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[34.150.157.240]) by smtp.gmail.com with ESMTPSA id z6-20020a0cfec6000000b005dd8b9345a0sm5617916qvs.56.2023.03.30.10.51.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Mar 2023 10:51:57 -0700 (PDT) Date: Thu, 30 Mar 2023 13:51:56 -0400 From: Willem de Bruijn To: David Howells , Willem de Bruijn Cc: dhowells@redhat.com, Matthew Wilcox , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Al Viro , Christoph Hellwig , Jens Axboe , Jeff Layton , Christian Brauner , Chuck Lever III , Linus Torvalds , netdev@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Message-ID: <6425cc3c9d750_21f56920832@willemb.c.googlers.com.notmuch> In-Reply-To: <854582.1680188845@warthog.procyon.org.uk> References: <64259c7b2b327_21883920818@willemb.c.googlers.com.notmuch> <20230329141354.516864-1-dhowells@redhat.com> <20230329141354.516864-5-dhowells@redhat.com> <854582.1680188845@warthog.procyon.org.uk> Subject: Re: [RFC PATCH v2 04/48] net: Declare MSG_SPLICE_PAGES internal sendmsg() flag Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 990A7C001F X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: jf1mt7zyhu3k8aeafwmbngbrayd7tmfr X-HE-Tag: 1680198723-988352 X-HE-Meta: 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 ePmO3Dtf 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: David Howells wrote: > Willem de Bruijn wrote: > > > No need to modify __sys_sendmmsg explicitly, as it ends up calling > > __sys_sendmsg? > > > > Also, sendpage does this flags masking in the internal sock_FUNC > > helpers rather than __sys_FUNC. Might be preferable. > > I was wondering whether other flags, such as MSG_BATCH should be added to the > list. Is it bad if userspace sets that in sendmsg()? AF_KCM, at least, looks > at it. That flag was added exactly for AF_KCM. A process that explicitly sets it might experience bad behavior (increased latency), but there are no legacy AF_KCM applications that precede the flag.