From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Chen, Kenneth W" Date: Wed, 07 Sep 2005 07:22:29 +0000 Subject: [patch] delete sync.i in ia64_switch_to() Message-Id: <200509070723.j877N9g25144@unix-os.sc.intel.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org The sync.i instruction in ia64_switch_to() context switch code looks like an old leftover code. sync.i instruction supposedly ensures flush cache operation issued by processor become visible to memory reference. Everywhere I looked where fc instruction is used (ia64_fc), a sync.i is always accompanied. Everywhere in the vicinity of context switch (save_switch_stack/load_switch_stack) don't have any fc instruction in there. I don't see any reason why we need to issue sync.i in context switch code. Patch to remove it. Signed-off-by: Ken Chen --- ./arch/ia64/kernel/entry.S.orig 2005-09-06 22:36:17.114182129 -0700 +++ ./arch/ia64/kernel/entry.S 2005-09-07 00:20:37.216644505 -0700 @@ -213,10 +213,6 @@ GLOBAL_ENTRY(ia64_switch_to) mov r13=in0 // set "current" pointer ;; DO_LOAD_SWITCH_STACK - -#ifdef CONFIG_SMP - sync.i // ensure "fc"s done by this CPU are visible on other CPUs -#endif br.ret.sptk.many rp // boogie on out in new context .map: