Ugly workaround in nmbclust_update(). Additionally to setting the limit also modify the hiwat mark. This was done in pool_sethardlimit() until rev. 1.99. Without this the mbuf cluster pool may return free pages too quickly with the result that m_clget() may fail while populating DMA rings. Seems to fix some hangs seen on MCLGETI() interfaces on i386 e.g. PR 6524. A proper fix is to make all drivers handle empty rings but that will take a while to implement.  With and OK mikeb@
Ugly workaround in nmbclust_update(). Additionally to setting the limit
also modify the hiwat mark. This was done in pool_sethardlimit() until
rev. 1.99. Without this the mbuf cluster pool may return free pages too
quickly with the result that m_clget() may fail while populating DMA rings.
Seems to fix some hangs seen on MCLGETI() interfaces on i386 e.g. PR 6524.
A proper fix is to make all drivers handle empty rings but that will take
a while to implement.  With and OK mikeb@

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars