Re: some notes on a memory leak

["Gergely Gábor" <elentirmo.gilgalad-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

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Greetings!
> 
> I'd like to append a note.
> 
> NILFS has two different things about the cache usage than ordinary
> filesystems:
> 
> (1) Since the cleaner clowls over a partition, it adds new pages into a cache
>     of the block device one after another during it operates on the background.
> 
> (2) Some blocks, for example the blocks to store header information of each
>     segment, are allocated incrementally into the cache of the block device. 
>     So, bursty writes or frequent sync writes may bloat it.
>     Conversely, the turnover of buffers for files or meta data should not be 
>     higher than usual fs because a same buffer serves for a same file offset
>     even when its physical disk address changes.
> 
generally nilfs2 performs well. rtorrent triggers some error.

> I made a patch to minimize the bloat of bdev cache due to the second
> difference.
> If you are bothered with that, please test the following patch.
> From my local tests, it didn't make no remarkable difference.
I tried the patch, i see no basic difference. the fs generally works fine, but rtorrent can make it consume all memory, and not free it after exit. just as if the cache entries didn't age (well i don't know how to describe the situation better with my naive words). I have tried setting the following, with no luck:
 vm.vfs_cache_pressure = 200
and even 
 vm.drop_caches = 3 

according to docs, it should have had some effect, but neither had any (in case of rtorrent's garbage)

the "pages" cached by rtorrent can't be flushed out of cache even when rtorrent has quit. This may as well be he fault of rtorrent, but I can remember an ext3 bug that was found by an rtorrent malfunction, and still, it is not right. (other programs generally seem to release cache after some time after having been closed). If i start a hash check on a near complete dvd image in rtorrent (0.7.9 version) i can waste my ram in less than 2 minutes!

umount helps. but now i can do my works on my notebook aswell.

Best Regards:
-- 
Gergely Gábor <elentirmo.gilgalad-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

* random fortune:
Above all things, reverence yourself.

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