<div style="line-height:1.7;color:#000000;font-size:14px;font-family:Arial"><div style="margin: 0px;">I read the source code in kernel(kernel/sched.c):</div><div style="margin: 0px;"><img src="http://mail.126.com/js6/s?func=mbox:getMessageData&mid=208:1tbi0AF8U1pECuNk5wABsL&part=3" orgwidth="637" orgheight="442" data-image="1" style="border: 0px; width: 637px; height: 442px;"></div><div style="margin: 0px;"><br></div><div style="margin: 0px;">(include/asm-i386/system.h)</div><div style="margin: 0px;"><img src="http://mail.126.com/js6/s?func=mbox:getMessageData&mid=208:1tbi0AF8U1pECuNk5wABsL&part=4" orgwidth="592" orgheight="311" data-image="1" style="border: 0px; width: 592px; height: 311px;"></div><div style="margin: 0px;">My question is that: switch_to is defined as a macro, so I thoutht it will expand <b>"=a" (last) </b>as<b> </b><b>"=a" (prev)</b>, if that the <b>last</b> parameter is just for easy to read, is that right?</div></div><br><br><span title="neteasefooter"><p> </p></span>