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AJvYcCUPpIlY9B8k7jAdjpsvW0dGCooUs2QbcHoY9pZtYJLlfKgSdv0dRX7k8N3vmAAZU0VWu3rJSijjew==@vger.kernel.org X-Gm-Message-State: AOJu0Yy/HlEVbTH0nLG4xhFO3xVEcngDx/EsiHpCLJFpGtyXI1zB0sgV AbwsVI05My7HiKw/O6iSiIfJXv2O4WNEVYHWt08GYv+SQztPs0Ptn0XtqrrX6Az/2/dDUcpgGVj 2P17TyinwaQaueuFhWZwO1hzHG+x4P6Q= X-Gm-Gg: AZuq6aJbahl+sWwfU/1CG58EGEpTABPHy5kT9fDQb/OF+zrWWVBXi5iYiQT3MTYnrMn SI6F0DJGaXFRUnFdCOIJz+Z8rmXbCHbvNWN9mXsPB9GnPER6rYkHbHQbA7WWSijVGVGcwFnMnlV eS7XMNZztev5aiHhTEm1V+ebrvZ+9NPubC0XcmG1cSC2DyG0XdQB7jsoQGJaT2zscfkIK4Ls/1+ JZQ0Hy5nanT0cc/bXe6OFLi7GrTgP9cMFwHX4wkRkYv/sJ/pqu8UMux9N26pPF/v0pTUQ== X-Received: by 2002:ac8:5fd2:0:b0:4f3:530f:d752 with SMTP id d75a77b69052e-506399e3540mr5186681cf.81.1770323461651; Thu, 05 Feb 2026 12:31:01 -0800 (PST) Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20260116233044.1532965-1-joannelkoong@gmail.com> <20260116233044.1532965-26-joannelkoong@gmail.com> <4b609081-89e9-41b7-bea2-b3fa4e8b9e3e@bsbernd.com> In-Reply-To: <4b609081-89e9-41b7-bea2-b3fa4e8b9e3e@bsbernd.com> From: Joanne Koong Date: Thu, 5 Feb 2026 12:30:50 -0800 X-Gm-Features: AZwV_Qg8zfQkLEaRSDbkx58VruVjYpcaGPLQvXOo3VEGvGW0ck6ffCgQN_OrEKc Message-ID: Subject: Re: [PATCH v4 25/25] docs: fuse: add io-uring bufring and zero-copy documentation To: Bernd Schubert Cc: axboe@kernel.dk, miklos@szeredi.hu, bschubert@ddn.com, csander@purestorage.com, krisman@suse.de, io-uring@vger.kernel.org, asml.silence@gmail.com, xiaobing.li@samsung.com, safinaskar@gmail.com, linux-fsdevel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, Feb 3, 2026 at 10:56=E2=80=AFAM Bernd Schubert = wrote: > > > > On 1/17/26 00:30, Joanne Koong wrote: > > Add documentation for fuse over io-uring usage of kernel-managed > > bufrings and zero-copy. > > > > Signed-off-by: Joanne Koong > > --- > > .../filesystems/fuse/fuse-io-uring.rst | 59 ++++++++++++++++++- > > 1 file changed, 58 insertions(+), 1 deletion(-) > > > > diff --git a/Documentation/filesystems/fuse/fuse-io-uring.rst b/Documen= tation/filesystems/fuse/fuse-io-uring.rst > > index d73dd0dbd238..11c244b63d25 100644 > > --- a/Documentation/filesystems/fuse/fuse-io-uring.rst > > +++ b/Documentation/filesystems/fuse/fuse-io-uring.rst > > @@ -95,5 +95,62 @@ Sending requests with CQEs > > | > | > > > +Kernel-managed buffer rings > > +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D > > > > - > > +Kernel-managed buffer rings have two main advantages: > > + > > +* eliminates the overhead of pinning/unpinning user pages and translat= ing > > + virtual addresses for every server-kernel interaction > > +* reduces buffer memory allocation requirements > > + > > +In order to use buffer rings, the server must preregister the followin= g: > > + > > +* a fixed buffer at index 0. This is where the headers will reside > > +* a kernel-managed buffer ring. This is where the payload will reside > > Would you mind to add the actual liburing call for this? I think it > would be helpful for anyone who wants to implement it. Good idea, I think what might be even more helpful is to refer them to the libfuse lib/lowlevel_fuse.c file for reference on how to set this up. Then they could just copy/paste the code directly from libfuse if they're trying to do something similar. I'll add this in for the next version. Thanks, Joanne > > > + > > +At a high-level, this is how fuse uses buffer rings: