On Thu 27-04-17 15:16:47, Igor Stoppa wrote:
> On 26/04/17 18:29, Igor Stoppa wrote:
>
> > On 26/04/17 17:47, Michal Hocko wrote:
>
> [...]
>
> >> Also the current mm tree has ___GFP_NOLOCKDEP which is not addressed
> >> here so I suspect you have based your change on the Linus tree.
>
> > I used your tree from kernel.org
>
> I found it, I was using master, instead of auto-latest (is it correct?)
yes
> But now I see something that I do not understand (apologies if I'm
> asking something obvious).
>
> First there is:
>
> [...]
> #define ___GFP_WRITE 0x800000u
> #define ___GFP_KSWAPD_RECLAIM 0x1000000u
> #ifdef CONFIG_LOCKDEP
> #define ___GFP_NOLOCKDEP 0x4000000u
> #else
> #define ___GFP_NOLOCKDEP 0
> #endif
>
> Then:
>
> /* Room for N __GFP_FOO bits */
> #define __GFP_BITS_SHIFT (25 + IS_ENABLED(CONFIG_LOCKDEP))
>
>
>
> Shouldn't it be either:
> ___GFP_NOLOCKDEP 0x2000000u
Yes it should. At the time when this patch was written this value was
used. Later I've removed __GFP_OTHER by 41b6167e8f74 ("mm: get rid of
__GFP_OTHER_NODE") and forgot to refresh this one. Thanks for noticing
this.
Andrew, could you fold the following in please?
---
>From 8dc9c917af215f659bb990fa48ae7b4753027c19 Mon Sep 17 00:00:00 2001
From: Michal Hocko <mhocko@xxxxxxxx>
Date: Thu, 27 Apr 2017 15:28:10 +0200
Subject: [PATCH] lockdep-allow-to-disable-reclaim-lockup-detection-fix
Igor Stoppa has noticed that __GFP_NOLOCKDEP can use a lower bit. At the
time lockdep-allow-to-disable-reclaim-lockup-detection was written we
still had __GFP_OTHER_NODE but I have removed it in 41b6167e8f74 ("mm:
get rid of __GFP_OTHER_NODE") and forgot to lower the bit value.
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
---
include/linux/gfp.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 2b1a44f5bdb6..a89d37e8b387 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -41,7 +41,7 @@ struct vm_area_struct;
#define ___GFP_WRITE 0x800000u
#define ___GFP_KSWAPD_RECLAIM 0x1000000u
#ifdef CONFIG_LOCKDEP
-#define ___GFP_NOLOCKDEP 0x4000000u
+#define ___GFP_NOLOCKDEP 0x2000000u
#else
#define ___GFP_NOLOCKDEP 0
#endif
--
2.11.0
--
Michal Hocko
SUSE Labs
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