From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: ARC-Seal: i=1; a=rsa-sha256; t=1516846002; cv=none; d=google.com; s=arc-20160816; b=Xx1toVl/BBmxb09dDAZZVje2r6AExavOO4rdEKUZIy+nYhu6HTar74u3RVdI5FoLAN M9uOYuplI1Lh+o0FhtKAxNG71nMPRlzxFI0XL/HAyaW8LuZoYx/iCvvU3b1cQSdPgF12 6wI/SX7vi0EtV5Vzhs5+lwKvFphsAdW3NzLwkr1YY8pz4Cl3HZyZyFeNGsi1FwmHb4nE SEP2tJIbRK9cQ9PCD4UXXt6vg5VITpz7imBTh226IWFy6Yu8dy2VM/ulI0r3UQhrbPea I+wcQG/2gyUCtUVYS+b1vVhMtPO9/A8nGuLdny6HoAuHGfYaiMzegeaCeK+s3T8ZlS9c mgZw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=cc:to:subject:message-id:date:from:references:in-reply-to :mime-version:dkim-signature:arc-authentication-results; bh=mM+JOCx9sP7TvUInyqG9YcvBjziB62UgeezUWhEp2DI=; b=L+AePMxOuJcxOn1T8BGGE5JsWqYqrT2BP8+kFTI/KB4HOnKtbpvQYXBOEpAsdtDdRG bZjAbX26NnTURx4CDnyn9IAlSjp8/XhbbA2WEtfracdIduoWbwKyVOQsqMRMLPvuPPou 91AVdQjJUj4xYNWoO5fBkJqn/Z6KUZgCOFZdzINcFv5tQMdJj9W0LJYipoYU1hAtagoN 6rqnpY0bGSVgneUKeDhVSX3AuYGmT84m+MUetbj/DmVGQZF/3B9guCjy7E9kQ7NdZLvf FZE1/9/ag6jzHD6TiqwP96P6pq22ZXqjPOrnaeBf6tI/jPSsB7fo66UnDt15yCX6ZzD4 q91Q== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=RJdtB44B; spf=pass (google.com: domain of opensource.ganesh@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=opensource.ganesh@gmail.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=gmail.com Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=RJdtB44B; spf=pass (google.com: domain of opensource.ganesh@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=opensource.ganesh@gmail.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=gmail.com X-Google-Smtp-Source: AH8x2247/d88oVgWNbYzAfkVG2wF7SMLDizZ3QtwLQjbrdsZJoZc3wowczFWXaqGTe6P61WH69QSf43scC0dxErpqQ8= MIME-Version: 1.0 In-Reply-To: References: <1515552545-18311-1-git-send-email-opensource.ganesh@gmail.com> <20180122155428.GB7714@kroah.com> From: Ganesh Mahendran Date: Thu, 25 Jan 2018 10:06:41 +0800 Message-ID: Subject: Re: [PATCH v3] android: binder: use VM_ALLOC to get vm area To: Todd Kjos Cc: Greg KH , Martijn Coenen , =?UTF-8?B?QXJ2ZSBIasO4bm5ldsOlZw==?= , LKML Content-Type: text/plain; charset="UTF-8" X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1589172035944979242?= X-GMAIL-MSGID: =?utf-8?q?1590528313769664022?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: Hi, Todd: 2018-01-23 1:02 GMT+08:00 Todd Kjos : > 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 for your review. > >> >> thanks, >> >> greg k-h