Messages in this thread | | | From | Mitchell Erblich <> | Subject | Simple Code change suggestion : pdflush() : clean pages in 1/2 time | Date | Wed, 8 Jul 2009 13:03:28 -0700 |
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Group,
pdflush threads clean dirty pages.
Under the past simple assumption that a greater number of page daemon threads will have the TENDENCY to clean the pages faster.
A simple change is to create 2x the number of threads within the same timeframe as before.
Thus, in mm/pdflush.c _pdflush() thread creation is done in 1/2 HZ. ( "/" or ">>" , compiler will optimize) Above 1 sec omment should also be changed.
IMO, We could do in 1/4 or 1/8 HZ, but load (backlog of dirty pages) should then be tracked and watermarks set and determine whether keep adding additional threads allows us to clean the pages faster. (Yes, did that / done that and the code is/was ... too complicated)
The 2nd part is to prevent thread creation / destruction thrashing, keep around the extra threads to handle the bursts of frees so HZ is still kept to limit exit rate.
Mitchell Erblich
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