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[209.85.167.45]) by smtp.gmail.com with ESMTPSA id q67sm3442714ljq.110.2020.11.18.13.14.13 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 18 Nov 2020 13:14:14 -0800 (PST) Received: by mail-lf1-f45.google.com with SMTP id j205so5058336lfj.6 for ; Wed, 18 Nov 2020 13:14:13 -0800 (PST) X-Received: by 2002:a19:ae06:: with SMTP id f6mr4820439lfc.133.1605734053571; Wed, 18 Nov 2020 13:14:13 -0800 (PST) MIME-Version: 1.0 References: <20201118194838.753436396@linutronix.de> <20201118204007.028261233@linutronix.de> In-Reply-To: <20201118204007.028261233@linutronix.de> From: Linus Torvalds Date: Wed, 18 Nov 2020 13:13:57 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [patch V4 2/8] mm/highmem: Provide CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP To: Thomas Gleixner Cc: LKML , "the arch/x86 maintainers" , Christoph Hellwig , Matthew Wilcox , Daniel Vetter , Andrew Morton , Linux-MM , Peter Zijlstra , Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira 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, Nov 18, 2020 at 12:58 PM Thomas Gleixner wrote: > > Provide CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP which forces the temporary > mapping even for lowmem pages. This needs to be a seperate config switch > because this only works on architectures which do not have cache aliasing > problems. Very good. And you made sure to have a comment to not enable it for production systems. Hopefully people will even read it ;) Linus