Re: [gentoo-dev] Multiple emerges in parallel (was: [RFC] RESTRICT=parallel for builds that can't be executed in parallel)

["Michał Górny" <gentoo@mgorny.alt.pl>]

[-- Attachment #1: Type: text/plain, Size: 1469 bytes --]

On Wed, 14 Apr 2010 11:10:29 -0700
Brian Harring <ferringb@gmail.com> wrote:

> Running multiple emerge's in parallel is unsafe due to the fact 
> they've got two potentially very different plans as to what is being 
> done, and that there is no possibility to ensure that pkg D that PM-2 
> is building isn't affected by PM-1 building something (upgrading a 
> dependency of pkg D for example).
> 
> Yes you can get away with it occasionally, that doesn't mean it's 
> safe however.

I agree with you -- such operations should be performed with
appropriate caution, on user's own responsibility. But this doesn't
mean we should prevent user from being able to do that.

> Aborting merges is a very, very bad idea.  Consider a pkg that has 
> dlopen'd plugins, and just went through an ABI change for that 
> interface.  If you interupt that merge it's entirely possible you'll 
> get just the lib merged (meaning a segfault on loadup of the
> plugins), or vice versa (old lib is still in place, but new plugins
> are there).
> 
> Don't abort merges- that really should be effectively an atomic OP, 
> not interuptible.

Sorry, by 'aborting merges' I meant rather aborting the build process
before the 'merge' phase -- or even aborting it before it is started
(i.e. before it unpacks a load of files into ${PORTAGE_TMPDIR}
without sufficient space).

-- 
Best regards,
Michał Górny

<http://mgorny.alt.pl>
<xmpp:mgorny@jabber.ru>

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 198 bytes --]