From mboxrd@z Thu Jan 1 00:00:00 1970 From: compudj@krystal.dyndns.org (Mathieu Desnoyers) Date: Thu, 30 Apr 2009 12:03:16 -0400 Subject: [ltt-dev] [PATCH] Fix dirty page accounting in redirty_page_for_writepage() In-Reply-To: <20090430143215.GE14696@elte.hu> References: <20090429232546.GB15782@Krystal> <20090430024303.GB19875@Krystal> <20090430133859.GB8329@elte.hu> <20090430135005.GA5922@Krystal> <20090430143215.GE14696@elte.hu> Message-ID: <20090430160316.GA12926@Krystal> * Ingo Molnar (mingo at elte.hu) wrote: > > * Mathieu Desnoyers wrote: > > > * Ingo Molnar (mingo at elte.hu) wrote: > > > > > > * Christoph Lameter wrote: > > > > > > > On Wed, 29 Apr 2009, Mathieu Desnoyers wrote: > > > > > > > > > to have a good look at the memory accounting code. We could > > > > > probably benefit of Christoph Lameter's cpu ops (using segment > > > > > registers to address per-cpu variables with atomic inc/dec) in > > > > > there. Or at least removing interrupt disabling by using preempt > > > > > disable and local_t variables for the per-cpu counters could > > > > > bring some benefit. > > > > > > > > Guess we are ready for atomic per cpu ops now that the new per cpu > > > > allocator is in? Segment register issues with the PDA are also > > > > solved right? > > > > > > it's all done, implemented and upstream already. You are a bit late > > > to the party ;-) > > > > > > Ingo > > > > Or way too early, depending on the point of view. :-) > > > > e.g. > > http://lkml.org/lkml/2008/5/30/3 > > > > I think Christoph deserves credits for pioneering this area with fresh > > ideas. > > Ok, i didnt want to go there - but let me correct this version of > history. > > Christoph's zero-based x86 percpu patches were incomplete and never > worked reliably - Christoph unfortunately never addressed the > bugs/crashes i reported. (and Mike Travis and me injected quite a > bit of testing into it) There were two failed attempts to productize > them and the patches just bitrotted for more than a year. > > Tejun on the other hand fixed those problems (four of Christoph's > patches survived more or less and were credited to Christoph) and > did more than 50 highly delicate patches of far larger complexity to > solve the _whole_ problem range - within a two months timeframe. > > Ideas and half-done patches covering <10% of the work needed are not > enough. Being able to implement it and productize it is the real > deal, in my book. > > Thanks goes to Christoph (and Rusty) for coming up with the idea, > but it would be manifestly unfair to not send 90% of the kudos to > Tejun for turning it all into reality and fixing all the other > problems and redesigning almost all the x86 percpu code in the > process! ;-) > Then thanks to Christoph, Rusty and to Tejun for the respective effort they did. My goal is surely only to recognise their respective credit. Mathieu > Ingo > > _______________________________________________ > ltt-dev mailing list > ltt-dev at lists.casi.polymtl.ca > http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev > -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68