From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx171.postini.com [74.125.245.171]) by kanga.kvack.org (Postfix) with SMTP id 644266B0033 for ; Wed, 15 May 2013 19:05:34 -0400 (EDT) Date: Wed, 15 May 2013 16:05:32 -0700 From: Andrew Morton Subject: Re: [RFC PATCH 0/2] return value from shrinkers Message-Id: <20130515160532.c965e92707c354100e25f79b@linux-foundation.org> In-Reply-To: <1368454595-5121-1-git-send-email-oskar.andero@sonymobile.com> References: <1368454595-5121-1-git-send-email-oskar.andero@sonymobile.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Oskar Andero Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Hugh Dickins , Greg Kroah-Hartman , Radovan Lekanovic , David Rientjes On Mon, 13 May 2013 16:16:33 +0200 Oskar Andero wrote: > In a previous discussion on lkml it was noted that the shrinkers use the > magic value "-1" to signal that something went wrong. > > This patch-set implements the suggestion of instead using errno.h values > to return something more meaningful. > > The first patch simply changes the check from -1 to any negative value and > updates the comment accordingly. > > The second patch updates the shrinkers to return an errno.h value instead > of -1. Since this one spans over many different areas I need input on what is > a meaningful return value. Right now I used -EBUSY on everything for consitency. > > What do you say? Is this a good idea or does it make no sense at all? I don't see much point in it, really. Returning an errno implies that the errno will eventually be returned to userspace. But that isn't the case, so such a change is somewhat misleading. If we want the capability to return more than a binary yes/no message to callers then yes, we could/should enumerate the shrinker return values. But as that is a different concept from errnos, it should be done with a different and shrinker-specific namespace. -- 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