Date: Wed, 2 Sep 2009 17:33:51 +0000 (UTC) From: Attilio Rao <attilio@FreeBSD.org> To: cvs-src-old@freebsd.org Subject: cvs commit: src/sys/kern kern_lock.c kern_sx.c Message-ID: <200909021734.n82HY9MI016744@repoman.freebsd.org>
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attilio 2009-09-02 17:33:51 UTC
FreeBSD src repository
Modified files:
sys/kern kern_lock.c kern_sx.c
Log:
SVN rev 196772 on 2009-09-02 17:33:51Z by attilio
Fix some bugs related to adaptive spinning:
In the lockmgr support:
- GIANT_RESTORE() is just called when the sleep finishes, so the current
code can ends up into a giant unlock problem. Fix it by appropriately
call GIANT_RESTORE() when needed. Note that this is not exactly ideal
because for any interation of the adaptive spinning we drop and restore
Giant, but the overhead should be not a factor.
- In the lock held in exclusive mode case, after the adaptive spinning is
brought to completition, we should just retry to acquire the lock
instead to fallthrough. Fix that.
- Fix a style nit
In the sx support:
- Call GIANT_SAVE() before than looping. This saves some overhead because
in the current code GIANT_SAVE() is called several times.
Tested by: Giovanni Trematerra <giovanni dot trematerra at gmail dot com>
Revision Changes Path
1.146 +11 -2 src/sys/kern/kern_lock.c
1.70 +1 -1 src/sys/kern/kern_sx.c
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