From: Ashok Raj Date: Fri, 9 Sep 2005 20:01:52 +0000 (-0700) Subject: [PATCH] x86_64: Don't do broadcast IPIs when hotplug is enabled in flat mode. X-Git-Tag: v2.6.14-rc1~461 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fdf26d933a8171c2a5bd35b4a5ca3b099a216a35;p=linux-2.6 [PATCH] x86_64: Don't do broadcast IPIs when hotplug is enabled in flat mode. The use of non-shortcut version of routines breaking CPU hotplug. The option to select this via cmdline also is deleted with the physflat patch, hence directly placing this code under CONFIG_HOTPLUG_CPU. We dont want to use broadcast mode IPI's when hotplug is enabled. This causes bad effects in send IPI to a cpu that is offline which can trip when the cpu is in the process of being kicked alive. Signed-off-by: Ashok Raj Acked-by: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/arch/x86_64/kernel/genapic_flat.c b/arch/x86_64/kernel/genapic_flat.c index adc96282a9..6d57da96bf 100644 --- a/arch/x86_64/kernel/genapic_flat.c +++ b/arch/x86_64/kernel/genapic_flat.c @@ -78,8 +78,18 @@ static void flat_send_IPI_mask(cpumask_t cpumask, int vector) static void flat_send_IPI_allbutself(int vector) { +#ifndef CONFIG_HOTPLUG_CPU if (((num_online_cpus()) - 1) >= 1) __send_IPI_shortcut(APIC_DEST_ALLBUT, vector,APIC_DEST_LOGICAL); +#else + cpumask_t allbutme = cpu_online_map; + int me = get_cpu(); /* Ensure we are not preempted when we clear */ + cpu_clear(me, allbutme); + + if (!cpus_empty(allbutme)) + flat_send_IPI_mask(allbutme, vector); + put_cpu(); +#endif } static void flat_send_IPI_all(int vector)