On Wed, Jan 11, 2012 at 02:30:44PM -0500, Rik van Riel wrote: > Ever since abandoning the virtual scan of processes, for scalability > reasons, swap space has been a little more fragmented than before. > This can lead to the situation where a large memory user is killed, > swap space ends up full of "holes" and swapin readahead is totally > ineffective. > > On my home system, after killing a leaky firefox it took over an > hour to page just under 2GB of memory back in, slowing the virtual > machines down to a crawl. > > This patch makes swapin readahead simply skip over holes, instead > of stopping at them. This allows the system to swap things back in > at rates of several MB/second, instead of a few hundred kB/second. > > The checks done in valid_swaphandles are already done in > read_swap_cache_async as well, allowing us to remove a fair amount > of code. __swap_duplicate() also checks for whether the offset is within the swap device range. Do you think we could remove get_swap_cluster() altogether and just try reading the aligned page_cluster range? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>