Messages in this thread | | | Date | Thu, 11 Mar 2010 15:41:24 -0800 | From | Andrew Morton <> | Subject | Re: [RFC PATCH 0/3] Avoid the use of congestion_wait under zone pressure |
| |
On Mon, 8 Mar 2010 11:48:20 +0000 Mel Gorman <mel@csn.ul.ie> wrote:
> Under memory pressure, the page allocator and kswapd can go to sleep using > congestion_wait(). In two of these cases, it may not be the appropriate > action as congestion may not be the problem.
clear_bdi_congested() is called each time a write completes and the queue is below the congestion threshold.
So if the page allocator or kswapd call congestion_wait() against a non-congested queue, they'll wake up on the very next write completion.
Hence the above-quoted claim seems to me to be a significant mis-analysis and perhaps explains why the patchset didn't seem to help anything?
| |