Re: Wait free LW_SHARED acquisition - v0.2

On 01/31/2014 11:54 AM, Andres Freund wrote:
> Hi,
>
> On 2014-01-28 21:27:29 -0800, Peter Geoghegan wrote:
>> On Fri, Nov 15, 2013 at 11:47 AM, Andres Freund <andres(at)2ndquadrant(dot)com> wrote:
>>> 1) I've added an abstracted atomic ops implementation. Needs a fair
>>> amount of work, also submitted as a separate CF entry. (Patch 1 & 2)
>>
>> Commit 220b34331f77effdb46798ddd7cca0cffc1b2858 caused bitrot when
>> applying 0002-Very-basic-atomic-ops-implementation.patch. Please
>> rebase.
>
> I've pushed a rebased version of the patchset to
> http://git.postgresql.org/gitweb/?p=users/andresfreund/postgres.git
> branch rwlock contention.
> 220b34331f77effdb46798ddd7cca0cffc1b2858 actually was the small problem,
> ea9df812d8502fff74e7bc37d61bdc7d66d77a7f was the major PITA.
>
> I plan to split the atomics patch into smaller chunks before
> reposting. Imo the "Convert the PGPROC->lwWaitLink list into a dlist
> instead of open coding it." is worth being applied independently from
> the rest of the series, it simplies code and it fixes a bug...

I committed a fix for the WakeupWaiters() bug now, without the rest of
the "open coding" patch. Converting lwWaitLInk into a dlist is probably
a good idea, but seems better to fix the bug separately, for the sake of
git history if nothing else.

- Heikki