From 75e1056f5c57050415b64cb761a3acc35d91f013 Mon Sep 17 00:00:00 2001 From: Venkatesh Pallipadi Date: Mon, 4 Oct 2010 17:03:16 -0700 Subject: sched: Fix softirq time accounting Peter Zijlstra found a bug in the way softirq time is accounted in VIRT_CPU_ACCOUNTING on this thread: http://lkml.indiana.edu/hypermail//linux/kernel/1009.2/01366.html The problem is, softirq processing uses local_bh_disable internally. There is no way, later in the flow, to differentiate between whether softirq is being processed or is it just that bh has been disabled. So, a hardirq when bh is disabled results in time being wrongly accounted as softirq. Looking at the code a bit more, the problem exists in !VIRT_CPU_ACCOUNTING as well. As account_system_time() in normal tick based accouting also uses softirq_count, which will be set even when not in softirq with bh disabled. Peter also suggested solution of using 2*SOFTIRQ_OFFSET as irq count for local_bh_{disable,enable} and using just SOFTIRQ_OFFSET while softirq processing. The patch below does that and adds API in_serving_softirq() which returns whether we are currently processing softirq or not. Also changes one of the usages of softirq_count in net/sched/cls_cgroup.c to in_serving_softirq. Looks like many usages of in_softirq really want in_serving_softirq. Those changes can be made individually on a case by case basis. Signed-off-by: Venkatesh Pallipadi Signed-off-by: Peter Zijlstra LKML-Reference: <1286237003-12406-2-git-send-email-venki@google.com> Signed-off-by: Ingo Molnar --- net/sched/cls_cgroup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/sched/cls_cgroup.c') diff --git a/net/sched/cls_cgroup.c b/net/sched/cls_cgroup.c index 78ef2c5e130b..37dff78e9cb1 100644 --- a/net/sched/cls_cgroup.c +++ b/net/sched/cls_cgroup.c @@ -123,7 +123,7 @@ static int cls_cgroup_classify(struct sk_buff *skb, struct tcf_proto *tp, * calls by looking at the number of nested bh disable calls because * softirqs always disables bh. */ - if (softirq_count() != SOFTIRQ_OFFSET) { + if (in_serving_softirq()) { /* If there is an sk_classid we'll use that. */ if (!skb->sk) return -1; -- cgit v1.2.2 From c00b2c9e79466d61979cd21af526cc6d5d0ee04f Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Wed, 3 Nov 2010 13:31:05 +0000 Subject: cls_cgroup: Fix crash on module unload Somewhere along the lines net_cls_subsys_id became a macro when cls_cgroup is built as a module. Not only did it make cls_cgroup completely useless, it also causes it to crash on module unload. This patch fixes this by removing that macro. Thanks to Eric Dumazet for diagnosing this problem. Reported-by: Randy Dunlap Signed-off-by: Herbert Xu Reviewed-by: Li Zefan Signed-off-by: David S. Miller --- net/sched/cls_cgroup.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'net/sched/cls_cgroup.c') diff --git a/net/sched/cls_cgroup.c b/net/sched/cls_cgroup.c index 37dff78e9cb1..d49c40fb7e09 100644 --- a/net/sched/cls_cgroup.c +++ b/net/sched/cls_cgroup.c @@ -34,8 +34,6 @@ struct cgroup_subsys net_cls_subsys = { .populate = cgrp_populate, #ifdef CONFIG_NET_CLS_CGROUP .subsys_id = net_cls_subsys_id, -#else -#define net_cls_subsys_id net_cls_subsys.subsys_id #endif .module = THIS_MODULE, }; -- cgit v1.2.2 From cc7ec456f82da7f89a5b376e613b3ac4311b3e9a Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 19 Jan 2011 19:26:56 +0000 Subject: net_sched: cleanups Cleanup net/sched code to current CodingStyle and practices. Reduce inline abuse Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/sched/cls_cgroup.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'net/sched/cls_cgroup.c') diff --git a/net/sched/cls_cgroup.c b/net/sched/cls_cgroup.c index d49c40fb7e09..32a335194ca5 100644 --- a/net/sched/cls_cgroup.c +++ b/net/sched/cls_cgroup.c @@ -56,7 +56,8 @@ static struct cgroup_subsys_state *cgrp_create(struct cgroup_subsys *ss, { struct cgroup_cls_state *cs; - if (!(cs = kzalloc(sizeof(*cs), GFP_KERNEL))) + cs = kzalloc(sizeof(*cs), GFP_KERNEL); + if (!cs) return ERR_PTR(-ENOMEM); if (cgrp->parent) @@ -94,8 +95,7 @@ static int cgrp_populate(struct cgroup_subsys *ss, struct cgroup *cgrp) return cgroup_add_files(cgrp, ss, ss_files, ARRAY_SIZE(ss_files)); } -struct cls_cgroup_head -{ +struct cls_cgroup_head { u32 handle; struct tcf_exts exts; struct tcf_ematch_tree ematches; @@ -166,7 +166,7 @@ static int cls_cgroup_change(struct tcf_proto *tp, unsigned long base, u32 handle, struct nlattr **tca, unsigned long *arg) { - struct nlattr *tb[TCA_CGROUP_MAX+1]; + struct nlattr *tb[TCA_CGROUP_MAX + 1]; struct cls_cgroup_head *head = tp->root; struct tcf_ematch_tree t; struct tcf_exts e; -- cgit v1.2.2