From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Hellstrom Subject: Re: [PATCH] drm/ttm: do not check if list is empty in ttm_bo_force_list_clean, v2 Date: Fri, 30 Nov 2012 12:55:10 +0100 Message-ID: <50B89E9E.8070904@vmware.com> References: <50B868C1.8000703@canonical.com> <50B87695.2090606@vmware.com> <50B88790.6010208@canonical.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from smtp-outbound-2.vmware.com (smtp-outbound-2.vmware.com [208.91.2.13]) by gabe.freedesktop.org (Postfix) with ESMTP id 617B2E6079 for ; Fri, 30 Nov 2012 03:55:15 -0800 (PST) In-Reply-To: <50B88790.6010208@canonical.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org Errors-To: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org To: Maarten Lankhorst Cc: dri-devel@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org On 11/30/2012 11:16 AM, Maarten Lankhorst wrote: > Op 30-11-12 10:04, Thomas Hellstrom schreef: >> On 11/30/2012 09:05 AM, Maarten Lankhorst wrote: >>> Just use the return error from ttm_mem_evict_first instead. >>> >>> Changes since v1: >>> - Add warning if list is not empty, nothing else we can do here. >> Marten, when this function is called, all cross-device reservers have been shut out with the TTM lock or whatever similar >> mechanism is in place. It's a critical function that must succeed, unless there is a hardware failure to evict. >> >> As mentioned in the comments on the previous patch, ttm_bo_evict_first() may return 0 (OK) if it failed to reclaim the >> trylock in cleanup_refs_and_unlock(), with the assumption that another process will destroy the bo anyway >> (possibly at a later time which we know nothing about). The lru list needs to be empty when this function returns. >> >> This means we must either keep the while(list_empty) or perhaps better, retry instead of WARN if list_empty() is detected at the end of list. > As long as evict_first returns 0, that function is called over and over again Ah, ok. You're right. Reviewed-by: Thomas Hellstrom