From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Arnd Bergmann To: Thierry Reding Subject: Re: [PATCH 05/14] lib: Add I/O map cache implementation Date: Wed, 9 Jan 2013 21:19:56 +0000 Cc: linux-tegra@vger.kernel.org, Grant Likely , Rob Herring , Russell King , Stephen Warren , Bjorn Helgaas , Andrew Murray , Jason Gunthorpe , Thomas Petazzoni , devicetree-discuss@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org References: <1357764194-12677-1-git-send-email-thierry.reding@avionic-design.de> <1357764194-12677-6-git-send-email-thierry.reding@avionic-design.de> In-Reply-To: <1357764194-12677-6-git-send-email-thierry.reding@avionic-design.de> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-15" Message-Id: <201301092119.57067.arnd@arndb.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: On Wednesday 09 January 2013, Thierry Reding wrote: > The I/O map cache is used to map large regions of physical memory in > smaller chunks to avoid running out of vmalloc()/ioremap() space. > > Signed-off-by: Thierry Reding Can you explain why this is necessary and which problem it solves? The implementation looks reasonable, but it's not clear to me if we really need this new interface. In what cases does it actually save ioremap space? Arnd From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH 05/14] lib: Add I/O map cache implementation Date: Wed, 9 Jan 2013 21:19:56 +0000 Message-ID: <201301092119.57067.arnd@arndb.de> References: <1357764194-12677-1-git-send-email-thierry.reding@avionic-design.de> <1357764194-12677-6-git-send-email-thierry.reding@avionic-design.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1357764194-12677-6-git-send-email-thierry.reding-RM9K5IK7kjKj5M59NBduVrNAH6kLmebB@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org Sender: "devicetree-discuss" To: Thierry Reding Cc: Jason Gunthorpe , Russell King , linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Rob Herring , Bjorn Helgaas , linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Andrew Murray , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: linux-tegra@vger.kernel.org On Wednesday 09 January 2013, Thierry Reding wrote: > The I/O map cache is used to map large regions of physical memory in > smaller chunks to avoid running out of vmalloc()/ioremap() space. > > Signed-off-by: Thierry Reding Can you explain why this is necessary and which problem it solves? The implementation looks reasonable, but it's not clear to me if we really need this new interface. In what cases does it actually save ioremap space? Arnd From mboxrd@z Thu Jan 1 00:00:00 1970 From: arnd@arndb.de (Arnd Bergmann) Date: Wed, 9 Jan 2013 21:19:56 +0000 Subject: [PATCH 05/14] lib: Add I/O map cache implementation In-Reply-To: <1357764194-12677-6-git-send-email-thierry.reding@avionic-design.de> References: <1357764194-12677-1-git-send-email-thierry.reding@avionic-design.de> <1357764194-12677-6-git-send-email-thierry.reding@avionic-design.de> Message-ID: <201301092119.57067.arnd@arndb.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wednesday 09 January 2013, Thierry Reding wrote: > The I/O map cache is used to map large regions of physical memory in > smaller chunks to avoid running out of vmalloc()/ioremap() space. > > Signed-off-by: Thierry Reding Can you explain why this is necessary and which problem it solves? The implementation looks reasonable, but it's not clear to me if we really need this new interface. In what cases does it actually save ioremap space? Arnd