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[76.182.20.124]) by smtp.gmail.com with ESMTPSA id af79cd13be357-7a3785f4301sm194991485a.69.2024.08.08.13.55.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 08 Aug 2024 13:55:09 -0700 (PDT) Date: Thu, 8 Aug 2024 16:55:08 -0400 From: Josef Bacik To: Mateusz Guzik Cc: brauner@kernel.org, viro@zeniv.linux.org.uk, jack@suse.cz, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH] vfs: only read fops once in fops_get/put Message-ID: <20240808205508.GC625513@perftesting> References: <20240808155429.1080545-1-mjguzik@gmail.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240808155429.1080545-1-mjguzik@gmail.com> On Thu, Aug 08, 2024 at 05:54:28PM +0200, Mateusz Guzik wrote: > The compiler emits 2 access in fops_get(), put is patched to maintain some > consistency. > > This makes do_dentry_open() go down from 1177 to 1154 bytes. > > This popped up due to false-sharing where loads from inode->i_fop end up > bouncing a cacheline on parallel open. While this is going to be fixed, > the spurious load does not need to be there. > > No functional changes. > > Signed-off-by: Mateusz Guzik Reviewed-by: Josef Bacik Thanks, Josef