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[209.85.208.170]) by smtp.gmail.com with ESMTPSA id p10-v6sm15007636ljh.59.2019.01.09.17.18.38 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 09 Jan 2019 17:18:38 -0800 (PST) Received: by mail-lj1-f170.google.com with SMTP id t18-v6so8202115ljd.4 for ; Wed, 09 Jan 2019 17:18:38 -0800 (PST) X-Received: by 2002:a2e:95c6:: with SMTP id y6-v6mr4534294ljh.59.1547083117840; Wed, 09 Jan 2019 17:18:37 -0800 (PST) MIME-Version: 1.0 References: <20190106001138.GW6310@bombadil.infradead.org> <20190108044336.GB27534@dastard> <20190109022430.GE27534@dastard> <20190109043906.GF27534@dastard> <20190110004424.GH27534@dastard> In-Reply-To: <20190110004424.GH27534@dastard> From: Linus Torvalds Date: Wed, 9 Jan 2019 17:18:21 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] mm/mincore: allow for making sys_mincore() privileged To: Dave Chinner Cc: Jiri Kosina , Matthew Wilcox , Jann Horn , Andrew Morton , Greg KH , Peter Zijlstra , Michal Hocko , Linux-MM , kernel list , Linux API Content-Type: text/plain; charset="UTF-8" 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: Message-ID: <20190110011821.LVav8y44Uutbq46x3JLXPRN43e3H1uHcWGn2cTMUHCo@z> On Wed, Jan 9, 2019 at 4:44 PM Dave Chinner wrote: > > I wouldn't look at ext4 as an example of a reliable, problem free > direct IO implementation because, historically speaking, it's been a > series of nasty hacks (*cough* mount -o dioread_nolock *cough*) and > been far worse than XFS from data integrity, performance and > reliability perspectives. That's some big words from somebody who just admitted to much worse hacks. Seriously. XFS is buggy in this regard, ext4 apparently isn't. Thinking that it's better to just invalidate the cache for direct IO reads is all kinds of odd. Linus