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From:   Eric Dumazet <edumazet@google.com>
Date:   Thu, 6 Apr 2023 11:46:42 +0200
Message-ID: <CANn89iLFc3gxo-5gEn36VFYdocXQPiAqRsTPEHcB8JA3mw8+8g@mail.gmail.com>
Subject: Re: [PATCH net-next v5 00/19] splice, net: Replace sendpage with
 sendmsg(MSG_SPLICE_PAGES), part 1
To:     David Howells <dhowells@redhat.com>
Cc:     netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
        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
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On Thu, Apr 6, 2023 at 11:42=E2=80=AFAM David Howells <dhowells@redhat.com>=
 wrote:
>
> Here's the first tranche of patches towards providing a MSG_SPLICE_PAGES
> internal sendmsg flag that is intended to replace the ->sendpage() op wit=
h
> calls to sendmsg().  MSG_SPLICE is a hint that tells the protocol that it
> should splice the pages supplied if it can and copy them if not.
>

I find this patch series quite big/risky for 6.4

Can you spell out why we need "unspliceable pages support" ?
This seems to add quite a lot of code in fast paths.
Thanks.