On 07/25/2010 11:08 PM, Wu Fengguang wrote:
We do need some throttling under memory pressure. However stall time more than 1s is not acceptable. A simple congestion_wait() may be better, since it waits on _any_ IO completion (which will likely release a set of PG_reclaim pages) rather than one specific IO completion. This makes much smoother stall time. wait_on_page_writeback() shall really be the last resort. DEF_PRIORITY/3 means 1/16=6.25%, which is closer.
I agree with the max 1 second stall time, but 6.25% of memory could be an awful lot of pages to scan on a system with 1TB of memory :) Not sure what the best approach is, just pointing out that DEF_PRIORITY/3 may be too much for large systems... -- All rights reversed -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
