lkml.org 
[lkml]   [2020]   [Jun]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH for 5.8] mm: do_swap_page fix up the error code instantiation
I hope I haven't missed anything but the patch should be the following.

From acd488c22b4bb2ee42526be8ca67145d5127b014 Mon Sep 17 00:00:00 2001
From: Michal Hocko <mhocko@suse.com>
Date: Wed, 17 Jun 2020 10:40:47 +0200
Subject: [PATCH] mm: do_swap_page fix up the error code

do_swap_page returns error codes from the VM_FAULT* space. try_charge
might return -ENOMEM, though, and then do_swap_page simply returns 0
which means a success.

We almost never return ENOMEM for GFP_KERNEL single page charge. Except
for async OOM handling (oom_disabled v1). So this needs translation to
VM_FAULT_OOM otherwise the the page fault path will not notify the
userspace and wait for an action.

Fixes: 4c6355b25e8b ("mm: memcontrol: charge swapin pages on instantiation")
Signed-off-by: Michal Hocko <mhocko@suse.com>
---
mm/memory.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/memory.c b/mm/memory.c
index dc7f3543b1fd..d944b7946b27 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3140,8 +3140,10 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
err = mem_cgroup_charge(page, vma->vm_mm,
GFP_KERNEL);
ClearPageSwapCache(page);
- if (err)
+ if (err) {
+ err = VM_FAULT_OOM;
goto out_page;
+ }

lru_cache_add(page);
swap_readpage(page, true);
--
2.26.2
--
Michal Hocko
SUSE Labs

\
 
 \ /
  Last update: 2020-06-17 10:50    [W:0.070 / U:0.904 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site