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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 7A82CC04EB8 for ; Thu, 6 Dec 2018 16:43:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 37A3D20838 for ; Thu, 6 Dec 2018 16:43:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 37A3D20838 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-btrfs-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725898AbeLFQnv (ORCPT ); Thu, 6 Dec 2018 11:43:51 -0500 Received: from mx2.suse.de ([195.135.220.15]:33486 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725862AbeLFQnv (ORCPT ); Thu, 6 Dec 2018 11:43:51 -0500 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 1F096AEB2; Thu, 6 Dec 2018 16:43:48 +0000 (UTC) Subject: Re: [PATCH 09/10] btrfs: don't run delayed refs in the end transaction logic To: Josef Bacik , linux-btrfs@vger.kernel.org, kernel-team@fb.com References: <20181203152038.21388-1-josef@toxicpanda.com> <20181203152038.21388-10-josef@toxicpanda.com> From: Nikolay Borisov Openpgp: preference=signencrypt Autocrypt: addr=nborisov@suse.com; prefer-encrypt=mutual; keydata= xsFNBFiKBz4BEADNHZmqwhuN6EAzXj9SpPpH/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/ogKPk4ZxOXQEZetkEyTFghbRH2BIwARAQABzSJOaWtvbGF5IEJv cmlzb3YgPG5ib3Jpc292QHN1c2UuZGU+wsF4BBMBAgAiBQJYijkSAhsDBgsJCAcDAgYVCAIJ CgsEFgIDAQIeAQIXgAAKCRBxvoJG5T8oV/B6D/9a8EcRPdHg8uLEPywuJR8URwXzkofT5bZE IfGF0Z+Lt2ADe+nLOXrwKsamhweUFAvwEUxxnndovRLPOpWerTOAl47lxad08080jXnGfYFS Dc+ew7C3SFI4tFFHln8Y22Q9075saZ2yQS1ywJy+TFPADIprAZXnPbbbNbGtJLoq0LTiESnD w/SUC6sfikYwGRS94Dc9qO4nWyEvBK3Ql8NkoY0Sjky3B0vL572Gq0ytILDDGYuZVo4alUs8 LeXS5ukoZIw1QYXVstDJQnYjFxYgoQ5uGVi4t7FsFM/6ykYDzbIPNOx49Rbh9W4uKsLVhTzG BDTzdvX4ARl9La2kCQIjjWRg+XGuBM5rxT/NaTS78PXjhqWNYlGc5OhO0l8e5DIS2tXwYMDY LuHYNkkpMFksBslldvNttSNei7xr5VwjVqW4vASk2Aak5AleXZS+xIq2FADPS/XSgIaepyTV tkfnyreep1pk09cjfXY4A7qpEFwazCRZg9LLvYVc2M2eFQHDMtXsH59nOMstXx2OtNMcx5p8 0a5FHXE/HoXz3p9bD0uIUq6p04VYOHsMasHqHPbsMAq9V2OCytJQPWwe46bBjYZCOwG0+x58 fBFreP/NiJNeTQPOa6FoxLOLXMuVtpbcXIqKQDoEte9aMpoj9L24f60G4q+pL/54ql2VRscK d87BTQRYigc+ARAAyJSq9EFk28++SLfg791xOh28tLI6Yr8wwEOvM3wKeTfTZd+caVb9gBBy wxYhIopKlK1zq2YP7ZjTP1aPJGoWvcQZ8fVFdK/1nW+Z8/NTjaOx1mfrrtTGtFxVBdSCgqBB jHTnlDYV1R5plJqK+ggEP1a0mr/rpQ9dFGvgf/5jkVpRnH6BY0aYFPprRL8ZCcdv2DeeicOO YMobD5g7g/poQzHLLeT0+y1qiLIFefNABLN06Lf0GBZC5l8hCM3Rpb4ObyQ4B9PmL/KTn2FV Xq/c0scGMdXD2QeWLePC+yLMhf1fZby1vVJ59pXGq+o7XXfYA7xX0JsTUNxVPx/MgK8aLjYW hX+TRA4bCr4uYt/S3ThDRywSX6Hr1lyp4FJBwgyb8iv42it8KvoeOsHqVbuCIGRCXqGGiaeX Wa0M/oxN1vJjMSIEVzBAPi16tztL/wQtFHJtZAdCnuzFAz8ue6GzvsyBj97pzkBVacwp3/Mw qbiu7sDz7yB0d7J2tFBJYNpVt/Lce6nQhrvon0VqiWeMHxgtQ4k92Eja9u80JDaKnHDdjdwq FUikZirB28UiLPQV6PvCckgIiukmz/5ctAfKpyYRGfez+JbAGl6iCvHYt/wAZ7Oqe/3Cirs5 KhaXBcMmJR1qo8QH8eYZ+qhFE3bSPH446+5oEw8A9v5oonKV7zMAEQEAAcLBXwQYAQIACQUC WIoHPgIbDAAKCRBxvoJG5T8oV1pyD/4zdXdOL0lhkSIjJWGqz7Idvo0wjVHSSQCbOwZDWNTN JBTP0BUxHpPu/Z8gRNNP9/k6i63T4eL1xjy4umTwJaej1X15H8Hsh+zakADyWHadbjcUXCkg OJK4NsfqhMuaIYIHbToi9K5pAKnV953xTrK6oYVyd/Rmkmb+wgsbYQJ0Ur1Ficwhp6qU1CaJ mJwFjaWaVgUERoxcejL4ruds66LM9Z1Qqgoer62ZneID6ovmzpCWbi2sfbz98+kW46aA/w8r 7sulgs1KXWhBSv5aWqKU8C4twKjlV2XsztUUsyrjHFj91j31pnHRklBgXHTD/pSRsN0UvM26 lPs0g3ryVlG5wiZ9+JbI3sKMfbdfdOeLxtL25ujs443rw1s/PVghphoeadVAKMPINeRCgoJH zZV/2Z/myWPRWWl/79amy/9MfxffZqO9rfugRBORY0ywPHLDdo9Kmzoxoxp9w3uTrTLZaT9M KIuxEcV8wcVjr+Wr9zRl06waOCkgrQbTPp631hToxo+4rA1jiQF2M80HAet65ytBVR2pFGZF zGYYLqiG+mpUZ+FPjxk9kpkRYz61mTLSY7tuFljExfJWMGfgSg1OxfLV631jV1TcdUnx+h3l Sqs2vMhAVt14zT8mpIuu2VNxcontxgVr1kzYA/tQg32fVRbGr449j1gw57BV9i0vww== Message-ID: Date: Thu, 6 Dec 2018 18:43:46 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20181203152038.21388-10-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 3.12.18 г. 17:20 ч., Josef Bacik wrote: > Over the years we have built up a lot of infrastructure to keep delayed > refs in check, mostly by running them at btrfs_end_transaction() time. > We have a lot of different maths we do to figure out how much, if we > should do it inline or async, etc. This existed because we had no > feedback mechanism to force the flushing of delayed refs when they > became a problem. However with the enospc flushing infrastructure in > place for flushing delayed refs when they put too much pressure on the > enospc system we have this problem solved. Rip out all of this code as > it is no longer needed. > > Signed-off-by: Josef Bacik > --- > fs/btrfs/transaction.c | 38 -------------------------------------- > 1 file changed, 38 deletions(-) > > diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c > index 2d8401bf8df9..01f39401619a 100644 > --- a/fs/btrfs/transaction.c > +++ b/fs/btrfs/transaction.c > @@ -798,22 +798,12 @@ static int should_end_transaction(struct btrfs_trans_handle *trans) > int btrfs_should_end_transaction(struct btrfs_trans_handle *trans) > { > struct btrfs_transaction *cur_trans = trans->transaction; > - int updates; > - int err; > > smp_mb(); > if (cur_trans->state >= TRANS_STATE_BLOCKED || > cur_trans->delayed_refs.flushing) > return 1; > > - updates = trans->delayed_ref_updates; > - trans->delayed_ref_updates = 0; > - if (updates) { > - err = btrfs_run_delayed_refs(trans, updates * 2); > - if (err) /* Error code will also eval true */ > - return err; > - } > - > return should_end_transaction(trans); > } > > @@ -843,11 +833,8 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans, > { > struct btrfs_fs_info *info = trans->fs_info; > struct btrfs_transaction *cur_trans = trans->transaction; > - u64 transid = trans->transid; > - unsigned long cur = trans->delayed_ref_updates; > int lock = (trans->type != TRANS_JOIN_NOLOCK); > int err = 0; > - int must_run_delayed_refs = 0; > > if (refcount_read(&trans->use_count) > 1) { > refcount_dec(&trans->use_count); > @@ -858,27 +845,6 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans, > btrfs_trans_release_metadata(trans); > trans->block_rsv = NULL; > > - if (!list_empty(&trans->new_bgs)) > - btrfs_create_pending_block_groups(trans); Is this being deleted because in delayed_refs_rsv you account also fo new block groups? > - > - trans->delayed_ref_updates = 0; > - if (!trans->sync) { > - must_run_delayed_refs = > - btrfs_should_throttle_delayed_refs(trans); > - cur = max_t(unsigned long, cur, 32); > - > - /* > - * don't make the caller wait if they are from a NOLOCK > - * or ATTACH transaction, it will deadlock with commit > - */ > - if (must_run_delayed_refs == 1 && > - (trans->type & (__TRANS_JOIN_NOLOCK | __TRANS_ATTACH))) > - must_run_delayed_refs = 2; > - } > - > - btrfs_trans_release_metadata(trans); > - trans->block_rsv = NULL; Why remove those 2 lines as well ? > - > if (!list_empty(&trans->new_bgs)) > btrfs_create_pending_block_groups(trans); > > @@ -923,10 +889,6 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans, > } > > kmem_cache_free(btrfs_trans_handle_cachep, trans); > - if (must_run_delayed_refs) { > - btrfs_async_run_delayed_refs(info, cur, transid, > - must_run_delayed_refs == 1); > - } > return err; > } > >