William Lee Irwin III wrote:
>
> Jens Axboe wrote:
> >> GFP_NOIO has __GFP_WAIT set, so bio_copy -> bio_alloc -> mempool_alloc
> >> should never fail. Puzzled.
>
> On Tue, Jul 16, 2002 at 01:52:40AM -0700, Andrew Morton wrote:
> > Presumably the loop driver was called from within shrink_cache(),
> > as PF_MEMALLOC. Those allocations can fail.
> > That's maybe wrong - if there are a decent number of pages
> > under writeback then we should be able to just wait it out.
> > But it gets tricky with the loop driver...
>
> I included a backtrace in my original post showing that the allocation
> failure did indeed occur beneath shrink_cache().
>
> >From watching /proc/meminfo it was clear that there were only 1MB or
> 2MB under writeback, but it also showed that the dirty memory thresholds
> were being exceeded.
Ah, that may well happen with loop. Mark a page clean, "submit"
it and that just goes and marks a different page dirty.
If you could please share the setup details (amount of memory,
file sizes, workload etc) I'll have a look.
btw, Jens: where do the pages which bio_copy allocates get freed?
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This archive was generated by hypermail 2b29 : Tue Jul 23 2002 - 22:00:19 EST