* [PATCH bpf] bpf: use __GFP_COMP while allocating page
@ 2018-09-12 20:15 Tushar Dave
2018-09-12 21:49 ` Daniel Borkmann
0 siblings, 1 reply; 2+ messages in thread
From: Tushar Dave @ 2018-09-12 20:15 UTC (permalink / raw)
To: ast, daniel, davem, netdev, john.fastabend
Helper bpg_msg_pull_data() can allocate multiple pages while
linearizing multiple scatterlist elements into one shared page.
However, if the shared page has size > PAGE_SIZE, using
copy_page_to_iter() causes below warning.
e.g.
[ 6367.019832] WARNING: CPU: 2 PID: 7410 at lib/iov_iter.c:825
page_copy_sane.part.8+0x0/0x8
To avoid above warning, use __GFP_COMP while allocating multiple
contiguous pages.
Signed-off-by: Tushar Dave <tushar.n.dave@oracle.com>
---
net/core/filter.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/core/filter.c b/net/core/filter.c
index d301134..0b40f95 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2344,7 +2344,8 @@ struct sock *do_msg_redirect_map(struct sk_msg_buff *msg)
if (unlikely(bytes_sg_total > copy))
return -EINVAL;
- page = alloc_pages(__GFP_NOWARN | GFP_ATOMIC, get_order(copy));
+ page = alloc_pages(__GFP_NOWARN | GFP_ATOMIC | __GFP_COMP,
+ get_order(copy));
if (unlikely(!page))
return -ENOMEM;
p = page_address(page);
--
1.8.3.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH bpf] bpf: use __GFP_COMP while allocating page
2018-09-12 20:15 [PATCH bpf] bpf: use __GFP_COMP while allocating page Tushar Dave
@ 2018-09-12 21:49 ` Daniel Borkmann
0 siblings, 0 replies; 2+ messages in thread
From: Daniel Borkmann @ 2018-09-12 21:49 UTC (permalink / raw)
To: Tushar Dave, ast, davem, netdev, john.fastabend
On 09/12/2018 10:15 PM, Tushar Dave wrote:
> Helper bpg_msg_pull_data() can allocate multiple pages while
> linearizing multiple scatterlist elements into one shared page.
> However, if the shared page has size > PAGE_SIZE, using
> copy_page_to_iter() causes below warning.
>
> e.g.
> [ 6367.019832] WARNING: CPU: 2 PID: 7410 at lib/iov_iter.c:825
> page_copy_sane.part.8+0x0/0x8
>
> To avoid above warning, use __GFP_COMP while allocating multiple
> contiguous pages.
>
> Signed-off-by: Tushar Dave <tushar.n.dave@oracle.com>
Applied to bpf, thanks Tushar!
^ permalink raw reply [flat|nested] 2+ messages in thread
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