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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:02:38 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:02:38 +0000
commit08b74a000942a380fe028845f92cd3a0dee827d5 (patch)
treeaa78b4e12607c3e1fcce8d5cc42df4330792f118 /debian/patches-rt/0107-sched-Move-mmdrop-to-RCU-on-RT.patch
parentAdding upstream version 4.19.249. (diff)
downloadlinux-08b74a000942a380fe028845f92cd3a0dee827d5.tar.xz
linux-08b74a000942a380fe028845f92cd3a0dee827d5.zip
Adding debian version 4.19.249-2.debian/4.19.249-2debian
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'debian/patches-rt/0107-sched-Move-mmdrop-to-RCU-on-RT.patch')
-rw-r--r--debian/patches-rt/0107-sched-Move-mmdrop-to-RCU-on-RT.patch115
1 files changed, 115 insertions, 0 deletions
diff --git a/debian/patches-rt/0107-sched-Move-mmdrop-to-RCU-on-RT.patch b/debian/patches-rt/0107-sched-Move-mmdrop-to-RCU-on-RT.patch
new file mode 100644
index 000000000..9c6b2f686
--- /dev/null
+++ b/debian/patches-rt/0107-sched-Move-mmdrop-to-RCU-on-RT.patch
@@ -0,0 +1,115 @@
+From 977952ae9f00231e71587f8dc135949a2bed15e2 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Mon, 6 Jun 2011 12:20:33 +0200
+Subject: [PATCH 107/347] sched: Move mmdrop to RCU on RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz
+
+Takes sleeping locks and calls into the memory allocator, so nothing
+we want to do in task switch and oder atomic contexts.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ include/linux/mm_types.h | 4 ++++
+ include/linux/sched/mm.h | 11 +++++++++++
+ kernel/fork.c | 13 +++++++++++++
+ kernel/sched/core.c | 7 ++++++-
+ 4 files changed, 34 insertions(+), 1 deletion(-)
+
+diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
+index 3a9a996af229..202b736ccbfa 100644
+--- a/include/linux/mm_types.h
++++ b/include/linux/mm_types.h
+@@ -12,6 +12,7 @@
+ #include <linux/completion.h>
+ #include <linux/cpumask.h>
+ #include <linux/uprobes.h>
++#include <linux/rcupdate.h>
+ #include <linux/page-flags-layout.h>
+ #include <linux/workqueue.h>
+
+@@ -487,6 +488,9 @@ struct mm_struct {
+ bool tlb_flush_batched;
+ #endif
+ struct uprobes_state uprobes_state;
++#ifdef CONFIG_PREEMPT_RT_BASE
++ struct rcu_head delayed_drop;
++#endif
+ #ifdef CONFIG_HUGETLB_PAGE
+ atomic_long_t hugetlb_usage;
+ #endif
+diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
+index ef54f4b3f1e4..88e1a563f762 100644
+--- a/include/linux/sched/mm.h
++++ b/include/linux/sched/mm.h
+@@ -49,6 +49,17 @@ static inline void mmdrop(struct mm_struct *mm)
+ __mmdrop(mm);
+ }
+
++#ifdef CONFIG_PREEMPT_RT_BASE
++extern void __mmdrop_delayed(struct rcu_head *rhp);
++static inline void mmdrop_delayed(struct mm_struct *mm)
++{
++ if (atomic_dec_and_test(&mm->mm_count))
++ call_rcu(&mm->delayed_drop, __mmdrop_delayed);
++}
++#else
++# define mmdrop_delayed(mm) mmdrop(mm)
++#endif
++
+ void mmdrop(struct mm_struct *mm);
+
+ /*
+diff --git a/kernel/fork.c b/kernel/fork.c
+index f5a4c42233f0..114ff9724b02 100644
+--- a/kernel/fork.c
++++ b/kernel/fork.c
+@@ -642,6 +642,19 @@ void __mmdrop(struct mm_struct *mm)
+ }
+ EXPORT_SYMBOL_GPL(__mmdrop);
+
++#ifdef CONFIG_PREEMPT_RT_BASE
++/*
++ * RCU callback for delayed mm drop. Not strictly rcu, but we don't
++ * want another facility to make this work.
++ */
++void __mmdrop_delayed(struct rcu_head *rhp)
++{
++ struct mm_struct *mm = container_of(rhp, struct mm_struct, delayed_drop);
++
++ __mmdrop(mm);
++}
++#endif
++
+ static void mmdrop_async_fn(struct work_struct *work)
+ {
+ struct mm_struct *mm;
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index 4cc39856c4c6..676b9b213991 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -2734,9 +2734,13 @@ static struct rq *finish_task_switch(struct task_struct *prev)
+ * provided by mmdrop(),
+ * - a sync_core for SYNC_CORE.
+ */
++ /*
++ * We use mmdrop_delayed() here so we don't have to do the
++ * full __mmdrop() when we are the last user.
++ */
+ if (mm) {
+ membarrier_mm_sync_core_before_usermode(mm);
+- mmdrop(mm);
++ mmdrop_delayed(mm);
+ }
+ if (unlikely(prev_state == TASK_DEAD)) {
+ if (prev->sched_class->task_dead)
+@@ -5603,6 +5607,7 @@ void sched_setnuma(struct task_struct *p, int nid)
+ #endif /* CONFIG_NUMA_BALANCING */
+
+ #ifdef CONFIG_HOTPLUG_CPU
++
+ /*
+ * Ensure that the idle task is using init_mm right before its CPU goes
+ * offline.
+--
+2.36.1
+