x86: add clflush before monitor for Intel 7400 series
authorPallipadi, Venkatesh <venkatesh.pallipadi@intel.com>
Sat, 7 Feb 2009 00:52:05 +0000 (16:52 -0800)
committerIngo Molnar <mingo@elte.hu>
Mon, 9 Feb 2009 10:15:15 +0000 (11:15 +0100)
commite736ad548db152776de61d7a26805cfae77ce5ce
treebab2cb6560f2e038ccebf891cd847f37fd61a1b8
parent0cd5c3c80a0ebd68c08312fa7d8c13149cc61c4c
x86: add clflush before monitor for Intel 7400 series

For Intel 7400 series CPUs, the recommendation is to use a clflush on the
monitored address just before monitor and mwait pair [1].

This clflush makes sure that there are no false wakeups from mwait when the
monitored address was recently written to.

[1] "MONITOR/MWAIT Recommendations for Intel Xeon Processor 7400 series"
    section in specification update document of 7400 series
    http://download.intel.com/design/xeon/specupdt/32033601.pdf

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arch/x86/include/asm/cpufeature.h
arch/x86/kernel/cpu/intel.c
arch/x86/kernel/process.c