Re: VM/VFS bug with large amount of memory and file systems?

Rik van Riel
2007-09-18T14:42:38Z

Nick Piggin wrote:
> On Tuesday 18 September 2007 03:04, Rik van Riel wrote:
>> Nick Piggin wrote:
>>> (Rik has a patch sitting in -mm I believe which would make this problem
>>> even worse, by doing even less highmem scanning in response to lowmem
>>> allocations).
>> My patch should not make any difference here, since
>> balance_pgdat() already scans the zones from high to
>> low and sets an end_zone variable that determines the
>> highest zone to scan.
>>
>> All my patch does is make sure that we do not try to
>> reclaim excessive amounts of dma or low memory when
>> a higher zone is full.
>
> Sorry, yeah I had it the wrong way around. Your patch would not
> increase the probability of this problem.
>
> We could have some logic in there to scan highmem when buffer
> heads are over limit. But that really kind of sucks in that it introduces
> some arbitrary point where reclaim behaviour completely changes...
> Adding a shrinker for buffer heads is the "logical" approach

Christoph Lameter's slab defragmenting patch set does
this. One reason Andrew has not merged that code yet
is a lack of reviewers, so I am going through it with
a fine comb and hope to have the patches reviewed by
the end of today.

Lets get this bug fixed the right way.

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