From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: + psi-move-pf_memstall-out-of-task-flags.patch added to -mm tree Date: Wed, 18 Mar 2020 14:03:59 -0700 Message-ID: <20200318210359.4Bxem2mDA%akpm@linux-foundation.org> References: <20200305222751.6d781a3f2802d79510941e4e@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from mail.kernel.org ([198.145.29.99]:39390 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727673AbgCRVEB (ORCPT ); Wed, 18 Mar 2020 17:04:01 -0400 In-Reply-To: <20200305222751.6d781a3f2802d79510941e4e@linux-foundation.org> Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: hannes@cmpxchg.org, laoar.shao@gmail.com, mm-commits@vger.kernel.org, willy@infradead.org The patch titled Subject: psi: move PF_MEMSTALL out of task->flags has been added to the -mm tree. Its filename is psi-move-pf_memstall-out-of-task-flags.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/psi-move-pf_memstall-out-of-task-flags.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/psi-move-pf_memstall-out-of-task-flags.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Yafang Shao Subject: psi: move PF_MEMSTALL out of task->flags The task->flags is a 32-bits flag, in which 31 bits have already been consumed. So it is hard to introduce other new per process flag. Currently there're still enough spaces in the bit-field section of task_struct, so we can define the memstall state as a single bit in task_struct instead. This patch also removes an out-of-date comment pointed out by Matthew. Link: http://lkml.kernel.org/r/1584408485-1921-1-git-send-email-laoar.shao@gmail.com Signed-off-by: Yafang Shao Suggested-by: Johannes Weiner Acked-by: Johannes Weiner Cc: Matthew Wilcox Signed-off-by: Andrew Morton --- include/linux/sched.h | 6 ++++-- kernel/sched/psi.c | 12 ++++++------ kernel/sched/stats.h | 10 +++++----- 3 files changed, 15 insertions(+), 13 deletions(-) --- a/include/linux/sched.h~psi-move-pf_memstall-out-of-task-flags +++ a/include/linux/sched.h @@ -782,9 +782,12 @@ struct task_struct { unsigned frozen:1; #endif #ifdef CONFIG_BLK_CGROUP - /* to be used once the psi infrastructure lands upstream. */ unsigned use_memdelay:1; #endif +#ifdef CONFIG_PSI + /* Stalled due to lack of memory */ + unsigned in_memstall:1; +#endif unsigned long atomic_flags; /* Flags requiring atomic access. */ @@ -1477,7 +1480,6 @@ extern struct pid *cad_pid; #define PF_KTHREAD 0x00200000 /* I am a kernel thread */ #define PF_RANDOMIZE 0x00400000 /* Randomize virtual address space */ #define PF_SWAPWRITE 0x00800000 /* Allowed to write to swap */ -#define PF_MEMSTALL 0x01000000 /* Stalled due to lack of memory */ #define PF_UMH 0x02000000 /* I'm an Usermodehelper process */ #define PF_NO_SETAFFINITY 0x04000000 /* Userland is not allowed to meddle with cpus_mask */ #define PF_MCE_EARLY 0x08000000 /* Early kill for mce process policy */ --- a/kernel/sched/psi.c~psi-move-pf_memstall-out-of-task-flags +++ a/kernel/sched/psi.c @@ -818,17 +818,17 @@ void psi_memstall_enter(unsigned long *f if (static_branch_likely(&psi_disabled)) return; - *flags = current->flags & PF_MEMSTALL; + *flags = current->in_memstall; if (*flags) return; /* - * PF_MEMSTALL setting & accounting needs to be atomic wrt + * in_memstall setting & accounting needs to be atomic wrt * changes to the task's scheduling state, otherwise we can * race with CPU migration. */ rq = this_rq_lock_irq(&rf); - current->flags |= PF_MEMSTALL; + current->in_memstall = 1; psi_task_change(current, 0, TSK_MEMSTALL); rq_unlock_irq(rq, &rf); @@ -851,13 +851,13 @@ void psi_memstall_leave(unsigned long *f if (*flags) return; /* - * PF_MEMSTALL clearing & accounting needs to be atomic wrt + * in_memstall clearing & accounting needs to be atomic wrt * changes to the task's scheduling state, otherwise we could * race with CPU migration. */ rq = this_rq_lock_irq(&rf); - current->flags &= ~PF_MEMSTALL; + current->in_memstall = 0; psi_task_change(current, TSK_MEMSTALL, 0); rq_unlock_irq(rq, &rf); @@ -921,7 +921,7 @@ void cgroup_move_task(struct task_struct else if (task->in_iowait) task_flags = TSK_IOWAIT; - if (task->flags & PF_MEMSTALL) + if (task->in_memstall) task_flags |= TSK_MEMSTALL; if (task_flags) --- a/kernel/sched/stats.h~psi-move-pf_memstall-out-of-task-flags +++ a/kernel/sched/stats.h @@ -70,7 +70,7 @@ static inline void psi_enqueue(struct ta return; if (!wakeup || p->sched_psi_wake_requeue) { - if (p->flags & PF_MEMSTALL) + if (p->in_memstall) set |= TSK_MEMSTALL; if (p->sched_psi_wake_requeue) p->sched_psi_wake_requeue = 0; @@ -90,7 +90,7 @@ static inline void psi_dequeue(struct ta return; if (!sleep) { - if (p->flags & PF_MEMSTALL) + if (p->in_memstall) clear |= TSK_MEMSTALL; } else { if (p->in_iowait) @@ -109,14 +109,14 @@ static inline void psi_ttwu_dequeue(stru * deregister its sleep-persistent psi states from the old * queue, and let psi_enqueue() know it has to requeue. */ - if (unlikely(p->in_iowait || (p->flags & PF_MEMSTALL))) { + if (unlikely(p->in_iowait || p->in_memstall)) { struct rq_flags rf; struct rq *rq; int clear = 0; if (p->in_iowait) clear |= TSK_IOWAIT; - if (p->flags & PF_MEMSTALL) + if (p->in_memstall) clear |= TSK_MEMSTALL; rq = __task_rq_lock(p, &rf); @@ -131,7 +131,7 @@ static inline void psi_task_tick(struct if (static_branch_likely(&psi_disabled)) return; - if (unlikely(rq->curr->flags & PF_MEMSTALL)) + if (unlikely(rq->curr->in_memstall)) psi_memstall_tick(rq->curr, cpu_of(rq)); } #else /* CONFIG_PSI */ _ Patches currently in -mm which might be from laoar.shao@gmail.com are mm-memcg-fix-build-error-around-the-usage-of-kmem_caches.patch psi-move-pf_memstall-out-of-task-flags.patch