On Sun, Dec 24, 2017 at 07:45:16PM +0000, Mark Johnston wrote: > Author: markj > Date: Sun Dec 24 19:45:16 2017 > New Revision: 327168 > URL: https://svnweb.freebsd.org/changeset/base/327168 > > Log: > Fix two problems with the page daemon control loop. > > Both issues caused the page daemon to erroneously go to sleep when > applications are consuming free pages at a high rate, leaving the > application threads blocked in VM_WAIT. > > 1) After completing an inactive queue scan, concurrent allocations may > have prevented the page daemon from meeting the v_free_min threshold. > In this case, the page daemon was going to sleep even when the > inactive queue contained plenty of clean pages. > 2) pagedaemon_wakeup() may be called without the free queues lock held. > This can lead to a lost wakeup if a call occurs after the page daemon > clears vm_pageout_wanted but before going to sleep. > > Fix 1) by ensuring that we start a new inactive queue scan immediately > if v_free_count < v_free_min after a prior scan. > > Fix 2) by adding a new subroutine, pagedaemon_wait(), called from > vm_wait() and vm_waitpfault(). It wakes up the page daemon if either > vm_pages_needed or vm_pageout_wanted is false, and atomically sleeps > on v_free_count. > > Reported by: jeff > Reviewed by: alc > MFC after: 2 weeks > Differential Revision: https://reviews.freebsd.org/D13424 > > Modified: > head/sys/vm/vm_page.c > head/sys/vm/vm_pageout.c > head/sys/vm/vm_pageout.h >
I now see threads blocked in VM_WAIT? https://people.freebsd.org/~pho/stress/log/mark013.txt - Peter _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
