On Thu 31-05-18 11:10:22, Michal Hocko wrote:
> On Thu 31-05-18 10:55:32, Michal Hocko wrote:
> > On Thu 31-05-18 04:35:31, Eric Dumazet wrote:
> [...]
> > > I merely copied/pasted from alloc_skb_with_frags() :/
> >
> > I will have a look at it. Thanks!
>
> OK, so this is an example of an incremental development ;).
>
> __GFP_NORETRY was added by ed98df3361f0 ("net: use __GFP_NORETRY for
> high order allocations") to prevent from OOM killer. Yet this was
> not enough because fb05e7a89f50 ("net: don't wait for order-3 page
> allocation") didn't want an excessive reclaim for non-costly orders
> so it made it completely NOWAIT while it preserved __GFP_NORETRY in
> place which is now redundant. Should I send a patch?
Just in case you are interested
---
>From 5010543ed6f73e4c00367801486dca8d5c63b2ce Mon Sep 17 00:00:00 2001
From: Michal Hocko <mhocko@xxxxxxxx>
Date: Mon, 4 Jun 2018 15:07:37 +0200
Subject: [PATCH] net: cleanup gfp mask in alloc_skb_with_frags
alloc_skb_with_frags uses __GFP_NORETRY for non-sleeping allocations
which is just a noop and a little bit confusing.
__GFP_NORETRY was added by ed98df3361f0 ("net: use __GFP_NORETRY for
high order allocations") to prevent from the OOM killer. Yet this was
not enough because fb05e7a89f50 ("net: don't wait for order-3 page
allocation") didn't want an excessive reclaim for non-costly orders
so it made it completely NOWAIT while it preserved __GFP_NORETRY in
place which is now redundant.
Drop the pointless __GFP_NORETRY because this function is used as
copy&paste source for other places.
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
---
net/core/skbuff.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 857e4e6f751a..c1f22adc30de 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5239,8 +5239,7 @@ struct sk_buff *alloc_skb_with_frags(unsigned long header_len,
if (npages >= 1 << order) {
page = alloc_pages((gfp_mask & ~__GFP_DIRECT_RECLAIM) |
__GFP_COMP |
- __GFP_NOWARN |
- __GFP_NORETRY,
+ __GFP_NOWARN,
order);
if (page)
goto fill_page;
--
2.17.0
--
Michal Hocko
SUSE Labs
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