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[209.85.167.46]) by smtp.gmail.com with ESMTPSA id d6sm2102109lfb.177.2020.09.20.16.32.14 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 20 Sep 2020 16:32:14 -0700 (PDT) Received: by mail-lf1-f46.google.com with SMTP id w11so12041614lfn.2 for ; Sun, 20 Sep 2020 16:32:14 -0700 (PDT) X-Received: by 2002:ac2:4a6a:: with SMTP id q10mr13257674lfp.534.1600644734040; Sun, 20 Sep 2020 16:32:14 -0700 (PDT) MIME-Version: 1.0 References: <20200912143704.GB6583@casper.infradead.org> <658ae026-32d9-0a25-5a59-9c510d6898d5@MichaelLarabel.com> <20200917182314.GU5449@casper.infradead.org> <20200917185049.GV5449@casper.infradead.org> <20200917192707.GW5449@casper.infradead.org> <20200920232303.GW12096@dread.disaster.area> In-Reply-To: <20200920232303.GW12096@dread.disaster.area> From: Linus Torvalds Date: Sun, 20 Sep 2020 16:31:57 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: Kernel Benchmarking To: Dave Chinner Cc: Matthew Wilcox , Michael Larabel , Matthieu Baerts , Amir Goldstein , "Ted Ts'o" , Andreas Dilger , Ext4 Developers List , Jan Kara , linux-fsdevel Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Sun, Sep 20, 2020 at 4:23 PM Dave Chinner wrote: > > FWIW, if the fs layer is already providing this level of IO > exclusion w.r.t. address space access, does it need to be replicated > at the address space level? Honestly, I'd rather do it the other way, and go "if the vfs layer were to provide the IO exclusion, maybe the filesystems can drop it? Because we end up having something like 60 different filesystems. It's *really* hard to know that "Yeah, this filesystem does it right". And if we do end up doing it at both levels, and end up having some of the locking duplicated, that's still better than "sometimes we don't do it at all", and have odd problems on the less usual (and often less well maintained) filesystems.. Linus