Re: [RFC 1/2] deactive invalidated pages

From: Minchan Kim
Date: Tue Nov 23 2010 - 18:48:55 EST


On Tue, Nov 23, 2010 at 10:48 PM, Ben Gamari <bgamari@xxxxxxxxx> wrote:
> On Tue, 23 Nov 2010 16:16:55 +0900 (JST), KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> wrote:
>> > On Sun, 21 Nov 2010 23:30:23 +0900, Minchan Kim <minchan.kim@xxxxxxxxx> wrote:
>> > >
>> > > Ben, Remain thing is to modify rsync and use
>> > > fadvise(POSIX_FADV_DONTNEED). Could you test it?
>> >
>> > Thanks a ton for the patch. Looks good. Testing as we speak.
>>
> For the record, this was a little premature. As I spoke the kernel was
> building but I still haven't had a chance to take any data. Any
> suggestions for how to determine the effect (or hopefully lack thereof)
> of rsync on the system's working set?
>
>> If possible, can you please post your rsync patch and your testcase
>> (or your rsync option + system memory size info + data size info)?
>>
> Patch coming right up.
>
> The original test case is a backup script for my home directory. rsync
> is invoked with,
>
> rsync --archive --update --progress --delete --delete-excluded
> --exclude-from=~/.backup/exclude --log-file=~/.backup/rsync.log -e ssh
> /home/ben ben@myserver:/mnt/backup/current
>
> My home directory is 120 GB with typical delta sizes of tens of
> megabytes between backups (although sometimes deltas can be gigabytes,
> after which the server has severe interactivity issues). The server is
> unfortunately quite memory constrained with only 1.5GB of memory (old
> inherited hardware). Given the size of my typical deltas, I'm worried
> that even simply walking the directory hierarchy might be enough to push
> out my working set.
>
> Looking at the rsync access pattern with strace it seems that it does
> a very good job of avoid duplicate reads which is good news for these
> patches.

Thanks for the notice. Ben.
FYI, we have a plan to change the policy as you look this thread.
Maybe It would be good than my current policy in the page.

Please recognize it. :)

>
> Cheers,
>
> - Ben
>
>
>



--
Kind regards,
Minchan Kim
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