Patchwork exec.c: Fix calculation of code_gen_buffer_max_size

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Submitter Peter Maydell
Date June 22, 2011, 10:58 a.m.
Message ID <1308740305-17634-1-git-send-email-peter.maydell@linaro.org>
Download mbox | patch
Permalink /patch/101432/
State New
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Comments

Peter Maydell - June 22, 2011, 10:58 a.m.
When calculating the point at which we should not try to put another
TB into the code gen buffer, we have to allow not just for OPC_MAX_SIZE
but OPC_BUF_SIZE. This is because the target translate.c will only
stop when an instruction has put it past the OPC_MAX_SIZE limit, so
we have to include the MAX_OP_PER_INSTR margin which that final insn
might have used.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 exec.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
Peter Maydell - July 6, 2011, 11:07 a.m.
Ping?

On 22 June 2011 11:58, Peter Maydell <peter.maydell@linaro.org> wrote:
> When calculating the point at which we should not try to put another
> TB into the code gen buffer, we have to allow not just for OPC_MAX_SIZE
> but OPC_BUF_SIZE. This is because the target translate.c will only
> stop when an instruction has put it past the OPC_MAX_SIZE limit, so
> we have to include the MAX_OP_PER_INSTR margin which that final insn
> might have used.
>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  exec.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/exec.c b/exec.c
> index 09928a3..c910840 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -555,8 +555,8 @@ static void code_gen_alloc(unsigned long tb_size)
>  #endif
>  #endif /* !USE_STATIC_CODE_GEN_BUFFER */
>     map_exec(code_gen_prologue, sizeof(code_gen_prologue));
> -    code_gen_buffer_max_size = code_gen_buffer_size -
> -        (TCG_MAX_OP_SIZE * OPC_MAX_SIZE);
> +    code_gen_buffer_max_size = code_gen_buffer_size -
> +        (TCG_MAX_OP_SIZE * OPC_BUF_SIZE);
>     code_gen_max_blocks = code_gen_buffer_size / CODE_GEN_AVG_BLOCK_SIZE;
>     tbs = qemu_malloc(code_gen_max_blocks * sizeof(TranslationBlock));
>  }
> --
> 1.7.1
Blue Swirl - July 12, 2011, 8:52 p.m.
Thanks, applied.

On Wed, Jul 6, 2011 at 2:07 PM, Peter Maydell <peter.maydell@linaro.org> wrote:
> Ping?
>
> On 22 June 2011 11:58, Peter Maydell <peter.maydell@linaro.org> wrote:
>> When calculating the point at which we should not try to put another
>> TB into the code gen buffer, we have to allow not just for OPC_MAX_SIZE
>> but OPC_BUF_SIZE. This is because the target translate.c will only
>> stop when an instruction has put it past the OPC_MAX_SIZE limit, so
>> we have to include the MAX_OP_PER_INSTR margin which that final insn
>> might have used.
>>
>> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
>> ---
>>  exec.c |    4 ++--
>>  1 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/exec.c b/exec.c
>> index 09928a3..c910840 100644
>> --- a/exec.c
>> +++ b/exec.c
>> @@ -555,8 +555,8 @@ static void code_gen_alloc(unsigned long tb_size)
>>  #endif
>>  #endif /* !USE_STATIC_CODE_GEN_BUFFER */
>>     map_exec(code_gen_prologue, sizeof(code_gen_prologue));
>> -    code_gen_buffer_max_size = code_gen_buffer_size -
>> -        (TCG_MAX_OP_SIZE * OPC_MAX_SIZE);
>> +    code_gen_buffer_max_size = code_gen_buffer_size -
>> +        (TCG_MAX_OP_SIZE * OPC_BUF_SIZE);
>>     code_gen_max_blocks = code_gen_buffer_size / CODE_GEN_AVG_BLOCK_SIZE;
>>     tbs = qemu_malloc(code_gen_max_blocks * sizeof(TranslationBlock));
>>  }
>> --
>> 1.7.1
>
>

Patch

diff --git a/exec.c b/exec.c
index 09928a3..c910840 100644
--- a/exec.c
+++ b/exec.c
@@ -555,8 +555,8 @@  static void code_gen_alloc(unsigned long tb_size)
 #endif
 #endif /* !USE_STATIC_CODE_GEN_BUFFER */
     map_exec(code_gen_prologue, sizeof(code_gen_prologue));
-    code_gen_buffer_max_size = code_gen_buffer_size - 
-        (TCG_MAX_OP_SIZE * OPC_MAX_SIZE);
+    code_gen_buffer_max_size = code_gen_buffer_size -
+        (TCG_MAX_OP_SIZE * OPC_BUF_SIZE);
     code_gen_max_blocks = code_gen_buffer_size / CODE_GEN_AVG_BLOCK_SIZE;
     tbs = qemu_malloc(code_gen_max_blocks * sizeof(TranslationBlock));
 }