From patchwork Sun Aug 28 06:46:20 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ojaswin Mujoo X-Patchwork-Id: 12957188 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A083AC0502C for ; Sun, 28 Aug 2022 06:47:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232721AbiH1Gry (ORCPT ); Sun, 28 Aug 2022 02:47:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44576 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232730AbiH1GrK (ORCPT ); Sun, 28 Aug 2022 02:47:10 -0400 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 97FCB4B0E8; Sat, 27 Aug 2022 23:46:57 -0700 (PDT) Received: from pps.filterd (m0127361.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 27S5UJ7i014363; Sun, 28 Aug 2022 06:46:53 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=pp1; bh=uENFlqe3snIfemnzRDx+h9KZz/ql4+PmbUX2EFV/ZBo=; b=cuCMB3H0WSiR7m4EfqAdUJmmO30e0550pALIxP+08JjH/iy+VpBmvF2adTT/W97uQG5A QA9vrpeH+fvgtETBmfGleHSVq3dcfIdy69XaoidtYZVVRikN0l9YgHUgUdQ/Nw6fJ/q0 XW/20asHdh5yuMbppf37wT2AanwfQCikgh9MzChjc47v4qDbtYK2xQG+JhcrJPC1EHWl FfVHDpatTEOcd5d3IVENRaAJ+HqRsfZMPh6s7JWCe7LkdUX+0r4CyzmCXtDa9fzsQGYu LxV6/6VlXz49HDsXhL1vu2h0lSwmpS/0skQbUjIXXR5Miahsfe3kCBRS69OQktIl3qzH 0Q== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3j7waq83yc-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 28 Aug 2022 06:46:53 +0000 Received: from m0127361.ppops.net (m0127361.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 27S6jUa3030562; Sun, 28 Aug 2022 06:46:53 GMT Received: from ppma04ams.nl.ibm.com (63.31.33a9.ip4.static.sl-reverse.com [169.51.49.99]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3j7waq83xt-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 28 Aug 2022 06:46:52 +0000 Received: from pps.filterd (ppma04ams.nl.ibm.com [127.0.0.1]) by ppma04ams.nl.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 27S6ZL8M015370; Sun, 28 Aug 2022 06:46:50 GMT Received: from b06cxnps4075.portsmouth.uk.ibm.com (d06relay12.portsmouth.uk.ibm.com [9.149.109.197]) by ppma04ams.nl.ibm.com with ESMTP id 3j7aw8s16s-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 28 Aug 2022 06:46:50 +0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 27S6km0R36176290 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sun, 28 Aug 2022 06:46:48 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5C12852051; Sun, 28 Aug 2022 06:46:48 +0000 (GMT) Received: from li-bb2b2a4c-3307-11b2-a85c-8fa5c3a69313.ibm.com (unknown [9.43.118.96]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id 294825204E; Sun, 28 Aug 2022 06:46:45 +0000 (GMT) From: Ojaswin Mujoo To: linux-ext4@vger.kernel.org Cc: "Theodore Ts'o" , Ritesh Harjani , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Andreas Dilger , Ritesh Harjani Subject: [RFC 7/8] ext4: Use rbtrees to manage PAs instead of inode i_prealloc_list Date: Sun, 28 Aug 2022 12:16:20 +0530 Message-Id: <35676d73c905e80165aaad9ff9c337662edefe3a.1661632343.git.ojaswin@linux.ibm.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: References: MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: G7nxXXsU_qOPgmyTwPBbq0SAeJf2VX7G X-Proofpoint-GUID: gFoM9xoEQRyMCNYn0BoOjldn9bpInEuw X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.517,FMLib:17.11.122.1 definitions=2022-08-27_10,2022-08-25_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 phishscore=0 suspectscore=0 mlxlogscore=999 adultscore=0 malwarescore=0 bulkscore=0 priorityscore=1501 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2207270000 definitions=main-2208280025 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Currently, the kernel uses i_prealloc_list to hold all the inode preallocations. This is known to cause degradation in performance in workloads which perform large number of sparse writes on a single file. This is mainly because functions like ext4_mb_normalize_request() and ext4_mb_use_preallocated() iterate over this complete list, resulting in slowdowns when large number of PAs are present. Patch 27bc446e2 partially fixed this by enforcing a limit of 512 for the inode preallocation list and adding logic to continually trim the list if it grows above the threshold, however our testing revealed that a hardcoded value is not suitable for all kinds of workloads. To optimize this, add an rbtree to the inode and hold the inode preallocations in this rbtree. This will make iterating over inode PAs faster and scale much better than a linked list. Additionally, we also had to remove the LRU logic that was added during trimming of the list (in ext4_mb_release_context()) as it will add extra overhead in rbtree. The discards now happen in the lowest-logical-offset-first order. ** Locking notes ** With the introduction of rbtree to maintain inode PAs, we can't use RCU to walk the tree for searching since it can result in partial traversals which might miss some nodes(or entire subtrees) while discards happen in parallel (which happens under a lock). Hence this patch converts the ei->i_prealloc_lock spin_lock to rw_lock. Almost all the codepaths that read/modify the PA rbtrees are protected by the higher level inode->i_data_sem (except ext4_mb_discard_group_preallocations() and ext4_clear_inode()) IIUC, the only place we need lock protection is when one thread is reading "searching" the PA rbtree (earlier protected under rcu_read_lock()) and another is "deleting" the PAs in ext4_mb_discard_group_preallocations() function (which iterates all the PAs using the grp->bb_prealloc_list and deletes PAs from the tree without taking any inode lock (i_data_sem)). So, this patch converts all rcu_read_lock/unlock() paths for inode list PA to use read_lock() and all places where we were using ei->i_prealloc_lock spinlock will now be using write_lock(). Note that this makes the fast path (searching of the right PA e.g. ext4_mb_use_preallocated() or ext4_mb_normalize_request()), now use read_lock() instead of rcu_read_lock/unlock(). Ths also will now block due to slow discard path (ext4_mb_discard_group_preallocations()) which uses write_lock(). But this is not as bad as it looks. This is because - 1. The slow path only occurs when the normal allocation failed and we can say that we are low on disk space. One can argue this scenario won't be much frequent. 2. ext4_mb_discard_group_preallocations(), locks and unlocks the rwlock for deleting every individual PA. This gives enough opportunity for the fast path to acquire the read_lock for searching the PA inode list. Signed-off-by: Ojaswin Mujoo Reviewed-by: Ritesh Harjani (IBM) --- fs/ext4/ext4.h | 4 +- fs/ext4/mballoc.c | 175 ++++++++++++++++++++++++++++++---------------- fs/ext4/mballoc.h | 6 +- fs/ext4/super.c | 4 +- 4 files changed, 123 insertions(+), 66 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 310e976ef1fd..acfca7b1fe92 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1111,8 +1111,8 @@ struct ext4_inode_info { /* mballoc */ atomic_t i_prealloc_active; - struct list_head i_prealloc_list; - spinlock_t i_prealloc_lock; + struct rb_root i_prealloc_node; + rwlock_t i_prealloc_lock; /* extents status tree */ struct ext4_es_tree i_es_tree; diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index e2078c45898a..f24b959559b8 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -4020,6 +4020,24 @@ static void ext4_mb_normalize_group_request(struct ext4_allocation_context *ac) mb_debug(sb, "goal %u blocks for locality group\n", ac->ac_g_ex.fe_len); } +/* + * This function returns the next element to look at during inode + * PA rbtree walk. We assume that we have held the inode PA rbtree lock + * (ei->i_prealloc_lock) + * + * new_start The start of the range we want to compare + * cur_start The existing start that we are comparing against + * node The node of the rb_tree + */ +static inline struct rb_node* +ext4_mb_pa_rb_next_iter(int new_start, int cur_start, struct rb_node *node) +{ + if (new_start < cur_start) + return node->rb_left; + else + return node->rb_right; +} + static inline void ext4_mb_pa_assert_overlap(struct ext4_allocation_context *ac, ext4_lblk_t start, ext4_lblk_t end) @@ -4028,27 +4046,31 @@ ext4_mb_pa_assert_overlap(struct ext4_allocation_context *ac, struct ext4_inode_info *ei = EXT4_I(ac->ac_inode); struct ext4_prealloc_space *tmp_pa; ext4_lblk_t tmp_pa_start, tmp_pa_end; + struct rb_node *iter; - rcu_read_lock(); - list_for_each_entry_rcu(tmp_pa, &ei->i_prealloc_list, pa_node.inode_list) { - spin_lock(&tmp_pa->pa_lock); - if (tmp_pa->pa_deleted == 0) { - tmp_pa_start = tmp_pa->pa_lstart; - tmp_pa_end = tmp_pa->pa_lstart + EXT4_C2B(sbi, tmp_pa->pa_len); + read_lock(&ei->i_prealloc_lock); + iter = ei->i_prealloc_node.rb_node; + while (iter) { + tmp_pa = rb_entry(iter, struct ext4_prealloc_space, + pa_node.inode_node); + tmp_pa_start = tmp_pa->pa_lstart; + tmp_pa_end = tmp_pa->pa_lstart + EXT4_C2B(sbi, tmp_pa->pa_len); + spin_lock(&tmp_pa->pa_lock); + if (tmp_pa->pa_deleted == 0) BUG_ON(!(start >= tmp_pa_end || end <= tmp_pa_start)); - } spin_unlock(&tmp_pa->pa_lock); + + iter = ext4_mb_pa_rb_next_iter(start, tmp_pa_start, iter); } - rcu_read_unlock(); + read_unlock(&ei->i_prealloc_lock); } - /* * Given an allocation context "ac" and a range "start", "end", check * and adjust boundaries if the range overlaps with any of the existing * preallocatoins stored in the corresponding inode of the allocation context. * - *Parameters: + * Parameters: * ac allocation context * start start of the new range * end end of the new range @@ -4060,6 +4082,7 @@ ext4_mb_pa_adjust_overlap(struct ext4_allocation_context *ac, struct ext4_inode_info *ei = EXT4_I(ac->ac_inode); struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); struct ext4_prealloc_space *tmp_pa; + struct rb_node *iter; ext4_lblk_t new_start, new_end; ext4_lblk_t tmp_pa_start, tmp_pa_end; @@ -4067,19 +4090,29 @@ ext4_mb_pa_adjust_overlap(struct ext4_allocation_context *ac, new_end = *end; /* check we don't cross already preallocated blocks */ - rcu_read_lock(); - list_for_each_entry_rcu(tmp_pa, &ei->i_prealloc_list, pa_node.inode_list) { - if (tmp_pa->pa_deleted) + read_lock(&ei->i_prealloc_lock); + iter = ei->i_prealloc_node.rb_node; + while (iter) { + tmp_pa = rb_entry(iter, struct ext4_prealloc_space, + pa_node.inode_node); + tmp_pa_start = tmp_pa->pa_lstart; + tmp_pa_end = tmp_pa->pa_lstart + EXT4_C2B(sbi, tmp_pa->pa_len); + + /* + * If pa is deleted, ignore overlaps and just iterate in rbtree + * based on tmp_pa_start + */ + if (tmp_pa->pa_deleted) { + iter = ext4_mb_pa_rb_next_iter(new_start, tmp_pa_start, iter); continue; + } spin_lock(&tmp_pa->pa_lock); if (tmp_pa->pa_deleted) { spin_unlock(&tmp_pa->pa_lock); + iter = ext4_mb_pa_rb_next_iter(new_start, tmp_pa_start, iter); continue; } - tmp_pa_start = tmp_pa->pa_lstart; - tmp_pa_end = tmp_pa->pa_lstart + EXT4_C2B(sbi, tmp_pa->pa_len); - /* PA must not overlap original request */ BUG_ON(!(ac->ac_o_ex.fe_logical >= tmp_pa_end || ac->ac_o_ex.fe_logical < tmp_pa_start)); @@ -4087,6 +4120,7 @@ ext4_mb_pa_adjust_overlap(struct ext4_allocation_context *ac, /* skip PAs this normalized request doesn't overlap with */ if (tmp_pa_start >= new_end || tmp_pa_end <= new_start) { spin_unlock(&tmp_pa->pa_lock); + iter = ext4_mb_pa_rb_next_iter(new_start, tmp_pa_start, iter); continue; } BUG_ON(tmp_pa_start <= new_start && tmp_pa_end >= new_end); @@ -4100,8 +4134,9 @@ ext4_mb_pa_adjust_overlap(struct ext4_allocation_context *ac, new_end = tmp_pa_start; } spin_unlock(&tmp_pa->pa_lock); + iter = ext4_mb_pa_rb_next_iter(new_start, tmp_pa_start, iter); } - rcu_read_unlock(); + read_unlock(&ei->i_prealloc_lock); /* XXX: extra loop to check we really don't overlap preallocations */ ext4_mb_pa_assert_overlap(ac, new_start, new_end); @@ -4228,7 +4263,6 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac, ext4_mb_pa_adjust_overlap(ac, &start, &end); size = end - start; - /* * In this function "start" and "size" are normalized for better * alignment and length such that we could preallocate more blocks. @@ -4437,6 +4471,7 @@ ext4_mb_use_preallocated(struct ext4_allocation_context *ac) struct ext4_locality_group *lg; struct ext4_prealloc_space *tmp_pa, *cpa = NULL; ext4_lblk_t tmp_pa_start, tmp_pa_end; + struct rb_node *iter; ext4_fsblk_t goal_block; /* only data can be preallocated */ @@ -4444,17 +4479,23 @@ ext4_mb_use_preallocated(struct ext4_allocation_context *ac) return false; /* first, try per-file preallocation */ - rcu_read_lock(); - list_for_each_entry_rcu(tmp_pa, &ei->i_prealloc_list, pa_node.inode_list) { + read_lock(&ei->i_prealloc_lock); + iter = ei->i_prealloc_node.rb_node; + while (iter) { + tmp_pa = rb_entry(iter, struct ext4_prealloc_space, pa_node.inode_node); /* all fields in this condition don't change, * so we can skip locking for them */ tmp_pa_start = tmp_pa->pa_lstart; tmp_pa_end = tmp_pa->pa_lstart + EXT4_C2B(sbi, tmp_pa->pa_len); + /* original request start doesn't lie in this PA */ if (ac->ac_o_ex.fe_logical < tmp_pa_start || - ac->ac_o_ex.fe_logical >= tmp_pa_end) + ac->ac_o_ex.fe_logical >= tmp_pa_end) { + iter = ext4_mb_pa_rb_next_iter(ac->ac_o_ex.fe_logical, + tmp_pa_start, iter); continue; + } /* non-extent files can't have physical blocks past 2^32 */ if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)) && @@ -4474,12 +4515,14 @@ ext4_mb_use_preallocated(struct ext4_allocation_context *ac) ext4_mb_use_inode_pa(ac, tmp_pa); spin_unlock(&tmp_pa->pa_lock); ac->ac_criteria = 10; - rcu_read_unlock(); + read_unlock(&ei->i_prealloc_lock); return true; } spin_unlock(&tmp_pa->pa_lock); + iter = ext4_mb_pa_rb_next_iter(ac->ac_o_ex.fe_logical, + tmp_pa_start, iter); } - rcu_read_unlock(); + read_unlock(&ei->i_prealloc_lock); /* can we use group allocation? */ if (!(ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)) @@ -4631,6 +4674,7 @@ static void ext4_mb_put_pa(struct ext4_allocation_context *ac, { ext4_group_t grp; ext4_fsblk_t grp_blk; + struct ext4_inode_info *ei = EXT4_I(ac->ac_inode); /* in this short window concurrent discard can set pa_deleted */ spin_lock(&pa->pa_lock); @@ -4676,16 +4720,34 @@ static void ext4_mb_put_pa(struct ext4_allocation_context *ac, ext4_unlock_group(sb, grp); if (pa->pa_type == MB_INODE_PA) { - spin_lock(pa->pa_node_lock.inode_lock); - list_del_rcu(&pa->pa_node.inode_list); - spin_unlock(pa->pa_node_lock.inode_lock); + write_lock(pa->pa_node_lock.inode_lock); + rb_erase(&pa->pa_node.inode_node, &ei->i_prealloc_node); + write_unlock(pa->pa_node_lock.inode_lock); + ext4_mb_pa_free(pa); } else { spin_lock(pa->pa_node_lock.lg_lock); list_del_rcu(&pa->pa_node.lg_list); spin_unlock(pa->pa_node_lock.lg_lock); + call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback); } +} + +static int ext4_mb_pa_cmp(struct rb_node *new, struct rb_node *cur) +{ + ext4_grpblk_t cur_start, new_start; + struct ext4_prealloc_space *cur_pa = rb_entry(cur, + struct ext4_prealloc_space, + pa_node.inode_node); + struct ext4_prealloc_space *new_pa = rb_entry(new, + struct ext4_prealloc_space, + pa_node.inode_node); + cur_start = cur_pa->pa_lstart; + new_start = new_pa->pa_lstart; - call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback); + if (new_start < cur_start) + return 1; + else + return -1; } /* @@ -4751,7 +4813,6 @@ ext4_mb_new_inode_pa(struct ext4_allocation_context *ac) pa->pa_len = ac->ac_b_ex.fe_len; pa->pa_free = pa->pa_len; spin_lock_init(&pa->pa_lock); - INIT_LIST_HEAD(&pa->pa_node.inode_list); INIT_LIST_HEAD(&pa->pa_group_list); pa->pa_deleted = 0; pa->pa_type = MB_INODE_PA; @@ -4771,9 +4832,10 @@ ext4_mb_new_inode_pa(struct ext4_allocation_context *ac) list_add(&pa->pa_group_list, &grp->bb_prealloc_list); - spin_lock(pa->pa_node_lock.inode_lock); - list_add_rcu(&pa->pa_node.inode_list, &ei->i_prealloc_list); - spin_unlock(pa->pa_node_lock.inode_lock); + write_lock(pa->pa_node_lock.inode_lock); + ext4_mb_rb_insert(&ei->i_prealloc_node, &pa->pa_node.inode_node, + ext4_mb_pa_cmp); + write_unlock(pa->pa_node_lock.inode_lock); atomic_inc(&ei->i_prealloc_active); } @@ -4939,6 +5001,7 @@ ext4_mb_discard_group_preallocations(struct super_block *sb, struct ext4_prealloc_space *pa, *tmp; struct list_head list; struct ext4_buddy e4b; + struct ext4_inode_info *ei; int err; int free = 0; @@ -5002,18 +5065,21 @@ ext4_mb_discard_group_preallocations(struct super_block *sb, list_del_rcu(&pa->pa_node.lg_list); spin_unlock(pa->pa_node_lock.lg_lock); } else { - spin_lock(pa->pa_node_lock.inode_lock); - list_del_rcu(&pa->pa_node.inode_list); - spin_unlock(pa->pa_node_lock.inode_lock); + write_lock(pa->pa_node_lock.inode_lock); + ei = EXT4_I(pa->pa_inode); + rb_erase(&pa->pa_node.inode_node, &ei->i_prealloc_node); + write_unlock(pa->pa_node_lock.inode_lock); } - if (pa->pa_type == MB_GROUP_PA) + list_del(&pa->u.pa_tmp_list); + + if (pa->pa_type == MB_GROUP_PA) { ext4_mb_release_group_pa(&e4b, pa); - else + call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback); + } else { ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa); - - list_del(&pa->u.pa_tmp_list); - call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback); + ext4_mb_pa_free(pa); + } } ext4_unlock_group(sb, group); @@ -5043,6 +5109,7 @@ void ext4_discard_preallocations(struct inode *inode, unsigned int needed) ext4_group_t group = 0; struct list_head list; struct ext4_buddy e4b; + struct rb_node *iter; int err; if (!S_ISREG(inode->i_mode)) { @@ -5065,17 +5132,18 @@ void ext4_discard_preallocations(struct inode *inode, unsigned int needed) repeat: /* first, collect all pa's in the inode */ - spin_lock(&ei->i_prealloc_lock); - while (!list_empty(&ei->i_prealloc_list) && needed) { - pa = list_entry(ei->i_prealloc_list.prev, - struct ext4_prealloc_space, pa_node.inode_list); + write_lock(&ei->i_prealloc_lock); + for (iter = rb_first(&ei->i_prealloc_node); iter && needed; iter = rb_next(iter)) { + pa = rb_entry(iter, struct ext4_prealloc_space, + pa_node.inode_node); BUG_ON(pa->pa_node_lock.inode_lock != &ei->i_prealloc_lock); + spin_lock(&pa->pa_lock); if (atomic_read(&pa->pa_count)) { /* this shouldn't happen often - nobody should * use preallocation while we're discarding it */ spin_unlock(&pa->pa_lock); - spin_unlock(&ei->i_prealloc_lock); + write_unlock(&ei->i_prealloc_lock); ext4_msg(sb, KERN_ERR, "uh-oh! used pa while discarding"); WARN_ON(1); @@ -5086,7 +5154,7 @@ void ext4_discard_preallocations(struct inode *inode, unsigned int needed) if (pa->pa_deleted == 0) { ext4_mb_mark_pa_deleted(sb, pa); spin_unlock(&pa->pa_lock); - list_del_rcu(&pa->pa_node.inode_list); + rb_erase(&pa->pa_node.inode_node, &ei->i_prealloc_node); list_add(&pa->u.pa_tmp_list, &list); needed--; continue; @@ -5094,7 +5162,7 @@ void ext4_discard_preallocations(struct inode *inode, unsigned int needed) /* someone is deleting pa right now */ spin_unlock(&pa->pa_lock); - spin_unlock(&ei->i_prealloc_lock); + write_unlock(&ei->i_prealloc_lock); /* we have to wait here because pa_deleted * doesn't mean pa is already unlinked from @@ -5111,7 +5179,7 @@ void ext4_discard_preallocations(struct inode *inode, unsigned int needed) schedule_timeout_uninterruptible(HZ); goto repeat; } - spin_unlock(&ei->i_prealloc_lock); + write_unlock(&ei->i_prealloc_lock); list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) { BUG_ON(pa->pa_type != MB_INODE_PA); @@ -5143,7 +5211,7 @@ void ext4_discard_preallocations(struct inode *inode, unsigned int needed) put_bh(bitmap_bh); list_del(&pa->u.pa_tmp_list); - call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback); + ext4_mb_pa_free(pa); } } @@ -5516,7 +5584,6 @@ static void ext4_mb_trim_inode_pa(struct inode *inode) static int ext4_mb_release_context(struct ext4_allocation_context *ac) { struct inode *inode = ac->ac_inode; - struct ext4_inode_info *ei = EXT4_I(inode); struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); struct ext4_prealloc_space *pa = ac->ac_pa; if (pa) { @@ -5543,16 +5610,6 @@ static int ext4_mb_release_context(struct ext4_allocation_context *ac) } } - if (pa->pa_type == MB_INODE_PA) { - /* - * treat per-inode prealloc list as a lru list, then try - * to trim the least recently used PA. - */ - spin_lock(pa->pa_node_lock.inode_lock); - list_move(&pa->pa_node.inode_list, &ei->i_prealloc_list); - spin_unlock(pa->pa_node_lock.inode_lock); - } - ext4_mb_put_pa(ac, ac->ac_sb, pa); } if (ac->ac_bitmap_page) diff --git a/fs/ext4/mballoc.h b/fs/ext4/mballoc.h index c5fc6eec19a3..2c32e9d1a22c 100644 --- a/fs/ext4/mballoc.h +++ b/fs/ext4/mballoc.h @@ -115,7 +115,7 @@ struct ext4_free_data { struct ext4_prealloc_space { union { - struct list_head inode_list; /* for inode PAs */ + struct rb_node inode_node; /* for inode PA rbtree */ struct list_head lg_list; /* for lg PAs */ } pa_node; struct list_head pa_group_list; @@ -132,10 +132,10 @@ struct ext4_prealloc_space { ext4_grpblk_t pa_free; /* how many blocks are free */ unsigned short pa_type; /* pa type. inode or group */ union { - spinlock_t *inode_lock; /* locks the inode list holding this PA */ + rwlock_t *inode_lock; /* locks the rbtree holding this PA */ spinlock_t *lg_lock; /* locks the lg list holding this PA */ } pa_node_lock; - struct inode *pa_inode; /* hack, for history only */ + struct inode *pa_inode; /* used to get the inode during group discard */ }; enum { diff --git a/fs/ext4/super.c b/fs/ext4/super.c index a6d71a41a0c4..e18ad191a6de 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -1330,9 +1330,9 @@ static struct inode *ext4_alloc_inode(struct super_block *sb) inode_set_iversion(&ei->vfs_inode, 1); spin_lock_init(&ei->i_raw_lock); - INIT_LIST_HEAD(&ei->i_prealloc_list); + ei->i_prealloc_node = RB_ROOT; atomic_set(&ei->i_prealloc_active, 0); - spin_lock_init(&ei->i_prealloc_lock); + rwlock_init(&ei->i_prealloc_lock); ext4_es_init_tree(&ei->i_es_tree); rwlock_init(&ei->i_es_lock); INIT_LIST_HEAD(&ei->i_es_list);