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[209.85.167.51]) by smtp.gmail.com with ESMTPSA id t6sm1977750ljj.62.2019.12.11.17.09.09 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 11 Dec 2019 17:09:10 -0800 (PST) Received: by mail-lf1-f51.google.com with SMTP id 9so310178lfq.10 for ; Wed, 11 Dec 2019 17:09:09 -0800 (PST) X-Received: by 2002:a19:4351:: with SMTP id m17mr4171510lfj.61.1576112949682; Wed, 11 Dec 2019 17:09:09 -0800 (PST) MIME-Version: 1.0 References: <20191211152943.2933-1-axboe@kernel.dk> <0d4e3954-c467-30a7-5a8e-7c4180275533@kernel.dk> In-Reply-To: From: Linus Torvalds Date: Wed, 11 Dec 2019 17:08:53 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCHSET v3 0/5] Support for RWF_UNCACHED To: Jens Axboe Cc: Linux-MM , linux-fsdevel , linux-block , Matthew Wilcox , Chris Mason , Dave Chinner , Johannes Weiner 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: On Wed, Dec 11, 2019 at 3:41 PM Jens Axboe wrote: > > Here's what I did to reproduce: Gaah. I have a fairly fast ssd (but it's "consumer fast" - Samsung 970 Pro - I'm assuming yours is a different class), but I encrypt my disk, so I only get about 15k iops and I see kcyrptd in my profiles, not kswapd. I didn't even try to worry about RWF_UNCACHED or RWF_NOACCESS, since I wanted to see the problem. But I think that with my setup, I can't really see it just due to my IO being slow ;( I do see xas_create and kswapd0, but it's 0.42%. I'm assuming it's the very first signs of this problem, but it's certainly not all that noticeable. Linus