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Date: Mon, 8 Sep 2008 13:21:24 +0330
From: "hamidreza jahanjou" <hamid.jahanjou@gmail.com>
To: "Li Yu" <raise.sail@gmail.com>
Subject: Re: [PATCH] VM: Implements the swap-out page-clustering technique
Cc: linux-kernel@vger.kernel.org
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2008/9/8, Li Yu <raise.sail@gmail.com>:
> And the linear searching for whole address space of a vma is not good
> idea too, really.
>
>> +	    if (!page_allowed_in_cluster(cursor_page, ci))
>> +		continue;
>>

Thank you for the review and comments. You are right in that searching
the whole process address space is not a good idea. The idea is to
make the scan range flexible, thus normally, assuming that the code
has been well-tuned, only a very limited number of VMA's are scanned.

In general, i think that the cluster size and the scan range should be
tuned depending on the backing storage characteristics and the
low-on-memory severity. Like any VM code, this one needs tuning.

BTW, the code could be implemented much more elegantly if the VMA's
were connected using a doubly-linked list. I wonder if there are
enought other codes with the same situation to justify making it
doubly-linked.