The patch titled
mm: make get_user_pages() interruptible
has been added to the -mm tree. Its filename is
mm-make-get_user_pages-interruptible.patch
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------------------------------------------------------
Subject: mm: make get_user_pages() interruptible
From: Ying Han <yinghan@xxxxxxxxxx>
The initial implementation of checking TIF_MEMDIE covers the cases of OOM
killing. If the process has been OOM killed, the TIF_MEMDIE is set and it
return immediately. This patch includes:
1. add the case that the SIGKILL is sent by user processes. The
process can try to get_user_pages() unlimited memory even if a user
process has sent a SIGKILL to it(maybe a monitor find the process
exceed its memory limit and try to kill it). In the old
implementation, the SIGKILL won't be handled until the get_user_pages()
returns.
2. change the return value to be ERESTARTSYS. It makes no sense to
return ENOMEM if the get_user_pages returned by getting a SIGKILL
signal. Considering the general convention for a system call
interrupted by a signal is ERESTARTNOSYS, so the current return value
is consistant to that.
Signed-off-by: Paul Menage <menage@xxxxxxxxxx>
Signed-off-by: Ying Han <yinghan@xxxxxxxxxx>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Reviewed-by: Pekka Enberg <penberg@xxxxxxxxxxxxxx>
Cc: Nick Piggin <nickpiggin@xxxxxxxxxxxx>
Cc: Hugh Dickins <hugh@xxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Lee Schermerhorn <lee.schermerhorn@xxxxxx>
Cc: Rohit Seth <rohitseth@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff -puN mm/memory.c~mm-make-get_user_pages-interruptible mm/memory.c
--- a/mm/memory.c~mm-make-get_user_pages-interruptible
+++ a/mm/memory.c
@@ -1275,12 +1275,11 @@ int __get_user_pages(struct task_struct
struct page *page;
/*
- * If tsk is ooming, cut off its access to large memory
- * allocations. It has a pending SIGKILL, but it can't
- * be processed until returning to user space.
+ * If we have a pending SIGKILL, don't keep
+ * allocating memory.
*/
- if (unlikely(test_tsk_thread_flag(tsk, TIF_MEMDIE)))
- return i ? i : -ENOMEM;
+ if (unlikely(fatal_signal_pending(current)))
+ return i ? i : -ERESTARTSYS;
if (write)
foll_flags |= FOLL_WRITE;
_
Patches currently in -mm which might be from yinghan@xxxxxxxxxx are
mm-make-get_user_pages-interruptible.patch
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