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vm_pageout_scan_active: ensure ps_delta is initialized
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Authored by vangyzen on Aug 27 2020, 3:08 PM.

Details

Summary

Ensure ps_delta is initialized.

Reported by: Coverity

Diff Detail

Repository
rS FreeBSD src repository
Lint
Automatic diff as part of commit; lint not applicable.
Unit
Automatic diff as part of commit; unit tests not applicable.

Event Timeline

sys/vm/vm_pageout.c
1293 ↗(On Diff #76283)

I guess this is the only case where we can end up with a bogus ps_delta. It should be quite rare.

The assignment should go here, not at the top of the loop. We only break from the loop when the atomic_fcmpset at the end succeeds. In one iteration we might set ps_delta to a nonzero value, fail the update, and then exit the loop through this case, in which case ps_delta will be left equal to the old and now-incorrect value.

  • move init to the right place
vangyzen added inline comments.
sys/vm/vm_pageout.c
1293 ↗(On Diff #76283)

Indeed. Thank you.

This revision is now accepted and ready to land.Aug 27 2020, 4:34 PM
This revision was automatically updated to reflect the committed changes.
vangyzen marked an inline comment as done.