• Stephane Eranian's avatar
    [PATCH] x86-64 TIF flags for debug regs and io bitmap in ctxsw · d3a4f48d
    Stephane Eranian authored
    Hello,
    
    Following my discussion with Andi. Here is a patch that introduces
    two new TIF flags to simplify the context switch code in __switch_to().
    The idea is to minimize the number of cache lines accessed in the common
    case, i.e., when neither the debug registers nor the I/O bitmap are used.
    
    This patch covers the x86-64 modifications. A patch for i386 follows.
    
    Changelog:
    	- add TIF_DEBUG to track when debug registers are active
    	- add TIF_IO_BITMAP to track when I/O bitmap is used
    	- modify __switch_to() to use the new TIF flags
    
    <signed-off-by>: eranian@hpl.hp.com
    Signed-off-by: default avatarAndi Kleen <ak@suse.de>
    d3a4f48d
process.c 19.9 KB