Re: [PATCH net-next v10 08/16] tls: Inline do_tcp_sendpages()

From: Tariq Toukan <ttoukan.linux@gmail.com>
To: Jakub Kicinski <kuba@kernel.org>
Cc: David Howells <dhowells@redhat.com>,
	netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Paolo Abeni <pabeni@redhat.com>,
	Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
	David Ahern <dsahern@kernel.org>,
	Matthew Wilcox <willy@infradead.org>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Christoph Hellwig <hch@infradead.org>,
	Jens Axboe <axboe@kernel.dk>, Jeff Layton <jlayton@kernel.org>,
	Christian Brauner <brauner@kernel.org>,
	Chuck Lever III <chuck.lever@oracle.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, Boris Pismenny <borisp@nvidia.com>,
	John Fastabend <john.fastabend@gmail.com>,
	Gal Pressman <gal@nvidia.com>,
	ranro@nvidia.com, samiram@nvidia.com, drort@nvidia.com,
	Tariq Toukan <tariqt@nvidia.com>
Subject: Re: [PATCH net-next v10 08/16] tls: Inline do_tcp_sendpages()
Date: Wed, 26 Jul 2023 22:20:42 +0300	[thread overview]
Message-ID: <e9c41176-829a-af5a-65d2-78a2f414cd04@gmail.com> (raw)
In-Reply-To: <20230725173036.442ba8ba@kernel.org>

On 26/07/2023 3:30, Jakub Kicinski wrote:
> On Sun, 23 Jul 2023 09:35:56 +0300 Tariq Toukan wrote:
>> Hi Jakub, David,
>>
>> We repro the issue on the server side using this client command:
>> $ wrk -b2.2.2.2 -t4 -c1000 -d5 --timeout 5s
>> https://2.2.2.3:20443/256000b.img
>>
>> Port 20443 is configured with:
>>       ssl_ciphers ECDHE-RSA-AES128-GCM-SHA256;
>>       sendfile    off;
>>
>>
>> Important:
>> 1. Couldn't repro with files smaller than 40KB.
>> 2. Couldn't repro with "sendfile    on;"
>>
>> In addition, we collected the vmcore (forced by panic_on_warn), it can
>> be downloaded from here:
>> https://drive.google.com/file/d/1Fi2dzgq6k2hb2L_kwyntRjfLF6_RmbxB/view?usp=sharing
> 
> This has no symbols :(
> 

Uh.. :/
I'll try to fix this and re-generate.

> There is a small bug in this commit, we should always set SPLICE.
> But I don't see how that'd cause the warning you're seeing.
> Does your build have CONFIG_DEBUG_VM enabled?

No.

# CONFIG_DEBUG_VM is not set
# CONFIG_DEBUG_VM_PGTABLE is not set

> 
> -->8-------------------------
> 
> From: Jakub Kicinski <kuba@kernel.org>
> Date: Tue, 25 Jul 2023 17:03:25 -0700
> Subject: net: tls: set MSG_SPLICE_PAGES consistently
> 
> We used to change the flags for the last segment, because
> non-last segments had the MSG_SENDPAGE_NOTLAST flag set.
> That flag is no longer a thing so remove the setting.
> 
> Since flags most likely don't have MSG_SPLICE_PAGES set
> this avoids passing parts of the sg as splice and parts
> as non-splice.
> 
> ... tags ...
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---
>   net/tls/tls_main.c | 3 ---
>   1 file changed, 3 deletions(-)
> 
> diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c
> index b6896126bb92..4a8ee2f6badb 100644
> --- a/net/tls/tls_main.c
> +++ b/net/tls/tls_main.c
> @@ -139,9 +139,6 @@ int tls_push_sg(struct sock *sk,
>   
>   	ctx->splicing_pages = true;
>   	while (1) {
> -		if (sg_is_last(sg))
> -			msg.msg_flags = flags;
> -
>   		/* is sending application-limited? */
>   		tcp_rate_check_app_limited(sk);
>   		p = sg_page(sg);

I'll test this anyway tomorrow and update.

Regards,
Tariq