From f29c9b1ccb52904ee442a933cf3dee628f9f4e62 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Thu, 6 Nov 2008 09:45:16 +0800 Subject: sched: fix a bug in sched domain degenerate Impact: re-add incorrectly eliminated sched domain layers (1) on i386 with SCHED_SMT and SCHED_MC enabled # mount -t cgroup -o cpuset xxx /mnt # echo 0 > /mnt/cpuset.sched_load_balance # mkdir /mnt/0 # echo 0 > /mnt/0/cpuset.cpus # dmesg CPU0 attaching sched-domain: domain 0: span 0 level CPU groups: 0 (2) on i386 with SCHED_MC enabled but SCHED_SMT disabled # same with (1) # dmesg CPU0 attaching NULL sched-domain. The bug is that some sched domains may be skipped unintentionally when degenerating (optimizing) sched domains. Signed-off-by: Li Zefan Acked-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index 82cc839c921..4c7e2bcdfa8 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6877,15 +6877,17 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) struct sched_domain *tmp; /* Remove the sched domains which do not contribute to scheduling. */ - for (tmp = sd; tmp; tmp = tmp->parent) { + for (tmp = sd; tmp; ) { struct sched_domain *parent = tmp->parent; if (!parent) break; + if (sd_parent_degenerate(tmp, parent)) { tmp->parent = parent->parent; if (parent->parent) parent->parent->child = tmp; - } + } else + tmp = tmp->parent; } if (sd && sd_degenerate(sd)) { -- cgit v1.2.3 From ca3273f9646694e0419cfb9d6c12deb1c9aff27c Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Fri, 7 Nov 2008 14:47:21 +0800 Subject: sched: fix memory leak in a failure path Impact: fix rare memory leak in the sched-domains manual reconfiguration code In the failure path, rd is not attached to a sched domain, so it causes a leak. Signed-off-by: Li Zefan Acked-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/sched.c b/kernel/sched.c index 4c7e2bcdfa8..57c933ffbee 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -7676,6 +7676,7 @@ static int __build_sched_domains(const cpumask_t *cpu_map, error: free_sched_groups(cpu_map, tmpmask); SCHED_CPUMASK_FREE((void *)allmasks); + kfree(rd); return -ENOMEM; #endif } -- cgit v1.2.3 From 14800984706bf6936bbec5187f736e928be5c218 Mon Sep 17 00:00:00 2001 From: Mike Galbraith Date: Fri, 7 Nov 2008 15:26:50 +0100 Subject: sched: fine-tune SD_MC_INIT Tune SD_MC_INIT the same way as SD_CPU_INIT: unset SD_BALANCE_NEWIDLE, and set SD_WAKE_BALANCE. This improves vmark by 5%: vmark 132102 125968 125497 messages/sec avg 127855.66 .984 vmark 139404 131719 131272 messages/sec avg 134131.66 1.033 Signed-off-by: Mike Galbraith Acked-by: Peter Zijlstra Signed-off-by: Ingo Molnar # *DOCUMENTATION* --- include/linux/topology.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/topology.h b/include/linux/topology.h index 34a7ee0ebed..a8d840595b7 100644 --- a/include/linux/topology.h +++ b/include/linux/topology.h @@ -120,10 +120,10 @@ void arch_update_cpu_topology(void); .wake_idx = 1, \ .forkexec_idx = 1, \ .flags = SD_LOAD_BALANCE \ - | SD_BALANCE_NEWIDLE \ | SD_BALANCE_FORK \ | SD_BALANCE_EXEC \ | SD_WAKE_AFFINE \ + | SD_WAKE_BALANCE \ | SD_SHARE_PKG_RESOURCES\ | BALANCE_FOR_MC_POWER, \ .last_balance = jiffies, \ -- cgit v1.2.3 From 52c642f33b14bfa1b00ef2b68296effb34a573f3 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Fri, 7 Nov 2008 16:09:23 +0100 Subject: sched: fine-tune SD_SIBLING_INIT fine-tune the HT sched-domains parameters as well. On a HT capable box, this increases lat_ctx performance from 23.87 usecs to 1.49 usecs: # before $ ./lat_ctx -s 0 2 "size=0k ovr=1.89 2 23.87 # after $ ./lat_ctx -s 0 2 "size=0k ovr=1.84 2 1.49 Signed-off-by: Ingo Molnar --- include/linux/topology.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/topology.h b/include/linux/topology.h index a8d840595b7..117f1b7405c 100644 --- a/include/linux/topology.h +++ b/include/linux/topology.h @@ -99,7 +99,7 @@ void arch_update_cpu_topology(void); | SD_BALANCE_FORK \ | SD_BALANCE_EXEC \ | SD_WAKE_AFFINE \ - | SD_WAKE_IDLE \ + | SD_WAKE_BALANCE \ | SD_SHARE_CPUPOWER, \ .last_balance = jiffies, \ .balance_interval = 1, \ -- cgit v1.2.3