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Rockbox mail archiveSubject: Re: buflib handling in picture flow pluginRe: buflib handling in picture flow plugin
From: Thomas Martitz <kugel_at_rockbox.org>
Date: Sun, 22 Feb 2015 21:31:14 +0100 Am 22.02.2015 um 21:15 schrieb Thomas Jarosch: > Hi Thomas (kugel), > > Am Sonntag, 15. Februar 2015, 23:45:48 schrieb Thomas Martitz: >> The below commit isn't necessary. >> >> buflib buffers can be passed to yielding functions just fine. Problems >> only arise if the are concurrent allocations, for example if two threads >> allocate from the same context simultaneously or if the callee does it's >> own allocations. This can't happen in the pictureflow case, it has it's >> own context and a single thread allocating from it. >> >> Therefore the problem isn't yield() itself, but possible concurrent >> buflib_alloc() calls that result from the thread switch. This is because >> compaction only ever happens on allocation (and not in a backgroud >> thread or so). >> >> Best regards. >> >> >> commit 9076b433d18b5db1a1987fe99ca7c70808f22b0e >> Author: Thomas Jarosch <tomj_at_simonv.com> >> Date: Thu Jan 1 23:45:24 2015 +0100 >> >> PictureFlow: Add move callback for buflib allocations >> >> If we don't provide a callback to buflib_alloc(), >> the buffer is always movable (to reduce fragmentation). >> >> Since we pass our buffer to functions that call yield(), >> this could lead to memory corruption on buflib compaction. >> >> Change-Id: Id1fad1822479d692551c55cb8bc87cea7b78f759 > thanks for the review. I noticed the same thing a few days after > committing it. It occupied my mind why it wasn't crashing before ;) > Do you think we should revert it or keep it? It won't hurt I guess. > > Did you have a chance to look at the other buflib changes I did? > They should be correct IMHO. > IMO, yes, it should be reverted, because adds unecessary overhead and gives the false impression that callbacks are always required. I didn't notice other problems with your buflib related commits but I maybe missed some. Do you want me to look at a particular change? Best regards. Received on 2015-02-22 Page template was last modified "Tue Sep 7 00:00:02 2021" The Rockbox Crew -- Privacy Policy |