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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 4DF42C433E1 for ; Thu, 13 Aug 2020 16:52:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 223C120829 for ; Thu, 13 Aug 2020 16:52:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726292AbgHMQws (ORCPT ); Thu, 13 Aug 2020 12:52:48 -0400 Received: from mx2.suse.de ([195.135.220.15]:53564 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726167AbgHMQwr (ORCPT ); Thu, 13 Aug 2020 12:52:47 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 1E54EADE1; Thu, 13 Aug 2020 16:53:09 +0000 (UTC) Received: by ds.suse.cz (Postfix, from userid 10065) id 72AB3DA6EF; Thu, 13 Aug 2020 18:51:44 +0200 (CEST) Date: Thu, 13 Aug 2020 18:51:44 +0200 From: David Sterba To: Josef Bacik Cc: linux-btrfs@vger.kernel.org, kernel-team@fb.com, Nikolay Borisov Subject: Re: [PATCH 15/23] btrfs: use ticketing for data space reservations Message-ID: <20200813165144.GQ2026@twin.jikos.cz> Reply-To: dsterba@suse.cz Mail-Followup-To: dsterba@suse.cz, Josef Bacik , linux-btrfs@vger.kernel.org, kernel-team@fb.com, Nikolay Borisov References: <20200721142234.2680-1-josef@toxicpanda.com> <20200721142234.2680-16-josef@toxicpanda.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200721142234.2680-16-josef@toxicpanda.com> User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Tue, Jul 21, 2020 at 10:22:26AM -0400, Josef Bacik wrote: > +static void priority_reclaim_data_space(struct btrfs_fs_info *fs_info, > + struct btrfs_space_info *space_info, > + struct reserve_ticket *ticket, > + const enum btrfs_flush_state *states, > + int states_nr) > +{ > + int flush_state = 0; > + int commit_cycles = 2; > + > + while (!space_info->full) { > + flush_space(fs_info, space_info, U64_MAX, ALLOC_CHUNK_FORCE); > + spin_lock(&space_info->lock); > + if (ticket->bytes == 0) { > + spin_unlock(&space_info->lock); > + return; > + } > + spin_unlock(&space_info->lock); > + } > +again: > + while (flush_state < states_nr) { > + u64 flush_bytes = U64_MAX; > + > + if (!commit_cycles) { > + if (states[flush_state] == FLUSH_DELALLOC_WAIT) { > + flush_state++; > + continue; > + } > + if (states[flush_state] == COMMIT_TRANS) > + flush_bytes = ticket->bytes; > + } > + > + flush_space(fs_info, space_info, flush_bytes, > + states[flush_state]); > + spin_lock(&space_info->lock); > + if (ticket->bytes == 0) { > + spin_unlock(&space_info->lock); > + return; > + } > + spin_unlock(&space_info->lock); > + flush_state++; > + } Actually, the whole logic in this loop could use some human readable description. There are 2 overlapping loops, one is over the states and the other are commit cycles, with some state-conditional changes. > + if (commit_cycles) { > + commit_cycles--; > + flush_state = 0; > + goto again; > + } > +}