From 8f0aae7bd8f9c2ad50d680e4ee94e4103e1b3a1a Mon Sep 17 00:00:00 2001 From: Johannes Weiner Date: Tue, 31 May 2022 23:19:54 +0800 Subject: [PATCH] psi: Pressure states are unlikely mainline inclusion from mainline-v5.13-rc1 commit fddc8bab531e217806b84906681324377d741c6c category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I562O9 CVE: NA backport: openEuler-22.03-LTS Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=fddc8bab531e217806b84906681324377d741c6c -------------------------------- Move the unlikely branches out of line. This eliminates undesirable jumps during wakeup and sleeps for workloads that aren't under any sort of resource pressure. Signed-off-by: Johannes Weiner Signed-off-by: Chengming Zhou Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Link: https://lkml.kernel.org/r/20210303034659.91735-4-zhouchengming@bytedance.com Signed-off-by: Chen Wandun Reviewed-by: Kefeng Wang Signed-off-by: Zheng Zengkai --- kernel/sched/psi.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index f27518bdc6c9..51566f01cd4a 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -226,17 +226,17 @@ static bool test_state(unsigned int *tasks, enum psi_states state) { switch (state) { case PSI_IO_SOME: - return tasks[NR_IOWAIT]; + return unlikely(tasks[NR_IOWAIT]); case PSI_IO_FULL: - return tasks[NR_IOWAIT] && !tasks[NR_RUNNING]; + return unlikely(tasks[NR_IOWAIT] && !tasks[NR_RUNNING]); case PSI_MEM_SOME: - return tasks[NR_MEMSTALL]; + return unlikely(tasks[NR_MEMSTALL]); case PSI_MEM_FULL: - return tasks[NR_MEMSTALL] && !tasks[NR_RUNNING]; + return unlikely(tasks[NR_MEMSTALL] && !tasks[NR_RUNNING]); case PSI_CPU_SOME: - return tasks[NR_RUNNING] > tasks[NR_ONCPU]; + return unlikely(tasks[NR_RUNNING] > tasks[NR_ONCPU]); case PSI_CPU_FULL: - return tasks[NR_RUNNING] && !tasks[NR_ONCPU]; + return unlikely(tasks[NR_RUNNING] && !tasks[NR_ONCPU]); case PSI_NONIDLE: return tasks[NR_IOWAIT] || tasks[NR_MEMSTALL] || tasks[NR_RUNNING]; @@ -737,7 +737,7 @@ static void psi_group_change(struct psi_group *group, int cpu, * task in a cgroup is in_memstall, the corresponding groupc * on that cpu is in PSI_MEM_FULL state. */ - if (groupc->tasks[NR_ONCPU] && cpu_curr(cpu)->in_memstall) + if (unlikely(groupc->tasks[NR_ONCPU] && cpu_curr(cpu)->in_memstall)) state_mask |= (1 << PSI_MEM_FULL); groupc->state_mask = state_mask; -- GitLab