Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754905Ab0KYAWW (ORCPT ); Wed, 24 Nov 2010 19:22:22 -0500 Received: from smtp-out.google.com ([74.125.121.35]:39135 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753638Ab0KYAWV convert rfc822-to-8bit (ORCPT ); Wed, 24 Nov 2010 19:22:21 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=google.com; s=beta; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type:content-transfer-encoding; b=gZLtRe96MmxLFLbQBD0gt73OnkloIkTIT6Ok9NnbfrT0a6d87rGxKIp9+YxUp+qcfE c8MekQ9RlIkYyIHi7ajg== MIME-Version: 1.0 In-Reply-To: References: <1290577024-12347-1-git-send-email-ccross@android.com> From: Paul Menage Date: Wed, 24 Nov 2010 16:21:58 -0800 Message-ID: Subject: Re: [PATCH 1/2] cgroup: Set CGRP_RELEASABLE when adding to a cgroup To: Colin Cross Cc: Li Zefan , containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1486 Lines: 35 On Wed, Nov 24, 2010 at 4:11 PM, Colin Cross wrote: >> >> We seem to have lost some notify_on_release() checks - maybe move that >> to check_for_release()? > check_for_release immediately calls cgroup_is_releasable, which checks > for the same bit as notify_on_release. ?There's no need for > CGRP_RELEASABLE to depend on notify_on_release, or to check > notify_on_release before calling check_for_release. OK. > I matched the existing behavior, __css_put sets CGRP_RELEASABLE when > refcnt goes to 0. > Ah, we do appear to have had that behaviour for a while. I don't remember the justification for it at this point :-) > check_for_release is only called from __css_put, cgroup_rmdir, and > __put_css_set (or free_css_set_work after my second patch). ?Those all > imply that __css_get, get_css_set, or cgroup_create have been > previously called, which are the functions that set CGRP_RELEASABLE. Not in one case - if we create a new cgroup and try to move a thread into it, but the thread is exiting as we move it, we'll call put_css_set() on the new css_set, which will drop the refcount on the target cgroup back to 0. We wouldn't want the auto-release notification to kick in in that situation, I think. Paul -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/