git: DragonFly_RELEASE_5_8 kernel - Fix excessive VM pageout flushes
dillon at crater.dragonflybsd.org
Thu Apr 23 19:03:55 PDT 2020
Author: Matthew Dillon <dillon at apollo.backplane.com>
Date: Wed Apr 22 19:39:37 2020 -0700
kernel - Fix excessive VM pageout flushes
* The VM pageout code was calculating the laundering limit improperly.
We were trying to calculate a per-pass limit within each queue list
but were not taking into account the fact that the number of queues
have greatly increased in the last few years AND also that the paging
scans only check 1/10 of each queue for each scan.
These fixes allow the pageout scan to pick-up many more clean pages
before beginning to stall-out on dirty pages.
* vm_max_launder is now calculated as 1/256 of physical memory at startup
instead of hardwired.
* local max_launder calculations now take into account the number of
queues and the fact that only 1/10 of each queue is checked in each
In addition, the local max_launder calculation is increased by the
pass number divided by 10 so as to only increase for each full queue
* the 'pass' variable passed down into helper functions is now divided
by 10 because we do not want it to 'increment' and trigger stronger
behavior until after the entire inactive queue has been scanned.
Summary of changes:
sys/vm/vm_pageout.c | 130 ++++++++++++++++++++++++++++++----------------------
1 file changed, 74 insertions(+), 56 deletions(-)
DragonFly BSD source repository
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