Re: [PATCH 6/6] vmscan: Do not writeback pages in direct reclaim

Christoph Hellwig
2010-06-11T16:25:33Z

On Thu, Jun 10, 2010 at 11:17:06PM -0700, Andrew Morton wrote:
> As it stands, it would be wildly incautious to make a change like
> this without first working out why we're pulling so many dirty pages
> off the LRU tail, and fixing that.

Note that unlike the writepage vs writepages from kswapd which can
be fixed by the right tuning this is a black or white issue. Writeback
from direct reclaim will kill your stack if the caller happens to be
the wrong one, and just making it happen less often is not a fix - it
must not happen at all.