[issue1771] Restore hysteresis to vm_zeroidle

[Venkatesh Srinivas (via DragonFly issue tracker)]

Venkatesh Srinivas <me at acm.jhu.edu> added the comment:

As written I think the patch behaves like this:

if (zero_state == 0) /* We've not hit the upper limit */
   if (zeroed pages >= high count) /* hit the upper limit */
      zero_state = 1;
      return STOP_ZEROING_PAGES;
   return KEEP_ZEROING_PAGES;

if (zero_state == 1) /* We've hit the upper limit before */
   if (zeroed_pages >= LOW MARK) /* Still have free pages; also covers high */
      return STOP_ZEROING_PAGES;
   /* We've seen an upper limit; now we're below the lower limit. */
   /* Restore to 0 (not seen high limit) */
   zero_state = 0;
   return KEEP_ZEROING_PAGES;


What was wrong with this?

-- vs

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