On Fri, Jan 03, 2020 at 11:24:20AM +0100, Petr Mladek wrote:
> On Mon 2019-12-23 17:01:00, John Ogness wrote:
> > Hi Andrea,
> >
> > On 2019-12-21, Andrea Parri wrote:
> > >> +*desc_out = READ_ONCE(*desc);
> > >> +
> > >> +/* Load data before re-checking state. */
> > >> +
On Mon 2019-12-23 17:01:00, John Ogness wrote:
> Hi Andrea,
>
> On 2019-12-21, Andrea Parri wrote:
> >> + *desc_out = READ_ONCE(*desc);
> >> +
> >> + /* Load data before re-checking state. */
> >> + smp_rmb(); /* matches LMM_REF(desc_reserve:A) */
> >
> > I looked for a matching WRITE_ONCE()
Hi Andrea,
On 2019-12-21, Andrea Parri wrote:
>> +*desc_out = READ_ONCE(*desc);
>> +
>> +/* Load data before re-checking state. */
>> +smp_rmb(); /* matches LMM_REF(desc_reserve:A) */
>
> I looked for a matching WRITE_ONCE() or some other type of marked write,
> but I could not find
Hi John,
Sorry for the delay.
I don't have an overall understanding of the patch(-set) yet, so I limit
to a couple of general questions about the memory barriers introduced by
the path. Please see inline comments.
> + *desc_out = READ_ONCE(*desc);
> +
> + /* Load data before
On 2019-12-09, Sergey Senozhatsky wrote:
>> + * Sample reader code::
>> + *
>> + * struct printk_info info;
>> + * char text_buf[32];
>> + * char dict_buf[32];
>> + * u64 next_seq = 0;
>> + * struct printk_record r = {
>> + * .info = ,
>> + * .text_buf =
On (19/11/28 02:58), John Ogness wrote:
> + * Sample reader code::
> + *
> + * struct printk_info info;
> + * char text_buf[32];
> + * char dict_buf[32];
> + * u64 next_seq = 0;
> + * struct printk_record r = {
> + * .info = ,
> + * .text_buf =
On (19/12/02 16:48), Petr Mladek wrote:
> Hi,
>
> I have seen few prelimitary versions before this public one.
> I am either happy with it or blind to see new problems[*].
I guess I'm happy with it.
-ss
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On 2019-12-09, Sergey Senozhatsky wrote:
>> +#define _DATA_SIZE(sz_bits) (1UL << (sz_bits))
>> +#define _DESCS_COUNT(ct_bits) (1U << (ct_bits))
>> +#define DESC_SV_BITS(sizeof(int) * 8)
>> +#define DESC_COMMITTED_MASK (1U << (DESC_SV_BITS -
On (19/11/28 02:58), John Ogness wrote:
[..]
> +
> +#define _DATA_SIZE(sz_bits) (1UL << (sz_bits))
> +#define _DESCS_COUNT(ct_bits)(1U << (ct_bits))
> +#define DESC_SV_BITS (sizeof(int) * 8)
> +#define DESC_COMMITTED_MASK (1U << (DESC_SV_BITS - 1))
On 2019-12-03, Steven Rostedt wrote:
> +/* Reserve a new descriptor, invalidating the oldest if necessary. */
> +static bool desc_reserve(struct printk_ringbuffer *rb, u32 *id_out)
> +{
> + struct prb_desc_ring *desc_ring = >desc_ring;
> + struct prb_desc *desc;
> + u32
On Tue 2019-12-03 15:13:36, John Ogness wrote:
> On 2019-12-02, Petr Mladek wrote:
> >> +/*
> >> + * Sanity checker for reserve size. The ringbuffer code assumes that a
> >> data
> >> + * block does not exceed the maximum possible size that could fit within
> >> the
> >> + * ringbuffer. This
On Tue, 3 Dec 2019 10:17:21 +0900
Sergey Senozhatsky wrote:
> > > BTW: If I am counting correctly. The ABA problem would happen when
> > > exactly 2^30 (1G) messages is written in the mean time.
> >
> > All the ringbuffer code assumes that the use of index numbers handles
> > the ABA problem
On 2019-12-02, Petr Mladek wrote:
>> +/*
>> + * Sanity checker for reserve size. The ringbuffer code assumes that a data
>> + * block does not exceed the maximum possible size that could fit within the
>> + * ringbuffer. This function provides that basic size check so that the
>> + * assumption
On Mon 2019-12-02 17:37:26, John Ogness wrote:
> On 2019-12-02, Petr Mladek wrote:
> >> > +/* Reserve a new descriptor, invalidating the oldest if necessary. */
> >> > +static bool desc_reserve(struct printk_ringbuffer *rb, u32 *id_out)
> >> > +{
> >> > +struct prb_desc_ring *desc_ring =
On (19/12/02 17:37), John Ogness wrote:
> On 2019-12-02, Petr Mladek wrote:
> >> > +/* Reserve a new descriptor, invalidating the oldest if necessary. */
> >> > +static bool desc_reserve(struct printk_ringbuffer *rb, u32 *id_out)
> >> > +{
> >> > +struct prb_desc_ring *desc_ring =
On 2019-12-02, Petr Mladek wrote:
>> > +/* Reserve a new descriptor, invalidating the oldest if necessary. */
>> > +static bool desc_reserve(struct printk_ringbuffer *rb, u32 *id_out)
>> > +{
>> > + struct prb_desc_ring *desc_ring = >desc_ring;
>> > + struct prb_desc *desc;
>> > + u32
On Mon 2019-12-02 16:48:41, Petr Mladek wrote:
> > +/* Reserve a new descriptor, invalidating the oldest if necessary. */
> > +static bool desc_reserve(struct printk_ringbuffer *rb, u32 *id_out)
> > +{
> > + struct prb_desc_ring *desc_ring = >desc_ring;
> > + struct prb_desc *desc;
> > + u32
Hi,
I have seen few prelimitary versions before this public one.
I am either happy with it or blind to see new problems[*].
It would be great if anyone else could look at it. Especially
I am intreseted:
+ Whether the algorithm can be understood by people who
see it for the "first" time.
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