CVS log for src/sys/uvm/uvm_init.c

Up to [cvs.NetBSD.org] / src / sys / uvm

Request diff between arbitrary revisions

Default branch: MAIN
Current tag: thorpej-cfargs2

Revision 1.55 / (download) - annotate - [select for diffs], Wed Nov 4 01:30:19 2020 UTC (3 years, 5 months ago) by chs
Branch: MAIN
CVS Tags: thorpej-i2c-spi-conf2-base, thorpej-i2c-spi-conf2, thorpej-i2c-spi-conf-base, thorpej-i2c-spi-conf, thorpej-futex2-base, thorpej-futex2, thorpej-futex-base, thorpej-cfargs2-base, thorpej-cfargs2, thorpej-cfargs-base, thorpej-cfargs, netbsd-10-base, netbsd-10-0-RELEASE, netbsd-10-0-RC6, netbsd-10-0-RC5, netbsd-10-0-RC4, netbsd-10-0-RC3, netbsd-10-0-RC2, netbsd-10-0-RC1, netbsd-10, cjep_sun2x-base1, cjep_sun2x-base, cjep_sun2x, cjep_staticlib_x-base1, cjep_staticlib_x-base, cjep_staticlib_x, bouyer-sunxi-drm-base, bouyer-sunxi-drm
Changes since 1.54: +5 -2 lines
Diff to previous 1.54 (colored)

In uvmpd_tryownerlock(), if the initial try-lock of the owner lock fails
then rather than do more try-locks and eventually sleep for a tick,
take a hold on the current owner's lock, drop the page interlock,
and acquire the lock that we took the hold on in a blocking fashion.
After we get the lock, check if the lock that we acquired is still
the lock for the owner of the page that we're interested in.
If the owner hasn't changed then can proceed with this page,
otherwise we will skip this page and move on to a different page.
This dramatically reduces the amount of time that the pagedaemon
sleeps trying to get locks, since even 1 tick is an eternity to sleep
in this context and it was easy to trigger that case in practice,
and with this new method the pagedaemon only very rarely actually blocks
to acquire the lock that it wants since the object locks are adaptive,
and when the pagedaemon does block then the amount of time it spends
sleeping will be generally be much less than 1 tick.

This form allows you to request diff's between any two revisions of a file. You may select a symbolic revision name using the selection box or you may type in a numeric name using the type-in text box.