From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qa0-f51.google.com (mail-qa0-f51.google.com [209.85.216.51]) by kanga.kvack.org (Postfix) with ESMTP id CCCBA6B0031 for ; Mon, 27 Jan 2014 03:00:05 -0500 (EST) Received: by mail-qa0-f51.google.com with SMTP id f11so6781077qae.24 for ; Mon, 27 Jan 2014 00:00:05 -0800 (PST) Received: from mail1.windriver.com (mail1.windriver.com. [147.11.146.13]) by mx.google.com with ESMTPS id ew5si6584257qab.135.2014.01.27.00.00.03 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 27 Jan 2014 00:00:04 -0800 (PST) Date: Mon, 27 Jan 2014 00:29:59 -0500 From: Paul Gortmaker Subject: Re: [PATCH] mm: bring back /sys/kernel/mm Message-ID: <20140127052959.GA20111@windriver.com> References: <20140127040330.GA17584@windriver.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Hugh Dickins Cc: Linus Torvalds , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org [Re: [PATCH] mm: bring back /sys/kernel/mm] On 26/01/2014 (Sun 21:02) Hugh Dickins wrote: > On Sun, 26 Jan 2014, Paul Gortmaker wrote: > > [[PATCH] mm: bring back /sys/kernel/mm] On 26/01/2014 (Sun 18:52) Hugh Dickins wrote: > > > > > Commit da29bd36224b ("mm/mm_init.c: make creation of the mm_kobj happen > > > earlier than device_initcall") changed to pure_initcall(mm_sysfs_init). > > > > > > That's too early: mm_sysfs_init() depends on core_initcall(ksysfs_init) > > > to have made the kernel_kobj directory "kernel" in which to create "mm". > > > > > > Make it postcore_initcall(mm_sysfs_init). We could use core_initcall(), > > > and depend upon Makefile link order kernel/ mm/ fs/ ipc/ security/ ... > > > as core_initcall(debugfs_init) and core_initcall(securityfs_init) do; > > > but better not. > > > > Agreed, N+1 is better than link order. I guess it silently fails then, > > with /sys/kernel/mm missing as the symptom? I'd booted i386 and ppc > > and didn't spot this, unfortunately... wondering now if there was a > > hint in dmesg that I simply failed to notice. > > No, nothing in dmesg at all: both mm_sysfs_init() and ksm_init() > (it was /sys/kernel/mm/ksm/run that I was looking for) thought > they had succeeded. > > Ah, I get it: it's normal to pass NULL parent to kobject_create_and_add(), > that just means create at the root. And when I look at an unfixed box, > yes, there's /sys/mm with all the right contents. Aha - yeah, I would have never seen that; the subtle rename is too easy to overlook unless one is used to going after some path by habit, and wonders why tab completion isn't working anymore... > > Given /sys/block and /sys/fs and /sys/kernel, I think /sys/mm is a better > location; but we're a few years too late to be making that change now ;) Agreed. Thanks again for the root cause, I don't feel so bad for missing it now. Paul. -- > > Hugh > > > > > > > > > Signed-off-by: Hugh Dickins > > > > Acked-by: Paul Gortmaker > > > > Thanks, > > Paul. > > > > > --- > > > > > > mm/mm_init.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > --- 3.13.0+/mm/mm_init.c 2014-01-23 21:51:26.004001378 -0800 > > > +++ linux/mm/mm_init.c 2014-01-26 18:06:40.488488209 -0800 > > > @@ -202,4 +202,4 @@ static int __init mm_sysfs_init(void) > > > > > > return 0; > > > } > > > -pure_initcall(mm_sysfs_init); > > > +postcore_initcall(mm_sysfs_init); -- 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