From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx182.postini.com [74.125.245.182]) by kanga.kvack.org (Postfix) with SMTP id 70A0D6B0002 for ; Wed, 24 Apr 2013 11:44:03 -0400 (EDT) Date: Wed, 24 Apr 2013 15:43:58 +0000 From: Christoph Lameter Subject: Re: Infiniband use of get_user_pages() In-Reply-To: <20130424153810.GA25958@quack.suse.cz> Message-ID: <0000013e3cb72e66-58330751-246a-4ac4-94d7-897754e59b3d-000000@email.amazonses.com> References: <20130424153810.GA25958@quack.suse.cz> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Jan Kara Cc: Roland Dreier , linux-rdma@vger.kernel.org, linux-mm@kvack.org On Wed, 24 Apr 2013, Jan Kara wrote: > Hello, > > when checking users of get_user_pages() (I'm doing some cleanups in that > area to fix filesystem's issues with mmap_sem locking) I've noticed that > infiniband drivers add number of pages obtained from get_user_pages() to > mm->pinned_vm counter. Although this makes some sence, it doesn't match > with any other user of get_user_pages() (e.g. direct IO) so has infiniband > some special reason why it does so? get_user_pages typically is used to temporarily increase the refcount. The Infiniband layer needs to permanently pin the pages for memory registration. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org