Re: Move PinBuffer and UnpinBuffer to atomics

Hi!

On Thu, Mar 31, 2016 at 4:59 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
wrote:

> On Tue, Mar 29, 2016 at 10:52 PM, Alexander Korotkov <
> a(dot)korotkov(at)postgrespro(dot)ru> wrote:
>
>> Hi, Andres!
>>
>> Please, find next revision of patch in attachment.
>>
>>
> Couple of minor comments:
>
> + * The following two macroses
>
> is macroses right word to be used here?
>
> + * of this loop. It should be used as fullowing:
>
> /fullowing/following
>
> + * For local buffers usage of these macros shouldn't be used.
>
> isn't it better to write it as
>
> For local buffers, these macros shouldn't be used.
>
>
> static int ts_ckpt_progress_comparator(Datum a, Datum b, void *arg);
>
> -
>
> Spurious line deletion.
>

All of above is fixed.

+ * Since buffers are pinned/unpinned very frequently, this functions tries
> + * to pin buffer as cheap as possible.
>
> /this functions tries
>
> which functions are you referring here? Comment seems to be slightly
> unclear.
>

I meant just PinBuffer() there. UnpinBuffer() has another comment in the
body. Fixed.

> ! if (XLogHintBitIsNeeded() && (pg_atomic_read_u32(&bufHdr->state) &
> BM_PERMANENT))
>
> Is there a reason that you have kept macro's to read refcount and
> usagecount, but not for flags?
>

We could change dealing with flags to GET/SET macros. But I guess such
change would make review more complicated, because it would touch some
places which are unchanged for now. I think it could be done in a separate
refactoring patch.

Apart from this, I have verified that patch compiles on Windows and passed
> regressions (make check)!
>

Thank you! I didn't manage to try this on Windows.

> Nice work!
>

Thank you!

------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company