From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx197.postini.com [74.125.245.197]) by kanga.kvack.org (Postfix) with SMTP id 0FC9D6B002B for ; Wed, 17 Oct 2012 19:54:03 -0400 (EDT) Date: Wed, 17 Oct 2012 16:54:01 -0700 From: Andrew Morton Subject: Re: [RFC PATCH v1 1/3] mm: teach mm by current context info to not do I/O during memory allocation Message-Id: <20121017165401.cc343861.akpm@linux-foundation.org> In-Reply-To: References: <1350403183-12650-1-git-send-email-ming.lei@canonical.com> <1350403183-12650-2-git-send-email-ming.lei@canonical.com> <20121016131933.c196457a.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Ming Lei Cc: linux-kernel@vger.kernel.org, Alan Stern , Oliver Neukum , Minchan Kim , Greg Kroah-Hartman , linux-usb@vger.kernel.org, linux-pm@vger.kernel.org, Jiri Kosina , Mel Gorman , KAMEZAWA Hiroyuki , Michal Hocko , Ingo Molnar , Peter Zijlstra , "Rafael J. Wysocki" , linux-mm On Wed, 17 Oct 2012 09:54:09 +0800 Ming Lei wrote: > On Wed, Oct 17, 2012 at 4:19 AM, Andrew Morton > wrote: > > > > The patch seems reasonable to me. I'd like to see some examples of > > these resume-time callsite which are performing the GFP_KERNEL > > allocations, please. You have found some kernel bugs, so those should > > be fully described. > > There are two examples on 2/3 and 3/3 of the patchset, see below link: > > http://marc.info/?l=linux-kernel&m=135040325717213&w=2 > http://marc.info/?l=linux-kernel&m=135040327317222&w=2 > > Sorry for not Cc them to linux-mm because I am afraid of making noise > in mm list. Don't worry about mailing list noise ;) > > > > This is just awful. Why oh why do we write code in macros when we have > > a nice C compiler? > > The two helpers are following style of local_irq_save() and > local_irq_restore(), so that people can use them easily, that is > why I define them as macro instead of inline. local_irq_save() and local_irq_restore() were mistakes :( It's silly to write what appears to be a C function and then have it operate like Pascal (warning: I last wrote some Pascal in 66 B.C.). > > > > These can all be done as nice, clean, type-safe, documented C > > functions. And if they can be done that way, they *should* be done > > that way! > > > > And I suggest that a better name for memalloc_noio_save() is > > memalloc_noio_set(). So this: > > IMO, renaming as memalloc_noio_set() might not be better than _save > because the _set name doesn't indicate that the flag should be stored first. You could add __must_check to the function definition to ensure that all callers save its return value. -- 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