Messages in this thread | | | Date | Mon, 09 Jan 2012 18:49:51 -0500 | From | KOSAKI Motohiro <> | Subject | Re: [PATCH -mm] make swapin readahead skip over holes |
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(1/9/12 6:10 PM), 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.
If I understand correctly, this patch have
Pros - increase IO throughput Cons - increase a risk to pick up unrelated swap entries by swap readahead
The changelog explained former but doesn't explained latter. I'm a bit hesitate now.
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