The patch titled
Subject: task_stack: uninline stack_not_used
has been added to the -mm mm-unstable branch. Its filename is
task_stack-uninline-stack_not_used.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/task_stack-uninline-stack_not_used.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
Subject: task_stack: uninline stack_not_used
Date: Wed, 24 Jul 2024 20:33:22 +0000
Given that stack_not_used() is not performance critical function
uninline it.
Link: https://lkml.kernel.org/r/20240724203322.2765486-4-pasha.tatashin@xxxxxxxxxx
Signed-off-by: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
Acked-by: Shakeel Butt <shakeel.butt@xxxxxxxxx>
Cc: Domenico Cerasuolo <cerasuolodomenico@xxxxxxxxx>
Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Cc: Li Zhijian <lizhijian@xxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Nhat Pham <nphamcs@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/sched/task_stack.h | 18 +++---------------
kernel/exit.c | 19 +++++++++++++++++++
kernel/sched/core.c | 4 +---
3 files changed, 23 insertions(+), 18 deletions(-)
--- a/include/linux/sched/task_stack.h~task_stack-uninline-stack_not_used
+++ a/include/linux/sched/task_stack.h
@@ -95,23 +95,11 @@ static inline int object_is_on_stack(con
extern void thread_stack_cache_init(void);
#ifdef CONFIG_DEBUG_STACK_USAGE
+unsigned long stack_not_used(struct task_struct *p);
+#else
static inline unsigned long stack_not_used(struct task_struct *p)
{
- unsigned long *n = end_of_stack(p);
-
- do { /* Skip over canary */
-# ifdef CONFIG_STACK_GROWSUP
- n--;
-# else
- n++;
-# endif
- } while (!*n);
-
-# ifdef CONFIG_STACK_GROWSUP
- return (unsigned long)end_of_stack(p) - (unsigned long)n;
-# else
- return (unsigned long)n - (unsigned long)end_of_stack(p);
-# endif
+ return 0;
}
#endif
extern void set_task_stack_end_magic(struct task_struct *tsk);
--- a/kernel/exit.c~task_stack-uninline-stack_not_used
+++ a/kernel/exit.c
@@ -778,6 +778,25 @@ static void exit_notify(struct task_stru
}
#ifdef CONFIG_DEBUG_STACK_USAGE
+unsigned long stack_not_used(struct task_struct *p)
+{
+ unsigned long *n = end_of_stack(p);
+
+ do { /* Skip over canary */
+# ifdef CONFIG_STACK_GROWSUP
+ n--;
+# else
+ n++;
+# endif
+ } while (!*n);
+
+# ifdef CONFIG_STACK_GROWSUP
+ return (unsigned long)end_of_stack(p) - (unsigned long)n;
+# else
+ return (unsigned long)n - (unsigned long)end_of_stack(p);
+# endif
+}
+
/* Count the maximum pages reached in kernel stacks */
static inline void kstack_histogram(unsigned long used_stack)
{
--- a/kernel/sched/core.c~task_stack-uninline-stack_not_used
+++ a/kernel/sched/core.c
@@ -7405,7 +7405,7 @@ EXPORT_SYMBOL(io_schedule);
void sched_show_task(struct task_struct *p)
{
- unsigned long free = 0;
+ unsigned long free;
int ppid;
if (!try_get_task_stack(p))
@@ -7415,9 +7415,7 @@ void sched_show_task(struct task_struct
if (task_is_running(p))
pr_cont(" running task ");
-#ifdef CONFIG_DEBUG_STACK_USAGE
free = stack_not_used(p);
-#endif
ppid = 0;
rcu_read_lock();
if (pid_alive(p))
_
Patches currently in -mm which might be from pasha.tatashin@xxxxxxxxxx are
vmstat-kernel-stack-usage-histogram.patch
task_stack-uninline-stack_not_used.patch
