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Default branch: MAIN
Current tag: yamt-kmem-base3
Revision 1.10 / (download) - annotate - [select for diffs], Fri Mar 9 19:21:59 2007 UTC (17 years, 1 month ago) by thorpej
Branch: MAIN
CVS Tags: yamt-x86pmap-base4,
yamt-x86pmap-base3,
yamt-x86pmap-base2,
yamt-x86pmap-base,
yamt-x86pmap,
yamt-kmem-base3,
yamt-kmem-base2,
yamt-kmem-base,
yamt-kmem,
yamt-idlelwp-base8,
vmlocking2-base3,
vmlocking2-base2,
vmlocking2-base1,
vmlocking2,
vmlocking-nbase,
vmlocking-base,
vmlocking,
thorpej-atomic-base,
reinoud-bufcleanup-nbase,
reinoud-bufcleanup-base,
reinoud-bufcleanup,
ppcoea-renovation-base,
ppcoea-renovation,
nick-csl-alignment-base5,
nick-csl-alignment-base,
nick-csl-alignment,
mjf-ufs-trans-base,
mjf-ufs-trans,
matt-mips64-base,
matt-mips64,
jmcneill-pm-base,
jmcneill-pm,
jmcneill-base,
cube-autoconf-base,
cube-autoconf,
chris-arm-intr-rework-base3,
chris-arm-intr-rework-base2,
chris-arm-intr-rework-base,
bouyer-xenamd64-base2,
bouyer-xenamd64-base,
bouyer-xenamd64
Branch point for: thorpej-atomic,
mjf-devfs,
matt-armv6,
hpcarm-cleanup,
chris-arm-intr-rework,
bouyer-xeni386
Changes since 1.9: +5 -1
lines
Diff to previous 1.9 (colored)
Rewrite the ARM mutex implementation to be of the simple-mutex variety. Because pre-v6 ARM lacks support for an atomic compare-and-swap, we implement _lock_cas() as a restartable atomic squence that is checked in the IRQ handler right before AST processing. (This is safe because, for all practical purposes, there are no SMP pre-v6 ARM systems.) This can serve as a model for other non-MP platforms that lack the necessary atomic operations for mutexes (SuperH, for example). Upshots of this change: - kmutex_t is now down to 8 bytes on ARM; about as good as we can get. - ARM2 systems don't have to trap and emulate SWP or SWPB for mutexes. The acorn26 port is not updated by this commit to do the LOCK_CAS_CHECK. That is left as an exercise for the port maintainer. Reviewed and tested by Matt Thomas.