x86, tlb: Switch cr3 in leave_mm() only when needed
authorSuresh Siddha <suresh.b.siddha@intel.com>
Fri, 23 Mar 2012 00:01:25 +0000 (17:01 -0700)
committerH. Peter Anvin <hpa@zytor.com>
Fri, 23 Mar 2012 00:23:48 +0000 (17:23 -0700)
commita6fca40f1d7f3e232c9de27c1cebbb9f787fbc4f
tree53206c42ab7bdc85e026d2023203209ef43e689d
parent722bc6b16771ed80871e1fd81c86d3627dda2ac8
x86, tlb: Switch cr3 in leave_mm() only when needed

Currently leave_mm() unconditionally switches the cr3 to swapper_pg_dir.
But there is no need to change the cr3, if we already left that mm.

intel_idle() for example calls leave_mm() on every deep c-state entry where
the CPU flushes the TLB for us. Similarly flush_tlb_all() was also calling
leave_mm() whenever the TLB is in LAZY state. Both these paths will be
improved with this change.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1332460885.16101.147.camel@sbsiddha-desk.sc.intel.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
arch/x86/mm/tlb.c