From: Jakub Kicinski <kuba@kernel.org>
To: David Howells <dhowells@redhat.com>
Cc: netdev@vger.kernel.org,
Alexander Duyck <alexander.duyck@gmail.com>,
"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>,
Jens Axboe <axboe@kernel.dk>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Menglong Dong <imagedong@tencent.com>
Subject: Re: [PATCH net-next v3 01/18] net: Copy slab data for sendmsg(MSG_SPLICE_PAGES)
Date: Thu, 22 Jun 2023 11:12:34 -0700 [thread overview]
Message-ID: <20230622111234.23aadd87@kernel.org> (raw)
In-Reply-To: <20230620145338.1300897-2-dhowells@redhat.com>
On Tue, 20 Jun 2023 15:53:20 +0100 David Howells wrote:
> If sendmsg() is passed MSG_SPLICE_PAGES and is given a buffer that contains
> some data that's resident in the slab, copy it rather than returning EIO.
How did that happen? I thought MSG_SPLICE_PAGES comes from former
sendpage users and sendpage can't operate on slab pages.
> This can be made use of by a number of drivers in the kernel, including:
> iwarp, ceph/rds, dlm, nvme, ocfs2, drdb. It could also be used by iscsi,
> rxrpc, sunrpc, cifs and probably others.
>
> skb_splice_from_iter() is given it's own fragment allocator as
> page_frag_alloc_align() can't be used because it does no locking to prevent
> parallel callers from racing.
The locking is to local_bh_disable(). Does the milliont^w new frag
allocator have any additional benefits?
> alloc_skb_frag() uses a separate folio for
> each cpu and locks to the cpu whilst allocating, reenabling cpu migration
> around folio allocation.
next prev parent reply other threads:[~2023-06-22 18:12 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-20 14:53 [PATCH net-next v3 00/18] splice, net: Switch over users of sendpage() and remove it David Howells
2023-06-20 14:53 ` [PATCH net-next v3 01/18] net: Copy slab data for sendmsg(MSG_SPLICE_PAGES) David Howells
2023-06-22 18:12 ` Jakub Kicinski [this message]
2023-06-22 18:28 ` Alexander Duyck
2023-06-22 19:40 ` David Howells
2023-06-22 20:28 ` Jakub Kicinski
2023-06-22 22:54 ` David Howells
2023-06-23 2:11 ` Jakub Kicinski
2023-06-23 9:08 ` David Howells
2023-06-23 9:52 ` Paolo Abeni
2023-06-23 10:06 ` David Howells
2023-06-23 10:21 ` Paolo Abeni
2023-06-23 8:08 ` Paolo Abeni
2023-06-23 9:06 ` David Howells
2023-06-23 9:37 ` Paolo Abeni
2023-06-23 10:00 ` David Howells
2023-06-20 14:53 ` [PATCH net-next v3 02/18] net: Display info about MSG_SPLICE_PAGES memory handling in proc David Howells
2023-06-23 8:18 ` Paolo Abeni
2023-06-23 9:42 ` David Howells
2023-06-20 14:53 ` [PATCH net-next v3 03/18] tcp_bpf, smc, tls, espintcp: Reduce MSG_SENDPAGE_NOTLAST usage David Howells
2023-06-20 14:53 ` [PATCH net-next v3 04/18] siw: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage to transmit David Howells
2023-06-21 8:57 ` Bernard Metzler
2023-06-20 14:53 ` [PATCH net-next v3 05/18] ceph: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage David Howells
2023-06-20 14:53 ` [PATCH net-next v3 06/18] net: Use sendmsg(MSG_SPLICE_PAGES) not sendpage in skb_send_sock() David Howells
2023-06-20 14:53 ` [PATCH net-next v3 07/18] ceph: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage() David Howells
2023-06-20 14:53 ` [PATCH net-next v3 08/18] rds: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage David Howells
2023-06-20 14:53 ` [PATCH net-next v3 09/18] dlm: " David Howells
2023-06-20 14:53 ` [PATCH net-next v3 10/18] nvme/host: Use sendmsg(MSG_SPLICE_PAGES) rather then sendpage David Howells
2023-06-21 10:15 ` Sagi Grimberg
2023-06-21 12:35 ` David Howells
2023-06-21 14:05 ` Sagi Grimberg
2023-06-29 14:45 ` Aurelien Aptel
2023-06-29 14:49 ` Sagi Grimberg
2023-06-29 15:02 ` Aurelien Aptel
2023-06-29 21:23 ` David Howells
2023-06-29 21:33 ` Sagi Grimberg
2023-06-29 21:34 ` David Howells
2023-06-29 23:43 ` Jakub Kicinski
2023-06-30 16:10 ` Nathan Chancellor
2023-06-30 16:14 ` Jakub Kicinski
2023-06-30 19:28 ` Nathan Chancellor
2023-07-07 20:45 ` Nick Desaulniers
2023-06-20 14:53 ` [PATCH net-next v3 11/18] nvme/target: " David Howells
2023-06-20 14:53 ` [PATCH net-next v3 12/18] smc: Drop smc_sendpage() in favour of smc_sendmsg() + MSG_SPLICE_PAGES David Howells
2023-06-20 14:53 ` [PATCH net-next v3 13/18] ocfs2: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage() David Howells
2023-06-20 14:53 ` [PATCH net-next v3 14/18] drbd: " David Howells
2023-06-20 14:53 ` [PATCH net-next v3 15/18] drdb: Send an entire bio in a single sendmsg David Howells
2023-06-20 14:53 ` [PATCH net-next v3 16/18] iscsi: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage David Howells
2023-06-20 14:53 ` [PATCH net-next v3 18/18] net: Kill MSG_SENDPAGE_NOTLAST David Howells
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