diff mbox series

[5/8] mmap_lock: change trace and locking order

Message ID 20210909011014.JJu-mAZB6%akpm@linux-foundation.org (mailing list archive)
State New
Headers show
Series [1/8] mm/hmm: bypass devmap pte when all pfn requested flags are fulfilled | expand

Commit Message

Andrew Morton Sept. 9, 2021, 1:10 a.m. UTC
From: Liam Howlett <liam.howlett@oracle.com>
Subject: mmap_lock: change trace and locking order

Print to the trace log before releasing the lock to avoid racing with
other trace log printers of the same lock type.

Link: https://lkml.kernel.org/r/20210903022041.1843024-1-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Suggested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michel Lespinasse <walken.cr@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/mmap_lock.h |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Comments

Liam R. Howlett Sept. 9, 2021, 12:56 p.m. UTC | #1
Andrew,

I sent a v3 of this patch with a better description as suggested by
Vlastimil Babka and Steven Rostedt.  I also forgot to add the
reviewed-by's and acked-by's from v2 as Steven Rostedt pointed out.
It's probably best to look at the email message [1].

1.
https://lore.kernel.org/linux-mm/20210907162537.27cbf082@gandalf.local.home/

Thanks,
Liam

* Andrew Morton <akpm@linux-foundation.org> [210908 21:10]:
> From: Liam Howlett <liam.howlett@oracle.com>
> Subject: mmap_lock: change trace and locking order
> 
> Print to the trace log before releasing the lock to avoid racing with
> other trace log printers of the same lock type.
> 
> Link: https://lkml.kernel.org/r/20210903022041.1843024-1-Liam.Howlett@oracle.com
> Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
> Suggested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Cc: Michel Lespinasse <walken.cr@gmail.com>
> Cc: Vlastimil Babka <vbabka@suse.cz>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
> 
>  include/linux/mmap_lock.h |    8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> --- a/include/linux/mmap_lock.h~mmap_lock-change-trace-and-locking-order
> +++ a/include/linux/mmap_lock.h
> @@ -101,14 +101,14 @@ static inline bool mmap_write_trylock(st
>  
>  static inline void mmap_write_unlock(struct mm_struct *mm)
>  {
> -	up_write(&mm->mmap_lock);
>  	__mmap_lock_trace_released(mm, true);
> +	up_write(&mm->mmap_lock);
>  }
>  
>  static inline void mmap_write_downgrade(struct mm_struct *mm)
>  {
> -	downgrade_write(&mm->mmap_lock);
>  	__mmap_lock_trace_acquire_returned(mm, false, true);
> +	downgrade_write(&mm->mmap_lock);
>  }
>  
>  static inline void mmap_read_lock(struct mm_struct *mm)
> @@ -140,8 +140,8 @@ static inline bool mmap_read_trylock(str
>  
>  static inline void mmap_read_unlock(struct mm_struct *mm)
>  {
> -	up_read(&mm->mmap_lock);
>  	__mmap_lock_trace_released(mm, false);
> +	up_read(&mm->mmap_lock);
>  }
>  
>  static inline bool mmap_read_trylock_non_owner(struct mm_struct *mm)
> @@ -155,8 +155,8 @@ static inline bool mmap_read_trylock_non
>  
>  static inline void mmap_read_unlock_non_owner(struct mm_struct *mm)
>  {
> -	up_read_non_owner(&mm->mmap_lock);
>  	__mmap_lock_trace_released(mm, false);
> +	up_read_non_owner(&mm->mmap_lock);
>  }
>  
>  static inline void mmap_assert_locked(struct mm_struct *mm)
> _
diff mbox series

Patch

--- a/include/linux/mmap_lock.h~mmap_lock-change-trace-and-locking-order
+++ a/include/linux/mmap_lock.h
@@ -101,14 +101,14 @@  static inline bool mmap_write_trylock(st
 
 static inline void mmap_write_unlock(struct mm_struct *mm)
 {
-	up_write(&mm->mmap_lock);
 	__mmap_lock_trace_released(mm, true);
+	up_write(&mm->mmap_lock);
 }
 
 static inline void mmap_write_downgrade(struct mm_struct *mm)
 {
-	downgrade_write(&mm->mmap_lock);
 	__mmap_lock_trace_acquire_returned(mm, false, true);
+	downgrade_write(&mm->mmap_lock);
 }
 
 static inline void mmap_read_lock(struct mm_struct *mm)
@@ -140,8 +140,8 @@  static inline bool mmap_read_trylock(str
 
 static inline void mmap_read_unlock(struct mm_struct *mm)
 {
-	up_read(&mm->mmap_lock);
 	__mmap_lock_trace_released(mm, false);
+	up_read(&mm->mmap_lock);
 }
 
 static inline bool mmap_read_trylock_non_owner(struct mm_struct *mm)
@@ -155,8 +155,8 @@  static inline bool mmap_read_trylock_non
 
 static inline void mmap_read_unlock_non_owner(struct mm_struct *mm)
 {
-	up_read_non_owner(&mm->mmap_lock);
 	__mmap_lock_trace_released(mm, false);
+	up_read_non_owner(&mm->mmap_lock);
 }
 
 static inline void mmap_assert_locked(struct mm_struct *mm)