Messages in this thread | | | Subject | RE: [PATCH] mm: moving dirty pages balancing to pdfludh entirely | Date | Wed, 5 Jul 2006 19:48:39 +0400 | From | "Ananiev, Leonid I" <> |
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Nikita Danilov writes: > What about replacing > pdflush_operation(background_writeout, 0); > with > if (pdflush_operation(background_writeout, 0)) > > writeback_inodes(&wbc); The is a latency betwean pdflush_operation() call and writeback_in_progress(bdi) returns true. As a result writeback_inodes() may be called in next loop before pdflush is started. Pdflush detects that writeback_in_progress() returns true for it and will exit.
Leonid -----Original Message----- From: Nikita Danilov [mailto:nikita@clusterfs.com] Sent: Wednesday, July 05, 2006 6:57 PM To: Ananiev, Leonid I Cc: Linux Kernel Mailing List Subject: Re: [PATCH] mm: moving dirty pages balancing to pdfludh entirely
Ananiev, Leonid I writes: > Nikita Danilov writes: > > suppose you have more than MAX_PDFLUSH_THREADS > Do you consider that the drawback of the patch is in that the value > MAX_PDFLUSH_THREADS is not well known high or this limit is not deleted
I am more concerned, that this patch _limits_ maximal possible writeback concurrency to MAX_PDFLUSH_THREADS.
> at all? The limit could be deleted after patching because the line
That sounds a bit too extreme, given that pdflush is used for a lot of things other than background write-out.
> + if (writeback_in_progress(bdi)) { > keeps off creating extra pdflush threads.
What about replacing
pdflush_operation(background_writeout, 0);
with
if (pdflush_operation(background_writeout, 0)) /* * Fall back to synchronous writeback if all pdflush * threads are busy. */ writeback_inodes(&wbc);
? This will combine increased concurrency in your target case (single writer) with some safety net in the case of multiple writers and multiple devices.
> > Leonid
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