From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2309A18DF6B for ; Wed, 20 Nov 2024 10:03:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732097037; cv=none; b=j5Kg+gtjGeQQj/2FkPhMtJf9JEgTmRB4bpHDc17cXrm3heBtyZG5ap1RldKZwszw7nyrW0CO/uhbmVyQyzU6hRC9Pzgk07fo7Y4T90yeM6GWnVfDlLikAnDMbNiSmmrSfHKHBNFbzooLY8IrOyz8hbkuM2zxJaPHSyZtdRKhhyw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732097037; c=relaxed/simple; bh=NCL+xFcAGDzVgzKqPFZ6LNmSw/lXx93z3rS31sAxiRQ=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=TSvqAN6yn6JfWusaEMIP4+bEtms3FpOwTnoQ0oH6G6ctUF8agZZJfyCB0LgnMs213I26Cgz7Gymnwwdh8+LUyKhLdzrxJ2/zpSOyiOswUN9vYLOl4CyS14vW9gSH2j+HLk3uw8X8VRsDHkiwxLtOT4kdgDCw5RpsdsmJkn8mSPw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HWl8xoPv; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="HWl8xoPv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 70CB2C4CECD; Wed, 20 Nov 2024 10:03:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1732097036; bh=NCL+xFcAGDzVgzKqPFZ6LNmSw/lXx93z3rS31sAxiRQ=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=HWl8xoPvZihVH2vh772nNYGbTOR1FXOaSojv/4xviBZPTvcZI4ldTfjwYJxEMQ1z4 R1lHvUIyIm6XzMk3dd0nO71luU26EaLlpp1dypOz4WOd+iittp5t0q/aUB4KFppkR5 0SVNl8ImnNRtC9zWSuJglcm3CAXTJAX/SVMxM9313ri5kh/h3ETXIKAr7JdTxEiC3r J+mhZ0oRSBbWLAMVT6x7FkKIlAsMOZcLK7Uqv1+Ua9RNAtKpiggA8t0s/K+M/OE57q gmAuJI+cyJ92ByiFH+YQ9CjnaeEdhqkmbnsm27qqsw5GUWq6xXMb72oklFCyMBQ5+L pKHQnjm2H3IFA== Message-ID: <5925e2c0-e85f-4e83-a41a-594d954814a1@kernel.org> Date: Wed, 20 Nov 2024 18:03:52 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: Chao Yu , Xiuhong Wang , Xiuhong Wang , jaegeuk@kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, hao_hao.wang@unisoc.com, ke.wang@unisoc.com Subject: Re: [PATCH] f2fs: Fix to avoid long time to shrink extent cache To: Zhiguo Niu References: <20241112110627.1314632-1-xiuhong.wang@unisoc.com> <5b0c17da-f1e1-490d-a560-3312bc8c3247@kernel.org> <65b89566-1038-4422-9e2e-4d7da26dd1c7@kernel.org> <5b40ca3c-efd6-4b50-8d11-845930a0e365@kernel.org> Content-Language: en-US From: Chao Yu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 2024/11/20 17:19, Zhiguo Niu wrote: > Chao Yu 于2024年11月20日周三 16:15写道： >> >> On 2024/11/20 13:45, Zhiguo Niu wrote: >>> Chao Yu 于2024年11月20日周三 11:26写道： >>>> >>>> On 2024/11/19 16:26, Zhiguo Niu wrote: >>>>> Chao Yu 于2024年11月19日周二 15:50写道： >>>>>> >>>>>> On 2024/11/19 14:46, Xiuhong Wang wrote: >>>>>>> Chao Yu 于2024年11月19日周二 14:05写道： >>>>>>>> >>>>>>>> On 2024/11/12 19:06, Xiuhong Wang wrote: >>>>>>>>> We encountered a system hang problem based on the following >>>>>>>>> experiment: >>>>>>>>> There are 17 processes, 8 of which do 4k data read, write and >>>>>>>>> compare tests, and 8 do 64k read, write and compare tests. Each >>>>>>>>> thread writes a 256M file, and another thread writes a large file >>>>>>>>> to 80% of the disk, and then keeps doing read operations, all of >>>>>>>>> which are direct operations. This will cause the large file to be >>>>>>>>> filled to 80% of the disk to be severely fragmented. On a 512GB >>>>>>>>> device, this large file may generate a huge zombie extent tree. >>>>>>>>> >>>>>>>>> When system shutting down, the init process needs to wait for the >>>>>>>>> writeback process, and the writeback process may encounter the >>>>>>>>> situation where the READ_EXTENT_CACHE space is insufficient and >>>>>>>>> needs to free the zombie extent tree. The extent tree has a large >>>>>>>>> number of extent nodes, it will a long free time to free, which >>>>>>>>> triggers system hang. >>>>>>>> > > The stack when the problem occurs is as follows: >>>>>>>>> crash_arm64> bt 1 >>>>>>>>> PID: 1 TASK: ffffff80801a9200 CPU: 1 COMMAND: "init" >>>>>>>>> #0 [ffffffc00806b9a0] __switch_to at ffffffc00810711c >>>>>>>>> #1 [ffffffc00806ba00] __schedule at ffffffc0097c1c4c >>>>>>>>> #2 [ffffffc00806ba60] schedule at ffffffc0097c2308 >>>>>>>>> #3 [ffffffc00806bab0] wb_wait_for_completion at ffffffc0086320d4 >>>>>>>>> #4 [ffffffc00806bb20] writeback_inodes_sb at ffffffc00863719c >>>>>>>>> #5 [ffffffc00806bba0] sync_filesystem at ffffffc00863c98c >>>>>>>>> #6 [ffffffc00806bbc0] f2fs_quota_off_umount at ffffffc00886fc60 >>>>>>>>> #7 [ffffffc00806bc20] f2fs_put_super at ffffffc0088715b4 >>>>>>>>> #8 [ffffffc00806bc60] generic_shutdown_super at ffffffc0085cd61c >>>>>>>>> #9 [ffffffc00806bcd0] kill_f2fs_super at ffffffc00886b3dc >>>>>>>>> >>>>>>>>> crash_arm64> bt 14997 >>>>>>>>> PID: 14997 TASK: ffffff8119d82400 CPU: 3 COMMAND: "kworker/u16:0" >>>>>>>>> #0 [ffffffc019f8b760] __detach_extent_node at ffffffc0088d5a58 >>>>>>>>> #1 [ffffffc019f8b790] __release_extent_node at ffffffc0088d5970 >>>>>>>>> #2 [ffffffc019f8b810] f2fs_shrink_extent_tree at ffffffc0088d5c7c >>>>>>>>> #3 [ffffffc019f8b8a0] f2fs_balance_fs_bg at ffffffc0088c109c >>>>>>>>> #4 [ffffffc019f8b910] f2fs_write_node_pages at ffffffc0088bd4d8 >>>>>>>>> #5 [ffffffc019f8b990] do_writepages at ffffffc0084a0b5c >>>>>>>>> #6 [ffffffc019f8b9f0] __writeback_single_inode at ffffffc00862ee28 >>>>>>>>> #7 [ffffffc019f8bb30] writeback_sb_inodes at ffffffc0086358c0 >>>>>>>>> #8 [ffffffc019f8bc10] wb_writeback at ffffffc0086362dc >>>>>>>>> #9 [ffffffc019f8bcc0] wb_do_writeback at ffffffc008634910 >>>>>>>>> >>>>>>>>> Process 14997 ran for too long and caused the system hang. >>>>>>>>> >>>>>>>>> At this time, there are still 1086911 extent nodes in this zombie >>>>>>>>> extent tree that need to be cleaned up. >>>>>>>>> >>>>>>>>> crash_arm64_sprd_v8.0.3++> extent_tree.node_cnt ffffff80896cc500 >>>>>>>>> node_cnt = { >>>>>>>>> counter = 1086911 >>>>>>>>> }, >>>>>>>>> >>>>>>>>> The root cause of this problem is that when the f2fs_balance_fs >>>>>>>>> function is called in the write process, it will determine >>>>>>>>> whether to call f2fs_balance_fs_bg, but it is difficult to >>>>>>>>> meet the condition of excess_cached_nats. When the >>>>>>>>> f2fs_shrink_extent_tree function is called to free during >>>>>>>>> f2fs_write_node_pages, there are too many extent nodes on the >>>>>>>>> extent tree, which causes a loop and causes a system hang. >>>>>>>>> >>>>>>>>> To solve this problem, when calling f2fs_balance_fs, check whether >>>>>>>>> the extent cache is sufficient. If not, release the zombie extent >>>>>>>>> tree. >>>>>>>>> >>>>>>>>> Signed-off-by: Xiuhong Wang >>>>>>>>> Signed-off-by: Zhiguo Niu >>>>>>>>> --- >>>>>>>>> Test the problem with the temporary versions: >>>>>>>>> patch did not reproduce the problem, the patch is as follows: >>>>>>>>> @@ -415,7 +415,7 @@ void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need) >>>>>>>>> f2fs_stop_checkpoint(sbi, false, STOP_CP_REASON_FAULT_INJECT); >>>>>>>>> >>>>>>>>> /* balance_fs_bg is able to be pending */ >>>>>>>>> - if (need && excess_cached_nats(sbi)) >>>>>>>>> + if (need) >>>>>>>>> f2fs_balance_fs_bg(sbi, false); >>>>>>>>> >>>>>>>>> --- >>>>>>>>> fs/f2fs/segment.c | 4 +++- >>>>>>>>> 1 file changed, 3 insertions(+), 1 deletion(-) >>>>>>>>> >>>>>>>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c >>>>>>>>> index 1766254279d2..390bec177567 100644 >>>>>>>>> --- a/fs/f2fs/segment.c >>>>>>>>> +++ b/fs/f2fs/segment.c >>>>>>>>> @@ -415,7 +415,9 @@ void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need) >>>>>>>>> f2fs_stop_checkpoint(sbi, false, STOP_CP_REASON_FAULT_INJECT); >>>>>>>>> >>>>>>>>> /* balance_fs_bg is able to be pending */ >>>>>>>>> - if (need && excess_cached_nats(sbi)) >>>>>>>>> + if (need && (excess_cached_nats(sbi) || >>>>>>>>> + !f2fs_available_free_memory(sbi, READ_EXTENT_CACHE) || >>>>>>>>> + !f2fs_available_free_memory(sbi, AGE_EXTENT_CACHE))) >>>>>>>> >>>>>>>> Hi, >>>>>>>> >>>>>>>> I doubt if there is no enough memory, we may still run into >>>>>>>> f2fs_shrink_extent_tree() and suffer such long time delay. >>>>>>>> >>>>>>>> So, can we just let __free_extent_tree() break the loop once we have >>>>>>>> released entries w/ target number? something like this: >>>>>>>> >>>>>>>> --- >>>>>>>> fs/f2fs/extent_cache.c | 15 ++++++++++----- >>>>>>>> 1 file changed, 10 insertions(+), 5 deletions(-) >>>>>>>> >>>>>>>> diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c >>>>>>>> index 019c1f7b7fa5..38c71c1c4fb7 100644 >>>>>>>> --- a/fs/f2fs/extent_cache.c >>>>>>>> +++ b/fs/f2fs/extent_cache.c >>>>>>>> @@ -379,11 +379,12 @@ static struct extent_tree *__grab_extent_tree(struct inode *inode, >>>>>>>> } >>>>>>>> >>>>>>>> static unsigned int __free_extent_tree(struct f2fs_sb_info *sbi, >>>>>>>> - struct extent_tree *et) >>>>>>>> + struct extent_tree *et, unsigned int nr_shrink) >>>>>>>> { >>>>>>>> struct rb_node *node, *next; >>>>>>>> struct extent_node *en; >>>>>>>> unsigned int count = atomic_read(&et->node_cnt); >>>>>>>> + unsigned int i = 0; >>>>>>>> >>>>>>>> node = rb_first_cached(&et->root); >>>>>>>> while (node) { >>>>>>>> @@ -391,6 +392,9 @@ static unsigned int __free_extent_tree(struct f2fs_sb_info *sbi, >>>>>>>> en = rb_entry(node, struct extent_node, rb_node); >>>>>>>> __release_extent_node(sbi, et, en); >>>>>>>> node = next; >>>>>>>> + >>>>>>>> + if (nr_shrink && ++i >= nr_shrink) >>>>>>>> + break; >>>>>>>> } >>>>>>>> >>>>>>>> return count - atomic_read(&et->node_cnt); >>>>>>>> @@ -761,7 +765,7 @@ static void __update_extent_tree_range(struct inode *inode, >>>>>>>> } >>>>>>>> >>>>>>>> if (is_inode_flag_set(inode, FI_NO_EXTENT)) >>>>>>>> - __free_extent_tree(sbi, et); >>>>>>>> + __free_extent_tree(sbi, et, 0); >>>>>>>> >>>>>>>> if (et->largest_updated) { >>>>>>>> et->largest_updated = false; >>>>>>>> @@ -942,7 +946,8 @@ static unsigned int __shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink >>>>>>>> list_for_each_entry_safe(et, next, &eti->zombie_list, list) { >>>>>>>> if (atomic_read(&et->node_cnt)) { >>>>>>>> write_lock(&et->lock); >>>>>>>> - node_cnt += __free_extent_tree(sbi, et); >>>>>>>> + node_cnt += __free_extent_tree(sbi, et, >>>>>>>> + nr_shrink - node_cnt - tree_cnt); >>>>>>>> write_unlock(&et->lock); >>>>>>>> } >>>>>>>> f2fs_bug_on(sbi, atomic_read(&et->node_cnt)); >>>>>>>> @@ -1095,7 +1100,7 @@ static unsigned int __destroy_extent_node(struct inode *inode, >>>>>>>> return 0; >>>>>>>> >>>>>>>> write_lock(&et->lock); >>>>>>>> - node_cnt = __free_extent_tree(sbi, et); >>>>>>>> + node_cnt = __free_extent_tree(sbi, et, 0); >>>>>>>> write_unlock(&et->lock); >>>>>>>> >>>>>>>> return node_cnt; >>>>>>>> @@ -1117,7 +1122,7 @@ static void __drop_extent_tree(struct inode *inode, enum extent_type type) >>>>>>>> return; >>>>>>>> >>>>>>>> write_lock(&et->lock); >>>>>>>> - __free_extent_tree(sbi, et); >>>>>>>> + __free_extent_tree(sbi, et, 0); >>>>>>>> if (type == EX_READ) { >>>>>>>> set_inode_flag(inode, FI_NO_EXTENT); >>>>>>>> if (et->largest.len) { >>>>>>>> -- >>>>>>>> 2.40.1 >>>>>>>> >>>>>>>> Thanks, >>>>>>>> >>>>>>>>> f2fs_balance_fs_bg(sbi, false); >>>>>>>>> >>>>>>>>> if (!f2fs_is_checkpoint_ready(sbi)) >>>>>>>> >>>>>>> >>>>>>> >>>>>>> Hi chao, >>>>>>> >>>>>>> We have also considered this approach, but the problem still occurs >>>>>>> after retesting. >>>>>>> 1. The problem still occurs in the following call of the unmount data process. >>>>>>> f2fs_put_super -> f2fs_leave_shrinker >>>>>> >>>>>> Yes, I guess we need to fix this path as well, however, your patch didn't >>>>>> cover this path as well, am I missing something? >>>>> Dear Chao, >>>>> This patch version aim to shrink extent cache as early as possible on >>>>> the "all write path" >>>>> by "write action" -> f2fs_balance_fs -> f2fs_balance_fs_bg >>>> >>>> Zhiguo, thanks for explaining again. >>>> >>> Dear Chao, >>>> However, I doubt covering all write paths is not enough, because extent >>>> node can increase when f2fs_precache_extents() was called from paths >>>> including fadvise/fiemap/swapon/ioc_precache_extents, and there may be >>>> no writeback, so we may get no chance to call into f2fs_balance_fs_bg(), >>>> e.g. there is no data update in mountpoint, or mountpoint is readonly. >>> yes, Indeed it is. >>>> >>>>> As the comment , the "excess_cached_nats" is difficult to achieve in >>>>> this scenario, and >>>> >>>> Another concern is, in high-end products w/ more memory, it may has less >>>> chance to hit newly added condition in f2fs_balance_fs()? not sure though. >>> I also agree with this. >>> There is no other better idea for me(^^) excpetion for the two methods >>> we discussed above. >>> any good suggestions ? ^^ >> > Dear Chao, > It is good solution to limit the maximum extent count of each inode. >> What do you think of this? >> >> From 8646c28027d5b050938335066ab56abbeca799e7 Mon Sep 17 00:00:00 2001 >> From: Chao Yu >> Date: Tue, 19 Nov 2024 11:53:09 +0800 >> Subject: [PATCH 1/2] f2fs: fix to shrink read extent node in batches >> >> Signed-off-by: Chao Yu >> --- >> fs/f2fs/extent_cache.c | 64 ++++++++++++++++++++++++------------------ >> 1 file changed, 37 insertions(+), 27 deletions(-) >> >> diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c >> index 019c1f7b7fa5..0c0d05f8551a 100644 >> --- a/fs/f2fs/extent_cache.c >> +++ b/fs/f2fs/extent_cache.c >> @@ -379,21 +379,22 @@ static struct extent_tree *__grab_extent_tree(struct inode *inode, >> } >> >> static unsigned int __free_extent_tree(struct f2fs_sb_info *sbi, >> - struct extent_tree *et) >> + struct extent_tree *et, unsigned int nr_shrink) >> { >> struct rb_node *node, *next; >> struct extent_node *en; >> - unsigned int count = atomic_read(&et->node_cnt); >> + unsigned int count; >> >> node = rb_first_cached(&et->root); >> - while (node) { >> + >> + for (count = 0; node && count < nr_shrink; count++) { >> next = rb_next(node); >> en = rb_entry(node, struct extent_node, rb_node); >> __release_extent_node(sbi, et, en); >> node = next; >> } >> >> - return count - atomic_read(&et->node_cnt); >> + return count; >> } >> >> static void __drop_largest_extent(struct extent_tree *et, >> @@ -622,6 +623,30 @@ static struct extent_node *__insert_extent_tree(struct f2fs_sb_info *sbi, >> return en; >> } >> >> +static unsigned int __destroy_extent_node(struct inode *inode, >> + enum extent_type type) >> +{ >> + struct f2fs_sb_info *sbi = F2FS_I_SB(inode); >> + struct extent_tree *et = F2FS_I(inode)->extent_tree[type]; >> + unsigned int nr_shrink = type == EX_READ ? >> + READ_EXTENT_CACHE_SHRINK_NUMBER : >> + AGE_EXTENT_CACHE_SHRINK_NUMBER; >> + unsigned int node_cnt = 0; >> + >> + if (!et || !atomic_read(&et->node_cnt)) >> + return 0; >> + >> + while (atomic_read(&et->node_cnt)) { >> + write_lock(&et->lock); >> + node_cnt = __free_extent_tree(sbi, et, nr_shrink); > should be: node_cnt += __free_extent_tree(sbi, et, nr_shrink); ?? Correct, >> + write_unlock(&et->lock); >> + } >> + >> + f2fs_bug_on(sbi, atomic_read(&et->node_cnt)); >> + >> + return node_cnt; >> +} >> + >> static void __update_extent_tree_range(struct inode *inode, >> struct extent_info *tei, enum extent_type type) >> { >> @@ -760,9 +785,6 @@ static void __update_extent_tree_range(struct inode *inode, >> } >> } >> >> - if (is_inode_flag_set(inode, FI_NO_EXTENT)) >> - __free_extent_tree(sbi, et); >> - >> if (et->largest_updated) { >> et->largest_updated = false; >> updated = true; >> @@ -780,6 +802,9 @@ static void __update_extent_tree_range(struct inode *inode, >> out_read_extent_cache: >> write_unlock(&et->lock); >> >> + if (is_inode_flag_set(inode, FI_NO_EXTENT)) >> + __destroy_extent_node(inode, EX_READ); >> + >> if (updated) >> f2fs_mark_inode_dirty_sync(inode, true); >> } >> @@ -942,7 +967,8 @@ static unsigned int __shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink >> list_for_each_entry_safe(et, next, &eti->zombie_list, list) { >> if (atomic_read(&et->node_cnt)) { >> write_lock(&et->lock); >> - node_cnt += __free_extent_tree(sbi, et); >> + node_cnt += __free_extent_tree(sbi, et, >> + nr_shrink - node_cnt - tree_cnt); >> write_unlock(&et->lock); >> } >> f2fs_bug_on(sbi, atomic_read(&et->node_cnt)); > this f2fs_bug_on statment should be removed or omited? > and the following free tree action can not be do if > atomic_read(&et->node_cnt) !=0 ? Yes, will fix this soon, and let me test for a while. Thanks, > thanks! >> @@ -1084,23 +1110,6 @@ unsigned int f2fs_shrink_age_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink >> return __shrink_extent_tree(sbi, nr_shrink, EX_BLOCK_AGE); >> } >> >> -static unsigned int __destroy_extent_node(struct inode *inode, >> - enum extent_type type) >> -{ >> - struct f2fs_sb_info *sbi = F2FS_I_SB(inode); >> - struct extent_tree *et = F2FS_I(inode)->extent_tree[type]; >> - unsigned int node_cnt = 0; >> - >> - if (!et || !atomic_read(&et->node_cnt)) >> - return 0; >> - >> - write_lock(&et->lock); >> - node_cnt = __free_extent_tree(sbi, et); >> - write_unlock(&et->lock); >> - >> - return node_cnt; >> -} >> - >> void f2fs_destroy_extent_node(struct inode *inode) >> { >> __destroy_extent_node(inode, EX_READ); >> @@ -1109,7 +1118,6 @@ void f2fs_destroy_extent_node(struct inode *inode) >> >> static void __drop_extent_tree(struct inode *inode, enum extent_type type) >> { >> - struct f2fs_sb_info *sbi = F2FS_I_SB(inode); >> struct extent_tree *et = F2FS_I(inode)->extent_tree[type]; >> bool updated = false; >> >> @@ -1117,7 +1125,6 @@ static void __drop_extent_tree(struct inode *inode, enum extent_type type) >> return; >> >> write_lock(&et->lock); >> - __free_extent_tree(sbi, et); >> if (type == EX_READ) { >> set_inode_flag(inode, FI_NO_EXTENT); >> if (et->largest.len) { >> @@ -1126,6 +1133,9 @@ static void __drop_extent_tree(struct inode *inode, enum extent_type type) >> } >> } >> write_unlock(&et->lock); >> + >> + __destroy_extent_node(inode, type); >> + >> if (updated) >> f2fs_mark_inode_dirty_sync(inode, true); >> } >> -- >> 2.40.1 >> >> From 3a1b7ec606d6211b2eaf72d148ebe52d38a0bf59 Mon Sep 17 00:00:00 2001 >> From: Chao Yu >> Date: Wed, 20 Nov 2024 15:37:22 +0800 >> Subject: [PATCH 2/2] f2fs: add a sysfs node to limit max read extent count >> per-inode >> >> Signed-off-by: Chao Yu >> --- >> Documentation/ABI/testing/sysfs-fs-f2fs | 6 ++++++ >> fs/f2fs/extent_cache.c | 5 ++++- >> fs/f2fs/f2fs.h | 4 ++++ >> fs/f2fs/sysfs.c | 7 +++++++ >> 4 files changed, 21 insertions(+), 1 deletion(-) >> >> diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs >> index 513296bb6f29..3e1630c70d8a 100644 >> --- a/Documentation/ABI/testing/sysfs-fs-f2fs >> +++ b/Documentation/ABI/testing/sysfs-fs-f2fs >> @@ -822,3 +822,9 @@ Description: It controls the valid block ratio threshold not to trigger excessiv >> for zoned deivces. The initial value of it is 95(%). F2FS will stop the >> background GC thread from intiating GC for sections having valid blocks >> exceeding the ratio. >> + >> +What: /sys/fs/f2fs//max_read_extent_count >> +Date: November 2024 >> +Contact: "Chao Yu" >> +Description: It controls max read extent count for per-inode, the value of threshold >> + is 10240 by default. >> diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c >> index 0c0d05f8551a..b08563ad010d 100644 >> --- a/fs/f2fs/extent_cache.c >> +++ b/fs/f2fs/extent_cache.c >> @@ -717,7 +717,9 @@ static void __update_extent_tree_range(struct inode *inode, >> } >> >> if (end < org_end && (type != EX_READ || >> - org_end - end >= F2FS_MIN_EXTENT_LEN)) { >> + (org_end - end >= F2FS_MIN_EXTENT_LEN && >> + atomic_read(&et->node_cnt) < >> + sbi->max_read_extent_count))) { >> if (parts) { >> __set_extent_info(&ei, >> end, org_end - end, >> @@ -1209,6 +1211,7 @@ void f2fs_init_extent_cache_info(struct f2fs_sb_info *sbi) >> sbi->hot_data_age_threshold = DEF_HOT_DATA_AGE_THRESHOLD; >> sbi->warm_data_age_threshold = DEF_WARM_DATA_AGE_THRESHOLD; >> sbi->last_age_weight = LAST_AGE_WEIGHT; >> + sbi->max_read_extent_count = DEF_MAX_READ_EXTENT_COUNT; >> } >> >> int __init f2fs_create_extent_cache(void) >> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h >> index b65b023a588a..6f2cbf4c5740 100644 >> --- a/fs/f2fs/f2fs.h >> +++ b/fs/f2fs/f2fs.h >> @@ -635,6 +635,9 @@ enum { >> #define DEF_HOT_DATA_AGE_THRESHOLD 262144 >> #define DEF_WARM_DATA_AGE_THRESHOLD 2621440 >> >> +/* default max read extent count per inode */ >> +#define DEF_MAX_READ_EXTENT_COUNT 10240 >> + >> /* extent cache type */ >> enum extent_type { >> EX_READ, >> @@ -1619,6 +1622,7 @@ struct f2fs_sb_info { >> /* for extent tree cache */ >> struct extent_tree_info extent_tree[NR_EXTENT_CACHES]; >> atomic64_t allocated_data_blocks; /* for block age extent_cache */ >> + unsigned int max_read_extent_count; /* max read extent count per inode */ >> >> /* The threshold used for hot and warm data seperation*/ >> unsigned int hot_data_age_threshold; >> diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c >> index bdbf24db667b..d1356c656cac 100644 >> --- a/fs/f2fs/sysfs.c >> +++ b/fs/f2fs/sysfs.c >> @@ -787,6 +787,13 @@ static ssize_t __sbi_store(struct f2fs_attr *a, >> return count; >> } >> >> + if (!strcmp(a->attr.name, "max_read_extent_count")) { >> + if (t > UINT_MAX) >> + return -EINVAL; >> + *ui = (unsigned int)t; >> + return count; >> + } >> + >> if (!strcmp(a->attr.name, "ipu_policy")) { >> if (t >= BIT(F2FS_IPU_MAX)) >> return -EINVAL; >> -- >> 2.40.1 >> >> >> >>> thanks！ >>>> >>>> + if (need && (excess_cached_nats(sbi) || >>>> + !f2fs_available_free_memory(sbi, READ_EXTENT_CACHE) || >>>> + !f2fs_available_free_memory(sbi, AGE_EXTENT_CACHE))) >>>> >>>> I mean will f2fs_available_free_memory(sbi, {READ,AGE}_EXTENT_CACHE) >>>> return true if available memory is sufficient? >>>> >>>> Thanks, >>>> >>>>> trigger the issue in path f2fs_write_node_pages->f2fs_balance_fs_bg(is >>>>> called directly here). >>>>> At that time, there were already a lot of extent node cnt. >>>>> Thanks! >>>>>> >>>>>>> 2. Writing back the inode in the normal write-back process will >>>>>>> release the extent cache, and the problem still occurs. The stack is >>>>>>> as follows: >>>>>> >>>>>> Ditto, >>>>>> >>>>>> Thanks, >>>>>> >>>>>>> [H 103098.974356] c2 [] (rb_erase+0x204/0x334) >>>>>>> [H 103098.974389] c2 [] (__release_extent_node+0xc8/0x168) >>>>>>> [H 103098.974425] c2 [] >>>>>>> (f2fs_update_extent_tree_range+0x4a0/0x724) >>>>>>> [H 103098.974459] c2 [] (f2fs_update_extent_cache+0x19c/0x1b0) >>>>>>> [H 103098.974495] c2 [] (f2fs_outplace_write_data+0x74/0xf0) >>>>>>> [H 103098.974525] c2 [] (f2fs_do_write_data_page+0x3e4/0x6c8) >>>>>>> [H 103098.974552] c2 [] >>>>>>> (f2fs_write_single_data_page+0x478/0xab0) >>>>>>> [H 103098.974574] c2 [] (f2fs_write_cache_pages+0x454/0xaac) >>>>>>> [H 103098.974596] c2 [] (__f2fs_write_data_pages+0x40c/0x4f0) >>>>>>> [H 103098.974617] c2 [] (f2fs_write_data_pages+0x30/0x40) >>>>>>> [H 103098.974645] c2 [] (do_writepages+0x18c/0x3e8) >>>>>>> [H 103098.974678] c2 [] (__writeback_single_inode+0x48/0x498) >>>>>>> [H 103098.974720] c2 [] (writeback_sb_inodes+0x454/0x9b0) >>>>>>> [H 103098.974754] c2 [] (__writeback_inodes_wb+0x198/0x224) >>>>>>> [H 103098.974788] c2 [] (wb_writeback+0x1c0/0x698) >>>>>>> [H 103098.974819] c2 [] (wb_do_writeback+0x420/0x54c) >>>>>>> [H 103098.974853] c2 [] (wb_workfn+0xe4/0x388) >>>>>> >>>> >>