From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1012EC433EF for ; Tue, 7 Sep 2021 12:07:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ED30D60698 for ; Tue, 7 Sep 2021 12:07:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229604AbhIGMIJ (ORCPT ); Tue, 7 Sep 2021 08:08:09 -0400 Received: from icebox.esperi.org.uk ([81.187.191.129]:43092 "EHLO mail.esperi.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343885AbhIGMII (ORCPT ); Tue, 7 Sep 2021 08:08:08 -0400 Received: from loom (nix@sidle.srvr.nix [192.168.14.8]) by mail.esperi.org.uk (8.16.1/8.16.1) with ESMTPS id 187C70P2019659 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Tue, 7 Sep 2021 13:07:00 +0100 From: Nix To: Coly Li Cc: linux-bcache@vger.kernel.org Subject: Re: 5.11: WARN on long-running system References: <87o89c4et5.fsf@esperi.org.uk> <52ea2e1a-041d-b182-f345-c8c531dd4613@suse.de> Emacs: The Awakening Date: Tue, 07 Sep 2021 13:07:00 +0100 In-Reply-To: <52ea2e1a-041d-b182-f345-c8c531dd4613@suse.de> (Coly Li's message of "Tue, 7 Sep 2021 12:12:43 +0800") Message-ID: <87h7ewy4gr.fsf@esperi.org.uk> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-DCC-wuwien-Metrics: loom 1290; Body=2 Fuz1=2 Fuz2=2 Precedence: bulk List-ID: X-Mailing-List: linux-bcache@vger.kernel.org On 7 Sep 2021, Coly Li verbalised: > On 9/1/21 9:15 PM, Nix wrote: >> It is notable that the unused % of this cache volume has fallen to only >> 3%: it's quite likely that this warning was emitted when it finally >> (after three years or so!) ran out of free space and did its first >> forced GC. I'm not sure how to tell. > Hi Nix, > > I have the similar feeling as yours, that it has been a long time after previous gc running. I have no idea why the gc didn't run > for such long time (this bucket was reused for 96 times). Let me try to find if there > is any clue why the gc does not work for such long time. It's probably just that my cache is 350GiB and it takes a long, long time to fill that up. (As in, the unused % has been falling slowly for three years and it's only just got close to zero in the last few months.) (Some GCs have run, but I have no idea why, given that when they ran the unused % was about 40%.)