORY_EXCLUSIVE], page, end - page);
+    }
     xen_modified_memory(start, length);
 }
 
@@ -287,5 +291,32 @@  uint64_t cpu_physical_memory_sync_dirty_bitmap(unsigned long *dest,
 }
 
 void migration_bitmap_extend(ram_addr_t old, ram_addr_t new);
+
+/* Exclusive bitmap support. */
+#define EXCL_BITMAP_GET_OFFSET(addr) (addr >> TARGET_PAGE_BITS)
+
+/* Make the page of @addr not exclusive. */
+static inline void cpu_physical_memory_unset_excl(ram_addr_t addr)
+{
+    set_bit_atomic(EXCL_BITMAP_GET_OFFSET(addr),
+                   ram_list.dirty_memory[DIRTY_MEMORY_EXCLUSIVE]);
+}
+
+/* Return true if the page of @addr is exclusive, i.e. the EXCL bit is set. */
+static inline int cpu_physical_memory_is_excl(ram_addr_t addr)
+{
+    return !test_bit(EXCL_BITMAP_GET_OFFSET(addr),
+                     ram_list.dirty_memory[DIRTY_MEMORY_EXCLUSIVE]);
+}
+
+/* Set the page of @addr as exclusive clearing its EXCL bit and return the
+ * previous bit's state. */
+static inline int cpu_physical_memory_set_excl(ram_addr_t addr)
+{
+    return bitmap_test_and_clear_atomic(
+                                ram_list.dirty_memory[DIRTY_MEMORY_EXCLUSIVE],
+                                EXCL_BITMAP_GET_OFFSET(addr), 1);
+}
+
 #endif
 #endif