From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751189AbeAVRDB (ORCPT ); Mon, 22 Jan 2018 12:03:01 -0500 Received: from mail-io0-f196.google.com ([209.85.223.196]:35863 "EHLO mail-io0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751028AbeAVRDA (ORCPT ); Mon, 22 Jan 2018 12:03:00 -0500 X-Google-Smtp-Source: AH8x2254wosd3N+LrEow/hZzs4RbCOcDiejNoO+hhvFL9YxMIFR8w2yhnA5twKkMVRaXQtp7CBmwbos/msXLWvceUak= MIME-Version: 1.0 In-Reply-To: <20180122155428.GB7714@kroah.com> References: <1515552545-18311-1-git-send-email-opensource.ganesh@gmail.com> <20180122155428.GB7714@kroah.com> From: Todd Kjos Date: Mon, 22 Jan 2018 09:02:57 -0800 Message-ID: Subject: Re: [PATCH v3] android: binder: use VM_ALLOC to get vm area To: Greg KH Cc: Ganesh Mahendran , Martijn Coenen , =?UTF-8?B?QXJ2ZSBIasO4bm5ldsOlZw==?= , LKML Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 22, 2018 at 7:54 AM, Greg KH wrote: > On Wed, Jan 10, 2018 at 10:49:05AM +0800, Ganesh Mahendran wrote: >> VM_IOREMAP is used to access hardware through a mechanism called >> I/O mapped memory. Android binder is a IPC machanism which will >> not access I/O memory. >> >> And VM_IOREMAP has alignment requiement which may not needed in >> binder. >> __get_vm_area_node() >> { >> ... >> if (flags & VM_IOREMAP) >> align = 1ul << clamp_t(int, fls_long(size), >> PAGE_SHIFT, IOREMAP_MAX_ORDER); >> ... >> } >> >> This patch will save some kernel vm area, especially for 32bit os. >> >> In 32bit OS, kernel vm area is only 240MB. We may got below >> error when launching a app: >> >> <3>[ 4482.440053] binder_alloc: binder_alloc_mmap_handler: 15728 8ce67000-8cf65000 get_vm_area failed -12 >> <3>[ 4483.218817] binder_alloc: binder_alloc_mmap_handler: 15745 8ce67000-8cf65000 get_vm_area failed -12 >> >> Signed-off-by: Ganesh Mahendran >> ---- >> V3: update comments >> V2: update comments >> --- >> drivers/android/binder_alloc.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) > > Martijn and Todd, any objections to this patch? Looks fine to me. Arve, do you remember the rationale for using VM_IOREMAP? > > thanks, > > greg k-h