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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham 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 019E2C3A5A0 for ; Mon, 19 Aug 2019 14:49:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CB6952070D for ; Mon, 19 Aug 2019 14:49:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726670AbfHSOts (ORCPT ); Mon, 19 Aug 2019 10:49:48 -0400 Received: from mx2.suse.de ([195.135.220.15]:52696 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726168AbfHSOts (ORCPT ); Mon, 19 Aug 2019 10:49:48 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id D4A18AE72; Mon, 19 Aug 2019 14:49:46 +0000 (UTC) Subject: Re: [PATCH 6/8] btrfs: rework wake_all_tickets To: Josef Bacik , kernel-team@fb.com, linux-btrfs@vger.kernel.org References: <20190816141952.19369-1-josef@toxicpanda.com> <20190816141952.19369-7-josef@toxicpanda.com> From: Nikolay Borisov Openpgp: preference=signencrypt Autocrypt: addr=nborisov@suse.com; prefer-encrypt=mutual; keydata= mQINBFiKBz4BEADNHZmqwhuN6EAzXj9SpPpH/nSSP8YgfwoOqwrP+JR4pIqRK0AWWeWCSwmZ T7g+RbfPFlmQp+EwFWOtABXlKC54zgSf+uulGwx5JAUFVUIRBmnHOYi/lUiE0yhpnb1KCA7f u/W+DkwGerXqhhe9TvQoGwgCKNfzFPZoM+gZrm+kWv03QLUCr210n4cwaCPJ0Nr9Z3c582xc bCUVbsjt7BN0CFa2BByulrx5xD9sDAYIqfLCcZetAqsTRGxM7LD0kh5WlKzOeAXj5r8DOrU2 GdZS33uKZI/kZJZVytSmZpswDsKhnGzRN1BANGP8sC+WD4eRXajOmNh2HL4P+meO1TlM3GLl EQd2shHFY0qjEo7wxKZI1RyZZ5AgJnSmehrPCyuIyVY210CbMaIKHUIsTqRgY5GaNME24w7h TyyVCy2qAM8fLJ4Vw5bycM/u5xfWm7gyTb9V1TkZ3o1MTrEsrcqFiRrBY94Rs0oQkZvunqia c+NprYSaOG1Cta14o94eMH271Kka/reEwSZkC7T+o9hZ4zi2CcLcY0DXj0qdId7vUKSJjEep c++s8ncFekh1MPhkOgNj8pk17OAESanmDwksmzh1j12lgA5lTFPrJeRNu6/isC2zyZhTwMWs k3LkcTa8ZXxh0RfWAqgx/ogKPk4ZxOXQEZetkEyTFghbRH2BIwARAQABtCNOaWtvbGF5IEJv cmlzb3YgPG5ib3Jpc292QHN1c2UuY29tPokCOAQTAQIAIgUCWIo48QIbAwYLCQgHAwIGFQgC CQoLBBYCAwECHgECF4AACgkQcb6CRuU/KFc0eg/9GLD3wTQz9iZHMFbjiqTCitD7B6dTLV1C ddZVlC8Hm/TophPts1bWZORAmYIihHHI1EIF19+bfIr46pvfTu0yFrJDLOADMDH+Ufzsfy2v HSqqWV/nOSWGXzh8bgg/ncLwrIdEwBQBN9SDS6aqsglagvwFD91UCg/TshLlRxD5BOnuzfzI Leyx2c6YmH7Oa1R4MX9Jo79SaKwdHt2yRN3SochVtxCyafDlZsE/efp21pMiaK1HoCOZTBp5 VzrIP85GATh18pN7YR9CuPxxN0V6IzT7IlhS4Jgj0NXh6vi1DlmKspr+FOevu4RVXqqcNTSS E2rycB2v6cttH21UUdu/0FtMBKh+rv8+yD49FxMYnTi1jwVzr208vDdRU2v7Ij/TxYt/v4O8 V+jNRKy5Fevca/1xroQBICXsNoFLr10X5IjmhAhqIH8Atpz/89ItS3+HWuE4BHB6RRLM0gy8 T7rN6ja+KegOGikp/VTwBlszhvfLhyoyjXI44Tf3oLSFM+8+qG3B7MNBHOt60CQlMkq0fGXd mm4xENl/SSeHsiomdveeq7cNGpHi6i6ntZK33XJLwvyf00PD7tip/GUj0Dic/ZUsoPSTF/mG EpuQiUZs8X2xjK/AS/l3wa4Kz2tlcOKSKpIpna7V1+CMNkNzaCOlbv7QwprAerKYywPCoOSC 7P25Ag0EWIoHPgEQAMiUqvRBZNvPvki34O/dcTodvLSyOmK/MMBDrzN8Cnk302XfnGlW/YAQ csMWISKKSpStc6tmD+2Y0z9WjyRqFr3EGfH1RXSv9Z1vmfPzU42jsdZn667UxrRcVQXUgoKg QYx055Q2FdUeaZSaivoIBD9WtJq/66UPXRRr4H/+Y5FaUZx+gWNGmBT6a0S/GQnHb9g3nonD jmDKGw+YO4P6aEMxyy3k9PstaoiyBXnzQASzdOi39BgWQuZfIQjN0aW+Dm8kOAfT5i/yk59h VV6v3NLHBjHVw9kHli3jwvsizIX9X2W8tb1SefaVxqvqO1132AO8V9CbE1DcVT8fzICvGi42 FoV/k0QOGwq+LmLf0t04Q0csEl+h69ZcqeBSQcIMm/Ir+NorfCr6HjrB6lW7giBkQl6hhomn l1mtDP6MTdbyYzEiBFcwQD4terc7S/8ELRRybWQHQp7sxQM/Lnuhs77MgY/e6c5AVWnMKd/z MKm4ru7A8+8gdHeydrRQSWDaVbfy3Hup0Ia76J9FaolnjB8YLUOJPdhI2vbvNCQ2ipxw3Y3c KhVIpGYqwdvFIiz0Fej7wnJICIrpJs/+XLQHyqcmERn3s/iWwBpeogrx2Lf8AGezqnv9woq7 OSoWlwXDJiUdaqPEB/HmGfqoRRN20jx+OOvuaBMPAPb+aKJyle8zABEBAAGJAh8EGAECAAkF AliKBz4CGwwACgkQcb6CRuU/KFdacg/+M3V3Ti9JYZEiIyVhqs+yHb6NMI1R0kkAmzsGQ1jU zSQUz9AVMR6T7v2fIETTT/f5Oout0+Hi9cY8uLpk8CWno9V9eR/B7Ifs2pAA8lh2nW43FFwp IDiSuDbH6oTLmiGCB206IvSuaQCp1fed8U6yuqGFcnf0ZpJm/sILG2ECdFK9RYnMIaeqlNQm iZicBY2lmlYFBEaMXHoy+K7nbOuizPWdUKoKHq+tmZ3iA+qL5s6Qlm4trH28/fPpFuOmgP8P K+7LpYLNSl1oQUr+WlqilPAuLcCo5Vdl7M7VFLMq4xxY/dY99aZx0ZJQYFx0w/6UkbDdFLzN upT7NIN68lZRucImffiWyN7CjH23X3Tni8bS9ubo7OON68NbPz1YIaYaHmnVQCjDyDXkQoKC R82Vf9mf5slj0Vlpf+/Wpsv/TH8X32ajva37oEQTkWNMsDxyw3aPSps6MaMafcN7k60y2Wk/ TCiLsRHFfMHFY6/lq/c0ZdOsGjgpIK0G0z6et9YU6MaPuKwNY4kBdjPNBwHreucrQVUdqRRm RcxmGC6ohvpqVGfhT48ZPZKZEWM+tZky0mO7bhZYxMXyVjBn4EoNTsXy1et9Y1dU3HVJ8fod 5UqrNrzIQFbdeM0/JqSLrtlTcXKJ7cYFa9ZM2AP7UIN9n1UWxq+OPY9YMOewVfYtL8M= Message-ID: <92c9dda1-bc57-48b5-e3d1-2a0af4e56adb@suse.com> Date: Mon, 19 Aug 2019 17:49:45 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190816141952.19369-7-josef@toxicpanda.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 16.08.19 г. 17:19 ч., Josef Bacik wrote: > Now that we no longer partially fill tickets we need to rework > wake_all_tickets to call btrfs_try_to_wakeup_tickets() in order to see > if any subsequent tickets are able to be satisfied. If our tickets_id > changes we know something happened and we can keep flushing. > > Also if we find a ticket that is smaller than the first ticket in our > queue then we want to retry the flushing loop again in case > may_commit_transaction() decides we could satisfy the ticket by > committing the transaction. > > Signed-off-by: Josef Bacik > --- > fs/btrfs/space-info.c | 34 +++++++++++++++++++++++++++------- > 1 file changed, 27 insertions(+), 7 deletions(-) > > diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c > index 8a1c7ada67cb..bd485be783b8 100644 > --- a/fs/btrfs/space-info.c > +++ b/fs/btrfs/space-info.c > @@ -676,19 +676,39 @@ static inline int need_do_async_reclaim(struct btrfs_fs_info *fs_info, > !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state)); > } > > -static bool wake_all_tickets(struct list_head *head) > +static bool wake_all_tickets(struct btrfs_fs_info *fs_info, > + struct btrfs_space_info *space_info) > { > struct reserve_ticket *ticket; > + u64 tickets_id = space_info->tickets_id; > + u64 first_ticket_bytes = 0; > + > + while (!list_empty(&space_info->tickets) && > + tickets_id == space_info->tickets_id) { > + ticket = list_first_entry(&space_info->tickets, > + struct reserve_ticket, list); > + > + /* > + * may_commit_transaction will avoid committing the transaction > + * if it doesn't feel like the space reclaimed by the commit > + * would result in the ticket succeeding. However if we have a > + * smaller ticket in the queue it may be small enough to be > + * satisified by committing the transaction, so if any > + * subsequent ticket is smaller than the first ticket go ahead > + * and send us back for another loop through the enospc flushing > + * code. > + */ > + if (first_ticket_bytes == 0) > + first_ticket_bytes = ticket->bytes; > + else if (first_ticket_bytes > ticket->bytes) > + return true; > > - while (!list_empty(head)) { > - ticket = list_first_entry(head, struct reserve_ticket, list); > list_del_init(&ticket->list); > ticket->error = -ENOSPC; > wake_up(&ticket->wait); > - if (ticket->bytes != ticket->orig_bytes) > - return true; > + btrfs_try_to_wakeup_tickets(fs_info, space_info); So the change in this logic is directly related to the implementation of btrfs_try_to_wakeup_tickets. Because when we fail and remove a ticket in this function we give a chance that the next ticket *could* be satisfied. But how well does that work in practice, given you fail normal prio tickets here, whereas btrfs_try_to_wakeup_tickets first checks the prio ticket. So even if you are failing normal ticket but there is one unsatifiable prio ticket that won't really change anything. > } > - return false; > + return (tickets_id != space_info->tickets_id); > } > > /* > @@ -756,7 +776,7 @@ static void btrfs_async_reclaim_metadata_space(struct work_struct *work) > if (flush_state > COMMIT_TRANS) { > commit_cycles++; > if (commit_cycles > 2) { > - if (wake_all_tickets(&space_info->tickets)) { > + if (wake_all_tickets(fs_info, space_info)) { > flush_state = FLUSH_DELAYED_ITEMS_NR; > commit_cycles--; > } else { >