Displaying 8 results from an estimated 8 matches for "warn_single_copy_align".
2016 Nov 25
2
[PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE()
On Fri, Nov 25, 2016 at 01:40:44PM +0100, Peter Zijlstra wrote:
> #define SINGLE_LOAD(x) \
> {( \
> compiletime_assert_atomic_type(typeof(x)); \
Should be:
compiletime_assert_atomic_type(x);
> WARN_SINGLE_COPY_ALIGNMENT(&(x)); \
> READ_ONCE(x); \
> })
>
> #define SINGLE_STORE(x, v) \
> ({ \
> compiletime_assert_atomic_type(typeof(x)); \
idem
> WARN_SINGLE_COPY_ALIGNMENT(&(x)); \
> WRITE_ONCE(x, v); \
> })
2016 Nov 25
2
[PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE()
On Fri, Nov 25, 2016 at 01:40:44PM +0100, Peter Zijlstra wrote:
> #define SINGLE_LOAD(x) \
> {( \
> compiletime_assert_atomic_type(typeof(x)); \
Should be:
compiletime_assert_atomic_type(x);
> WARN_SINGLE_COPY_ALIGNMENT(&(x)); \
> READ_ONCE(x); \
> })
>
> #define SINGLE_STORE(x, v) \
> ({ \
> compiletime_assert_atomic_type(typeof(x)); \
idem
> WARN_SINGLE_COPY_ALIGNMENT(&(x)); \
> WRITE_ONCE(x, v); \
> })
2016 Nov 25
3
[PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE()
On Fri, Nov 25, 2016 at 12:33:48PM +0100, Christian Borntraeger wrote:
> On 11/25/2016 12:22 PM, Mark Rutland wrote:
> > On Thu, Nov 24, 2016 at 10:36:58PM +0200, Michael S. Tsirkin wrote:
> >> Though I really question the whole _ONCE APIs esp with
> >> aggregate types - these seem to generate a memcpy and
> >> an 8-byte read/writes sometimes, and I'm pretty
2016 Nov 25
3
[PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE()
On Fri, Nov 25, 2016 at 12:33:48PM +0100, Christian Borntraeger wrote:
> On 11/25/2016 12:22 PM, Mark Rutland wrote:
> > On Thu, Nov 24, 2016 at 10:36:58PM +0200, Michael S. Tsirkin wrote:
> >> Though I really question the whole _ONCE APIs esp with
> >> aggregate types - these seem to generate a memcpy and
> >> an 8-byte read/writes sometimes, and I'm pretty
2016 Nov 25
0
[PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE()
...roblematic; calling them ATOMIC_* makes tham sound like
> they work on atomic_t. That and I have no idea how to ensure correct
> usage tree-wide; I'm not sure if/how Coccinelle can help.
>
> Peter, thoughts?
Something like so perhaps?
---
#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
#define WARN_SINGLE_COPY_ALIGNMENT(ptr) \
WARN_ON_ONCE(((unsigned long)(ptr)) & (sizeof(*(ptr))-1))
#else
#define WARN_SINGLE_COPY_ALIGNMENT(ptr)
#endif
/*
* Provide accessors for Single-Copy atomicy.
*
* That is, ensure that machine word sized loads/stores to naturally
* aligned variables are single instructions.
*...
2016 Nov 25
0
[PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE()
...00, Peter Zijlstra wrote:
> On Fri, Nov 25, 2016 at 01:40:44PM +0100, Peter Zijlstra wrote:
> > #define SINGLE_LOAD(x) \
> > {( \
> > compiletime_assert_atomic_type(typeof(x)); \
>
> Should be:
>
> compiletime_assert_atomic_type(x);
>
> > WARN_SINGLE_COPY_ALIGNMENT(&(x)); \
Do we need to worry about the side effect on x? Maybe
#define SINGLE_LOAD(x) \
({ \
typeof(x) *_____ptr; \
\
compiletime_assert_atomic_type(typeof(x)); \
\
_____ptr = &(x); \
\
WARN_SINGLE_COPY_ALIGNMENT(_____ptr); \
\
READ_...
2016 Nov 25
2
[PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE()
...\
>> > {( \
>> > compiletime_assert_atomic_type(typeof(x)); \
>>
>> Should be:
>>
>> compiletime_assert_atomic_type(x);
>>
>> > WARN_SINGLE_COPY_ALIGNMENT(&(x)); \
>
> Do we need to worry about the side effect on x? Maybe
>
> #define SINGLE_LOAD(x) \
> ({ \
> typeof(x) *_____ptr; \
&g...
2016 Nov 25
2
[PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE()
...\
>> > {( \
>> > compiletime_assert_atomic_type(typeof(x)); \
>>
>> Should be:
>>
>> compiletime_assert_atomic_type(x);
>>
>> > WARN_SINGLE_COPY_ALIGNMENT(&(x)); \
>
> Do we need to worry about the side effect on x? Maybe
>
> #define SINGLE_LOAD(x) \
> ({ \
> typeof(x) *_____ptr; \
&g...