From: Sherry Yang <sherryy@xxxxxxxxxxx>
Subject: android: binder: drop lru lock in isolate callback
Drop the global lru lock in isolate callback before calling zap_page_range
which calls cond_resched, and re-acquire the global lru lock before
returning. Also change return code to LRU_REMOVED_RETRY.
Use mmput_async when fail to acquire mmap sem in an atomic context.
Fix "BUG: sleeping function called from invalid context"
errors when CONFIG_DEBUG_ATOMIC_SLEEP is enabled.
Also restore mmput_async, which was initially introduced in ec8d7c14e
("mm, oom_reaper: do not mmput synchronously from the oom reaper
context"), and was removed in 212925802 ("mm: oom: let oom_reap_task and
exit_mmap run concurrently").
Link: http://lkml.kernel.org/r/20170914182231.90908-1-sherryy@xxxxxxxxxxx
Fixes: f2517eb76f1f2 ("android: binder: Add global lru shrinker to binder")
Signed-off-by: Sherry Yang <sherryy@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Reported-by: Kyle Yan <kyan@xxxxxxxxxxxxxx>
Acked-by: Arve Hjønnevåg <arve@xxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Martijn Coenen <maco@xxxxxxxxxx>
Cc: Todd Kjos <tkjos@xxxxxxxxxx>
Cc: Riley Andrews <riandrews@xxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Hillf Danton <hdanton@xxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Hoeun Ryu <hoeun.ryu@xxxxxxxxx>
Cc: Christopher Lameter <cl@xxxxxxxxx>
Cc: Vegard Nossum <vegard.nossum@xxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/android/binder_alloc.c | 18 ++++++++++++------
include/linux/sched/mm.h | 6 ++++++
kernel/fork.c | 18 ++++++++++++++++++
3 files changed, 36 insertions(+), 6 deletions(-)
diff -puN drivers/android/binder_alloc.c~android-binder-drop-lru-lock-in-isolate-callback drivers/android/binder_alloc.c
--- a/drivers/android/binder_alloc.c~android-binder-drop-lru-lock-in-isolate-callback
+++ a/drivers/android/binder_alloc.c
@@ -913,6 +913,7 @@ enum lru_status binder_alloc_free_page(s
struct binder_alloc *alloc;
uintptr_t page_addr;
size_t index;
+ struct vm_area_struct *vma;
alloc = page->alloc;
if (!mutex_trylock(&alloc->mutex))
@@ -923,16 +924,22 @@ enum lru_status binder_alloc_free_page(s
index = page - alloc->pages;
page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
- if (alloc->vma) {
+ vma = alloc->vma;
+ if (vma) {
mm = get_task_mm(alloc->tsk);
if (!mm)
goto err_get_task_mm_failed;
if (!down_write_trylock(&mm->mmap_sem))
goto err_down_write_mmap_sem_failed;
+ }
+
+ list_lru_isolate(lru, item);
+ spin_unlock(lock);
+ if (vma) {
trace_binder_unmap_user_start(alloc, index);
- zap_page_range(alloc->vma,
+ zap_page_range(vma,
page_addr + alloc->user_buffer_offset,
PAGE_SIZE);
@@ -950,13 +957,12 @@ enum lru_status binder_alloc_free_page(s
trace_binder_unmap_kernel_end(alloc, index);
- list_lru_isolate(lru, item);
-
+ spin_lock(lock);
mutex_unlock(&alloc->mutex);
- return LRU_REMOVED;
+ return LRU_REMOVED_RETRY;
err_down_write_mmap_sem_failed:
- mmput(mm);
+ mmput_async(mm);
err_get_task_mm_failed:
err_page_already_freed:
mutex_unlock(&alloc->mutex);
diff -puN include/linux/sched/mm.h~android-binder-drop-lru-lock-in-isolate-callback include/linux/sched/mm.h
--- a/include/linux/sched/mm.h~android-binder-drop-lru-lock-in-isolate-callback
+++ a/include/linux/sched/mm.h
@@ -84,6 +84,12 @@ static inline bool mmget_not_zero(struct
/* mmput gets rid of the mappings and all user-space */
extern void mmput(struct mm_struct *);
+#ifdef CONFIG_MMU
+/* same as above but performs the slow path from the async context. Can
+ * be called from the atomic context as well
+ */
+void mmput_async(struct mm_struct *);
+#endif
/* Grab a reference to a task's mm, if it is not already going away */
extern struct mm_struct *get_task_mm(struct task_struct *task);
diff -puN kernel/fork.c~android-binder-drop-lru-lock-in-isolate-callback kernel/fork.c
--- a/kernel/fork.c~android-binder-drop-lru-lock-in-isolate-callback
+++ a/kernel/fork.c
@@ -946,6 +946,24 @@ void mmput(struct mm_struct *mm)
}
EXPORT_SYMBOL_GPL(mmput);
+#ifdef CONFIG_MMU
+static void mmput_async_fn(struct work_struct *work)
+{
+ struct mm_struct *mm = container_of(work, struct mm_struct,
+ async_put_work);
+
+ __mmput(mm);
+}
+
+void mmput_async(struct mm_struct *mm)
+{
+ if (atomic_dec_and_test(&mm->mm_users)) {
+ INIT_WORK(&mm->async_put_work, mmput_async_fn);
+ schedule_work(&mm->async_put_work);
+ }
+}
+#endif
+
/**
* set_mm_exe_file - change a reference to the mm's executable file
*
_
--
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