Messages in this thread | | | Date | Wed, 14 Oct 2009 17:50:52 +0100 | From | Mel Gorman <> | Subject | Re: [Bug #14141] order 2 page allocation failures in iwlagn |
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On Wed, Oct 14, 2009 at 09:28:00AM -0700, reinette chatre wrote: > Hi Mel, > > On Wed, 2009-10-14 at 03:30 -0700, Mel Gorman wrote: > > From 5fb9f897117bf2701f9fdebe4d008dbe34358ab9 Mon Sep 17 00:00:00 2001 > > From: Mel Gorman <mel@csn.ul.ie> > > Date: Wed, 14 Oct 2009 11:19:57 +0100 > > Subject: [PATCH] iwlwifi: Suppress warnings related to GFP_ATOMIC allocations that do not matter > > > > iwlwifi refills RX buffers in two ways - a direct method using GFP_ATOMIC > > and a tasklet method using GFP_KERNEL. There are a number of RX buffers and > > there are only serious issues when there are no RX buffers left. The driver > > explicitly warns when refills are failing and the buffers are low but it > > always warns when a GFP_ATOMIC allocation fails even when there is no > > packet loss as a result. > > > No, it does not always warn when a GFP_ATOMIC allocation fails. Please > check earlier in iwl_rx_allocate() we have: > > if (rxq->free_count > RX_LOW_WATERMARK) > priority |= __GFP_NOWARN; > > So it will suppress warnings as long as we have buffers available. > > We do want to see warnings if memory is below watermark and allocation > fails - your patch prevents these warnings from appearing. >
Yeah, the patch is balls and is not the way forward.
What is your take on GFP_ATOMIC-direct deleting the pool before the tasklet can refill it with GFP_KERNEL? Should direct allocation be falling back to calling with GFP_KERNEL when the pool has been depleted instead of failing?
-- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab
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