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
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------------------------------------------------------
From: Yafang Shao <laoar.shao@xxxxxxxxx>
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This patch also removes an out-of-date comment pointed out by Matthew.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@xxxxxxxxx
Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
Suggested-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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@xxxxxxxxx are
mm-memcg-fix-build-error-around-the-usage-of-kmem_caches.patch
psi-move-pf_memstall-out-of-task-flags.patch
