From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id 9D0CC6B004A for ; Tue, 9 Nov 2010 18:56:02 -0500 (EST) Received: from hpaq2.eem.corp.google.com (hpaq2.eem.corp.google.com [172.25.149.2]) by smtp-out.google.com with ESMTP id oA9NtxpQ031045 for ; Tue, 9 Nov 2010 15:56:00 -0800 Received: from pwi1 (pwi1.prod.google.com [10.241.219.1]) by hpaq2.eem.corp.google.com with ESMTP id oA9NtvXC005426 for ; Tue, 9 Nov 2010 15:55:58 -0800 Received: by pwi1 with SMTP id 1so17405pwi.0 for ; Tue, 09 Nov 2010 15:55:57 -0800 (PST) Date: Tue, 9 Nov 2010 15:55:53 -0800 (PST) From: David Rientjes Subject: [patch] oom: document obsolete oom_adj tunable In-Reply-To: Message-ID: References: <20101101030353.607A.A69D9226@jp.fujitsu.com> <20101109105801.BC30.A69D9226@jp.fujitsu.com> <20101109233541.13be4cd5@lxorguk.ukuu.org.uk> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: Alan Cox Cc: KOSAKI Motohiro , Andrew Morton , Linus Torvalds , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: /proc/pid/oom_adj was deprecated in August 2010 with the introduction of the new oom killer heuristic. This patch copies the Documentation/feature-removal-schedule.txt entry for this tunable to the Documentation/ABI/obsolete directory so nobody misses it. Reported-by: Alan Cox Signed-off-by: David Rientjes --- Documentation/ABI/obsolete/proc-pid-oom_adj | 22 ++++++++++++++++++++++ 1 files changed, 22 insertions(+), 0 deletions(-) create mode 100644 Documentation/ABI/obsolete/proc-pid-oom_adj diff --git a/Documentation/ABI/obsolete/proc-pid-oom_adj b/Documentation/ABI/obsolete/proc-pid-oom_adj new file mode 100644 --- /dev/null +++ b/Documentation/ABI/obsolete/proc-pid-oom_adj @@ -0,0 +1,22 @@ +What: /proc//oom_adj +When: August 2012 +Why: /proc//oom_adj allows userspace to influence the oom killer's + badness heuristic used to determine which task to kill when the kernel + is out of memory. + + The badness heuristic has since been rewritten since the introduction of + this tunable such that its meaning is deprecated. The value was + implemented as a bitshift on a score generated by the badness() + function that did not have any precise units of measure. With the + rewrite, the score is given as a proportion of available memory to the + task allocating pages, so using a bitshift which grows the score + exponentially is, thus, impossible to tune with fine granularity. + + A much more powerful interface, /proc//oom_score_adj, was + introduced with the oom killer rewrite that allows users to increase or + decrease the badness() score linearly. This interface will replace + /proc//oom_adj. + + A warning will be emitted to the kernel log if an application uses this + deprecated interface. After it is printed once, future warnings will be + suppressed until the kernel is rebooted. -- 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/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org