On 05/14/2012 07:58 AM, ehrhardt@xxxxxxxxxxxxxxxxxx wrote:
From: Christian Ehrhardt<ehrhardt@xxxxxxxxxxxxxxxxxx> Swap readahead works fine, but the I/O to disk is almost always done in page size requests, despite the fact that readahead submits 1<<page-cluster pages at a time. On older kernels the old per device plugging behavior might have captured this and merged the requests, but currently all comes down to much more I/Os than required. On a single device this might not be an issue, but as soon as a server runs on shared san resources savin I/Os not only improves swapin throughput but also provides a lower resource utilization.
Signed-off-by: Christian Ehrhardt<ehrhardt@xxxxxxxxxxxxxxxxxx>
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