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=-18.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,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 4A671C432BE for ; Wed, 1 Sep 2021 06:58:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2B67E61059 for ; Wed, 1 Sep 2021 06:58:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242444AbhIAG7N (ORCPT ); Wed, 1 Sep 2021 02:59:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:50360 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242438AbhIAG7G (ORCPT ); Wed, 1 Sep 2021 02:59:06 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2C57E61059; Wed, 1 Sep 2021 06:58:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1630479489; bh=UDf23VkSQBll3+1obTTg9ARewCWWGy1famjA2V95Yc4=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=U7pZV2/d9xkrVU3nQ0HTtyGfpFerF4/yzkGczHKSm2VhHtsLWQpHMfINQGnBWqhtZ 8HqwdoSetWqzVClCHN8Ue7l5JaDg6j26GVzggGsIqhP8TfBhKdazF7c11WOslklhKX x/h8zOY7pEriAy9wkT4SLXJsLHZBTLsmBrjJ1x/kLxdeIOCEH9N3ZLlRL/rZtVLKqx juAkWFn7OPx7vBO2iL8CAxJuXSm8s83trr0dMnWr58nqc3G16KVEye5DfV00U6DEYZ DGKPIrdMCkrgSN2sz/e/q8Oj6iV0IMqmgOAnC19CpzxV8gPOYh5Myq4VkGaAIE36fi 3aPYbBD34ldNQ== Subject: Re: [f2fs-dev] [PATCH v3] f2fs: introduce fragment allocation mode mount option To: Daeho Jeong , linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, kernel-team@android.com Cc: Daeho Jeong References: <20210831051037.3108944-1-daeho43@gmail.com> From: Chao Yu Message-ID: <33e7e327-5318-e30f-4419-42497fe90b31@kernel.org> Date: Wed, 1 Sep 2021 14:58:06 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: <20210831051037.3108944-1-daeho43@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/8/31 13:10, Daeho Jeong wrote: > From: Daeho Jeong > > Added three options into "mode=" mount option to make it possible for > developers to make the filesystem fragmented or simulate filesystem > fragmentation/after-GC situation itself. The developers use these modes > to understand filesystem fragmentation/after-GC condition well, > and eventually get some insights to handle them better. > > "fragment:segment": f2fs allocates a new segment in ramdom position. > With this, we can simulate the after-GC condition. > "fragment:fixed_block" : We can scatter block allocation with > "fragment_chunk_size" and "fragment_hole_size" sysfs > nodes. f2fs will allocate blocks > in a chunk and make a hole in the length of > by turns in a newly allocated free > segment. > "fragment:rand_block" : Working like "fragment:fixed_block" mode, but > added some randomness to both chunk and hole size. So, > f2fs will allocate 1.. blocks in a > chunk and make a hole in the nodes. f2fs will allocate > 1.. blocks in a chunk and make a > hole in the length of 1.. by turns > in a newly allocated free segment. > > Signed-off-by: Daeho Jeong > --- > v3: divided "fragment:block" mode and fixed a race condition related to > making chunks. > v2: changed mode name and added sysfs nodes to control the fragmentation > pattern. > --- > Documentation/ABI/testing/sysfs-fs-f2fs | 24 ++++++++++++++++++++ > Documentation/filesystems/f2fs.rst | 20 +++++++++++++++++ > fs/f2fs/f2fs.h | 21 ++++++++++++++++-- > fs/f2fs/gc.c | 5 ++++- > fs/f2fs/segment.c | 29 +++++++++++++++++++++++-- > fs/f2fs/segment.h | 1 + > fs/f2fs/super.c | 14 ++++++++++++ > fs/f2fs/sysfs.c | 20 +++++++++++++++++ > 8 files changed, 129 insertions(+), 5 deletions(-) > > diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs > index f627e705e663..d56ecfd16abf 100644 > --- a/Documentation/ABI/testing/sysfs-fs-f2fs > +++ b/Documentation/ABI/testing/sysfs-fs-f2fs > @@ -512,3 +512,27 @@ Date: July 2021 > Contact: "Daeho Jeong" > Description: You can control the multiplier value of bdi device readahead window size > between 2 (default) and 256 for POSIX_FADV_SEQUENTIAL advise option. > + > +What: /sys/fs/f2fs//fragment_chunk_size > +Date: August 2021 > +Contact: "Daeho Jeong" > +Description: With "mode=fragment:fixed_block" and "mode=fragment:rand_block" mount options, > + we can scatter block allocation. Using this node, in "fragment:fixed_block" > + mode, f2fs will allocate blocks in a chunk and make > + a hole in the length of by turns in a newly allocated > + free segment. Plus, in "fragment:rand_block" mode, f2fs will allocate > + 1.. blocks in a chunk and make a hole in the length of > + 1.. by turns. This value can be set between 1..512 and > + the default value is 4. > + > +What: /sys/fs/f2fs//fragment_hole_size > +Date: August 2021 > +Contact: "Daeho Jeong" > +Description: With "mode=fragment:fixed_block" and "mode=fragment:rand_block" mount options, > + we can scatter block allocation. Using this node, in "fragment:fixed_block" > + mode, f2fs will allocate blocks in a chunk and make > + a hole in the length of by turns in a newly allocated > + free segment. Plus, in "fragment:rand_block" mode, f2fs will allocate > + 1.. blocks in a chunk and make a hole in the length of > + 1.. by turns. This value can be set between 1..512 and > + the default value is 4. > diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst > index 09de6ebbbdfa..c58d300d2f41 100644 > --- a/Documentation/filesystems/f2fs.rst > +++ b/Documentation/filesystems/f2fs.rst > @@ -201,6 +201,26 @@ fault_type=%d Support configuring fault injection type, should be > mode=%s Control block allocation mode which supports "adaptive" > and "lfs". In "lfs" mode, there should be no random > writes towards main area. > + "fragment:segment", "fragment:fixed_block" and "fragment:rand_block" > + are newly added here. These are developer options for experiments > + to make the filesystem fragmented or simulate filesystem > + fragmentation/after-GC situation itself. The developers use these > + modes to understand filesystem fragmentation/after-GC condition well, > + and eventually get some insights to handle them better. > + In "fragment:segment", f2fs allocates a new segment in ramdom > + position. With this, we can simulate the after-GC condition. > + In "fragment:fixed_block" and "fragment:rand_block", we can scatter > + block allocation with "fragment_chunk_size" and "fragment_hole_size" > + sysfs nodes. In "fragment:fixed_block" mode, f2fs will allocate > + blocks in a chunk and make a hole in the length > + of by turns in a newly allocated free segment. > + But, in "fragment:rand_block" mode, f2fs adds some randomness to > + both chunk and hole size. So, f2fs will allocate > + 1.. blocks in a chunk and make a hole in the > + length of 1.. by turns. With these, the newly > + allocated blocks will be scattered throughout the whole partition. > + Please, use these options for your experiments and we strongly > + recommend to re-format the filesystem after using these options. > io_bits=%u Set the bit size of write IO requests. It should be set > with "mode=lfs". > usrquota Enable plain user disk quota accounting. > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > index c24f03e054cb..9f9368405ab1 100644 > --- a/fs/f2fs/f2fs.h > +++ b/fs/f2fs/f2fs.h > @@ -1285,8 +1285,11 @@ enum { > }; > > enum { > - FS_MODE_ADAPTIVE, /* use both lfs/ssr allocation */ > - FS_MODE_LFS, /* use lfs allocation only */ > + FS_MODE_ADAPTIVE, /* use both lfs/ssr allocation */ > + FS_MODE_LFS, /* use lfs allocation only */ > + FS_MODE_FRAGMENT_SEG, /* segment fragmentation mode */ > + FS_MODE_FRAGMENT_FIXED_BLK, /* fixed block fragmentation mode */ > + FS_MODE_FRAGMENT_RAND_BLK, /* randomized block fragmentation mode */ > }; > > enum { > @@ -1757,6 +1760,9 @@ struct f2fs_sb_info { > > unsigned long seq_file_ra_mul; /* multiplier for ra_pages of seq. files in fadvise */ > > + int fragment_chunk_size; /* the chunk size for block fragmentation mode */ > + int fragment_hole_size; /* the hole size for block fragmentation mode */ > + > #ifdef CONFIG_F2FS_FS_COMPRESSION > struct kmem_cache *page_array_slab; /* page array entry */ > unsigned int page_array_slab_size; /* default page array slab size */ > @@ -3517,6 +3523,17 @@ unsigned int f2fs_usable_segs_in_sec(struct f2fs_sb_info *sbi, > unsigned int f2fs_usable_blks_in_seg(struct f2fs_sb_info *sbi, > unsigned int segno); > > +#define DEF_FRAGMENT_SIZE 4 > +#define MIN_FRAGMENT_SIZE 1 > +#define MAX_FRAGMENT_SIZE 512 > + > +static inline bool f2fs_fragment_mode(struct f2fs_sb_info *sbi) > +{ > + return F2FS_OPTION(sbi).fs_mode == FS_MODE_FRAGMENT_SEG || > + F2FS_OPTION(sbi).fs_mode == FS_MODE_FRAGMENT_FIXED_BLK || > + F2FS_OPTION(sbi).fs_mode == FS_MODE_FRAGMENT_RAND_BLK; > +} > + > /* > * checkpoint.c > */ > diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c > index 2c18443972b6..14046fb19a20 100644 > --- a/fs/f2fs/gc.c > +++ b/fs/f2fs/gc.c > @@ -14,6 +14,7 @@ > #include > #include > #include > +#include > > #include "f2fs.h" > #include "node.h" > @@ -257,7 +258,9 @@ static void select_policy(struct f2fs_sb_info *sbi, int gc_type, > p->max_search = sbi->max_victim_search; > > /* let's select beginning hot/small space first in no_heap mode*/ > - if (test_opt(sbi, NOHEAP) && > + if (f2fs_fragment_mode(sbi)) if (F2FS_OPTION(sbi).fs_mode == FS_MODE_FRAGMENT_SEG)? It needs to randomize position of next segment only in fragment_seg mode? IIRC. > + p->offset = prandom_u32() % (MAIN_SECS(sbi) * sbi->segs_per_sec); > + else if (test_opt(sbi, NOHEAP) && > (type == CURSEG_HOT_DATA || IS_NODESEG(type))) > p->offset = 0; > else > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > index a135d2247415..f064e439f2e0 100644 > --- a/fs/f2fs/segment.c > +++ b/fs/f2fs/segment.c > @@ -15,6 +15,7 @@ > #include > #include > #include > +#include > > #include "f2fs.h" > #include "segment.h" > @@ -2630,6 +2631,8 @@ static unsigned int __get_next_segno(struct f2fs_sb_info *sbi, int type) > unsigned short seg_type = curseg->seg_type; > > sanity_check_seg_type(sbi, seg_type); > + if (f2fs_fragment_mode(sbi)) Ditto, Thanks, > + return prandom_u32() % (MAIN_SECS(sbi) * sbi->segs_per_sec); > > /* if segs_per_sec is large than 1, we need to keep original policy. */ > if (__is_large_section(sbi)) > @@ -2681,6 +2684,11 @@ static void new_curseg(struct f2fs_sb_info *sbi, int type, bool new_sec) > curseg->next_segno = segno; > reset_curseg(sbi, type, 1); > curseg->alloc_type = LFS; > + if (F2FS_OPTION(sbi).fs_mode == FS_MODE_FRAGMENT_FIXED_BLK) > + curseg->fragment_remained_chunk = sbi->fragment_chunk_size; > + else if (F2FS_OPTION(sbi).fs_mode == FS_MODE_FRAGMENT_RAND_BLK) > + curseg->fragment_remained_chunk = > + prandom_u32() % sbi->fragment_chunk_size + 1; > } > > static int __next_free_blkoff(struct f2fs_sb_info *sbi, > @@ -2707,12 +2715,29 @@ static int __next_free_blkoff(struct f2fs_sb_info *sbi, > static void __refresh_next_blkoff(struct f2fs_sb_info *sbi, > struct curseg_info *seg) > { > - if (seg->alloc_type == SSR) > + if (seg->alloc_type == SSR) { > seg->next_blkoff = > __next_free_blkoff(sbi, seg->segno, > seg->next_blkoff + 1); > - else > + } else { > seg->next_blkoff++; > + if (F2FS_OPTION(sbi).fs_mode == FS_MODE_FRAGMENT_FIXED_BLK) { > + if (--seg->fragment_remained_chunk <= 0) { > + seg->fragment_remained_chunk = > + sbi->fragment_chunk_size; > + seg->next_blkoff += > + sbi->fragment_hole_size; > + } > + } else if (F2FS_OPTION(sbi).fs_mode == FS_MODE_FRAGMENT_RAND_BLK) { > + /* To allocate block chunks in different sizes, use random number */ > + if (--seg->fragment_remained_chunk <= 0) { > + seg->fragment_remained_chunk = > + prandom_u32() % sbi->fragment_chunk_size + 1; > + seg->next_blkoff += > + prandom_u32() % sbi->fragment_hole_size + 1; > + } > + } > + } > } > > bool f2fs_segment_has_free_slot(struct f2fs_sb_info *sbi, int segno) > diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h > index 89fff258727d..46fde9f3f28e 100644 > --- a/fs/f2fs/segment.h > +++ b/fs/f2fs/segment.h > @@ -314,6 +314,7 @@ struct curseg_info { > unsigned short next_blkoff; /* next block offset to write */ > unsigned int zone; /* current zone number */ > unsigned int next_segno; /* preallocated segment */ > + int fragment_remained_chunk; /* remained block size in a chunk for block fragmentation mode */ > bool inited; /* indicate inmem log is inited */ > }; > > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c > index 49e153fd8183..60067b6d9fea 100644 > --- a/fs/f2fs/super.c > +++ b/fs/f2fs/super.c > @@ -817,6 +817,12 @@ static int parse_options(struct super_block *sb, char *options, bool is_remount) > F2FS_OPTION(sbi).fs_mode = FS_MODE_ADAPTIVE; > } else if (!strcmp(name, "lfs")) { > F2FS_OPTION(sbi).fs_mode = FS_MODE_LFS; > + } else if (!strcmp(name, "fragment:segment")) { > + F2FS_OPTION(sbi).fs_mode = FS_MODE_FRAGMENT_SEG; > + } else if (!strcmp(name, "fragment:fixed_block")) { > + F2FS_OPTION(sbi).fs_mode = FS_MODE_FRAGMENT_FIXED_BLK; > + } else if (!strcmp(name, "fragment:rand_block")) { > + F2FS_OPTION(sbi).fs_mode = FS_MODE_FRAGMENT_RAND_BLK; > } else { > kfree(name); > return -EINVAL; > @@ -1897,6 +1903,12 @@ static int f2fs_show_options(struct seq_file *seq, struct dentry *root) > seq_puts(seq, "adaptive"); > else if (F2FS_OPTION(sbi).fs_mode == FS_MODE_LFS) > seq_puts(seq, "lfs"); > + else if (F2FS_OPTION(sbi).fs_mode == FS_MODE_FRAGMENT_SEG) > + seq_puts(seq, "fragment:segment"); > + else if (F2FS_OPTION(sbi).fs_mode == FS_MODE_FRAGMENT_FIXED_BLK) > + seq_puts(seq, "fragment:fixed_block"); > + else if (F2FS_OPTION(sbi).fs_mode == FS_MODE_FRAGMENT_RAND_BLK) > + seq_puts(seq, "fragment:rand_block"); > seq_printf(seq, ",active_logs=%u", F2FS_OPTION(sbi).active_logs); > if (test_opt(sbi, RESERVE_ROOT)) > seq_printf(seq, ",reserve_root=%u,resuid=%u,resgid=%u", > @@ -3515,6 +3527,8 @@ static void init_sb_info(struct f2fs_sb_info *sbi) > sbi->max_victim_search = DEF_MAX_VICTIM_SEARCH; > sbi->migration_granularity = sbi->segs_per_sec; > sbi->seq_file_ra_mul = MIN_RA_MUL; > + sbi->fragment_chunk_size = DEF_FRAGMENT_SIZE; > + sbi->fragment_hole_size = DEF_FRAGMENT_SIZE; > > sbi->dir_level = DEF_DIR_LEVEL; > sbi->interval_time[CP_TIME] = DEF_CP_INTERVAL; > diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c > index a1a3e0f6d658..ab34b3c2e09d 100644 > --- a/fs/f2fs/sysfs.c > +++ b/fs/f2fs/sysfs.c > @@ -551,6 +551,22 @@ static ssize_t __sbi_store(struct f2fs_attr *a, > return count; > } > > + if (!strcmp(a->attr.name, "fragment_chunk_size")) { > + if (t >= MIN_FRAGMENT_SIZE && t <= MAX_FRAGMENT_SIZE) > + sbi->fragment_chunk_size = t; > + else > + return -EINVAL; > + return count; > + } > + > + if (!strcmp(a->attr.name, "fragment_hole_size")) { > + if (t >= MIN_FRAGMENT_SIZE && t <= MAX_FRAGMENT_SIZE) > + sbi->fragment_hole_size = t; > + else > + return -EINVAL; > + return count; > + } > + > *ui = (unsigned int)t; > > return count; > @@ -781,6 +797,8 @@ F2FS_RW_ATTR(ATGC_INFO, atgc_management, atgc_age_threshold, age_threshold); > F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, seq_file_ra_mul, seq_file_ra_mul); > F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, gc_segment_mode, gc_segment_mode); > F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, gc_reclaimed_segments, gc_reclaimed_segs); > +F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, fragment_chunk_size, fragment_chunk_size); > +F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, fragment_hole_size, fragment_hole_size); > > #define ATTR_LIST(name) (&f2fs_attr_##name.attr) > static struct attribute *f2fs_attrs[] = { > @@ -859,6 +877,8 @@ static struct attribute *f2fs_attrs[] = { > ATTR_LIST(seq_file_ra_mul), > ATTR_LIST(gc_segment_mode), > ATTR_LIST(gc_reclaimed_segments), > + ATTR_LIST(fragment_chunk_size), > + ATTR_LIST(fragment_hole_size), > NULL, > }; > ATTRIBUTE_GROUPS(f2fs); > 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=-16.3 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 CE0CFC4320A for ; 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bh=Wzi6BM088/giacgK0bd5g8Iy5/Iq18TjkXG0wUtvw5w=; b=cuydC/BC/2VGAt8UrhzqzsOFOi MTHGsGtDDU5lL6mRn0HWulszLZcgXue7mBXZsPbfVM/RX+S+pAGYhKjVd9xVt/8LnNvuKDVlsfAy3 zDURx1JdBWE5f1n1XFNK9RNF6vtxuyqiwGPaO2xmhLtNUu9eojc16LsWzXVPFZ8uZf9g=; Received: from mail.kernel.org ([198.145.29.99]) by sfi-mx-2.v28.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.92.3) id 1mLKCM-0000RC-OY for linux-f2fs-devel@lists.sourceforge.net; Wed, 01 Sep 2021 06:58:16 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2C57E61059; Wed, 1 Sep 2021 06:58:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1630479489; bh=UDf23VkSQBll3+1obTTg9ARewCWWGy1famjA2V95Yc4=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=U7pZV2/d9xkrVU3nQ0HTtyGfpFerF4/yzkGczHKSm2VhHtsLWQpHMfINQGnBWqhtZ 8HqwdoSetWqzVClCHN8Ue7l5JaDg6j26GVzggGsIqhP8TfBhKdazF7c11WOslklhKX x/h8zOY7pEriAy9wkT4SLXJsLHZBTLsmBrjJ1x/kLxdeIOCEH9N3ZLlRL/rZtVLKqx juAkWFn7OPx7vBO2iL8CAxJuXSm8s83trr0dMnWr58nqc3G16KVEye5DfV00U6DEYZ DGKPIrdMCkrgSN2sz/e/q8Oj6iV0IMqmgOAnC19CpzxV8gPOYh5Myq4VkGaAIE36fi 3aPYbBD34ldNQ== To: Daeho Jeong , linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, kernel-team@android.com References: <20210831051037.3108944-1-daeho43@gmail.com> From: Chao Yu Message-ID: <33e7e327-5318-e30f-4419-42497fe90b31@kernel.org> Date: Wed, 1 Sep 2021 14:58:06 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: <20210831051037.3108944-1-daeho43@gmail.com> Content-Language: en-US X-Headers-End: 1mLKCM-0000RC-OY Subject: Re: [f2fs-dev] [PATCH v3] f2fs: introduce fragment allocation mode mount option X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Daeho Jeong Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net On 2021/8/31 13:10, Daeho Jeong wrote: > From: Daeho Jeong > > Added three options into "mode=" mount option to make it possible for > developers to make the filesystem fragmented or simulate filesystem > fragmentation/after-GC situation itself. The developers use these modes > to understand filesystem fragmentation/after-GC condition well, > and eventually get some insights to handle them better. > > "fragment:segment": f2fs allocates a new segment in ramdom position. > With this, we can simulate the after-GC condition. > "fragment:fixed_block" : We can scatter block allocation with > "fragment_chunk_size" and "fragment_hole_size" sysfs > nodes. f2fs will allocate blocks > in a chunk and make a hole in the length of > by turns in a newly allocated free > segment. > "fragment:rand_block" : Working like "fragment:fixed_block" mode, but > added some randomness to both chunk and hole size. So, > f2fs will allocate 1.. blocks in a > chunk and make a hole in the nodes. f2fs will allocate > 1.. blocks in a chunk and make a > hole in the length of 1.. by turns > in a newly allocated free segment. > > Signed-off-by: Daeho Jeong > --- > v3: divided "fragment:block" mode and fixed a race condition related to > making chunks. > v2: changed mode name and added sysfs nodes to control the fragmentation > pattern. > --- > Documentation/ABI/testing/sysfs-fs-f2fs | 24 ++++++++++++++++++++ > Documentation/filesystems/f2fs.rst | 20 +++++++++++++++++ > fs/f2fs/f2fs.h | 21 ++++++++++++++++-- > fs/f2fs/gc.c | 5 ++++- > fs/f2fs/segment.c | 29 +++++++++++++++++++++++-- > fs/f2fs/segment.h | 1 + > fs/f2fs/super.c | 14 ++++++++++++ > fs/f2fs/sysfs.c | 20 +++++++++++++++++ > 8 files changed, 129 insertions(+), 5 deletions(-) > > diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs > index f627e705e663..d56ecfd16abf 100644 > --- a/Documentation/ABI/testing/sysfs-fs-f2fs > +++ b/Documentation/ABI/testing/sysfs-fs-f2fs > @@ -512,3 +512,27 @@ Date: July 2021 > Contact: "Daeho Jeong" > Description: You can control the multiplier value of bdi device readahead window size > between 2 (default) and 256 for POSIX_FADV_SEQUENTIAL advise option. > + > +What: /sys/fs/f2fs//fragment_chunk_size > +Date: August 2021 > +Contact: "Daeho Jeong" > +Description: With "mode=fragment:fixed_block" and "mode=fragment:rand_block" mount options, > + we can scatter block allocation. Using this node, in "fragment:fixed_block" > + mode, f2fs will allocate blocks in a chunk and make > + a hole in the length of by turns in a newly allocated > + free segment. Plus, in "fragment:rand_block" mode, f2fs will allocate > + 1.. blocks in a chunk and make a hole in the length of > + 1.. by turns. This value can be set between 1..512 and > + the default value is 4. > + > +What: /sys/fs/f2fs//fragment_hole_size > +Date: August 2021 > +Contact: "Daeho Jeong" > +Description: With "mode=fragment:fixed_block" and "mode=fragment:rand_block" mount options, > + we can scatter block allocation. Using this node, in "fragment:fixed_block" > + mode, f2fs will allocate blocks in a chunk and make > + a hole in the length of by turns in a newly allocated > + free segment. Plus, in "fragment:rand_block" mode, f2fs will allocate > + 1.. blocks in a chunk and make a hole in the length of > + 1.. by turns. This value can be set between 1..512 and > + the default value is 4. > diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst > index 09de6ebbbdfa..c58d300d2f41 100644 > --- a/Documentation/filesystems/f2fs.rst > +++ b/Documentation/filesystems/f2fs.rst > @@ -201,6 +201,26 @@ fault_type=%d Support configuring fault injection type, should be > mode=%s Control block allocation mode which supports "adaptive" > and "lfs". In "lfs" mode, there should be no random > writes towards main area. > + "fragment:segment", "fragment:fixed_block" and "fragment:rand_block" > + are newly added here. These are developer options for experiments > + to make the filesystem fragmented or simulate filesystem > + fragmentation/after-GC situation itself. The developers use these > + modes to understand filesystem fragmentation/after-GC condition well, > + and eventually get some insights to handle them better. > + In "fragment:segment", f2fs allocates a new segment in ramdom > + position. With this, we can simulate the after-GC condition. > + In "fragment:fixed_block" and "fragment:rand_block", we can scatter > + block allocation with "fragment_chunk_size" and "fragment_hole_size" > + sysfs nodes. In "fragment:fixed_block" mode, f2fs will allocate > + blocks in a chunk and make a hole in the length > + of by turns in a newly allocated free segment. > + But, in "fragment:rand_block" mode, f2fs adds some randomness to > + both chunk and hole size. So, f2fs will allocate > + 1.. blocks in a chunk and make a hole in the > + length of 1.. by turns. With these, the newly > + allocated blocks will be scattered throughout the whole partition. > + Please, use these options for your experiments and we strongly > + recommend to re-format the filesystem after using these options. > io_bits=%u Set the bit size of write IO requests. It should be set > with "mode=lfs". > usrquota Enable plain user disk quota accounting. > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > index c24f03e054cb..9f9368405ab1 100644 > --- a/fs/f2fs/f2fs.h > +++ b/fs/f2fs/f2fs.h > @@ -1285,8 +1285,11 @@ enum { > }; > > enum { > - FS_MODE_ADAPTIVE, /* use both lfs/ssr allocation */ > - FS_MODE_LFS, /* use lfs allocation only */ > + FS_MODE_ADAPTIVE, /* use both lfs/ssr allocation */ > + FS_MODE_LFS, /* use lfs allocation only */ > + FS_MODE_FRAGMENT_SEG, /* segment fragmentation mode */ > + FS_MODE_FRAGMENT_FIXED_BLK, /* fixed block fragmentation mode */ > + FS_MODE_FRAGMENT_RAND_BLK, /* randomized block fragmentation mode */ > }; > > enum { > @@ -1757,6 +1760,9 @@ struct f2fs_sb_info { > > unsigned long seq_file_ra_mul; /* multiplier for ra_pages of seq. files in fadvise */ > > + int fragment_chunk_size; /* the chunk size for block fragmentation mode */ > + int fragment_hole_size; /* the hole size for block fragmentation mode */ > + > #ifdef CONFIG_F2FS_FS_COMPRESSION > struct kmem_cache *page_array_slab; /* page array entry */ > unsigned int page_array_slab_size; /* default page array slab size */ > @@ -3517,6 +3523,17 @@ unsigned int f2fs_usable_segs_in_sec(struct f2fs_sb_info *sbi, > unsigned int f2fs_usable_blks_in_seg(struct f2fs_sb_info *sbi, > unsigned int segno); > > +#define DEF_FRAGMENT_SIZE 4 > +#define MIN_FRAGMENT_SIZE 1 > +#define MAX_FRAGMENT_SIZE 512 > + > +static inline bool f2fs_fragment_mode(struct f2fs_sb_info *sbi) > +{ > + return F2FS_OPTION(sbi).fs_mode == FS_MODE_FRAGMENT_SEG || > + F2FS_OPTION(sbi).fs_mode == FS_MODE_FRAGMENT_FIXED_BLK || > + F2FS_OPTION(sbi).fs_mode == FS_MODE_FRAGMENT_RAND_BLK; > +} > + > /* > * checkpoint.c > */ > diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c > index 2c18443972b6..14046fb19a20 100644 > --- a/fs/f2fs/gc.c > +++ b/fs/f2fs/gc.c > @@ -14,6 +14,7 @@ > #include > #include > #include > +#include > > #include "f2fs.h" > #include "node.h" > @@ -257,7 +258,9 @@ static void select_policy(struct f2fs_sb_info *sbi, int gc_type, > p->max_search = sbi->max_victim_search; > > /* let's select beginning hot/small space first in no_heap mode*/ > - if (test_opt(sbi, NOHEAP) && > + if (f2fs_fragment_mode(sbi)) if (F2FS_OPTION(sbi).fs_mode == FS_MODE_FRAGMENT_SEG)? It needs to randomize position of next segment only in fragment_seg mode? IIRC. > + p->offset = prandom_u32() % (MAIN_SECS(sbi) * sbi->segs_per_sec); > + else if (test_opt(sbi, NOHEAP) && > (type == CURSEG_HOT_DATA || IS_NODESEG(type))) > p->offset = 0; > else > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > index a135d2247415..f064e439f2e0 100644 > --- a/fs/f2fs/segment.c > +++ b/fs/f2fs/segment.c > @@ -15,6 +15,7 @@ > #include > #include > #include > +#include > > #include "f2fs.h" > #include "segment.h" > @@ -2630,6 +2631,8 @@ static unsigned int __get_next_segno(struct f2fs_sb_info *sbi, int type) > unsigned short seg_type = curseg->seg_type; > > sanity_check_seg_type(sbi, seg_type); > + if (f2fs_fragment_mode(sbi)) Ditto, Thanks, > + return prandom_u32() % (MAIN_SECS(sbi) * sbi->segs_per_sec); > > /* if segs_per_sec is large than 1, we need to keep original policy. */ > if (__is_large_section(sbi)) > @@ -2681,6 +2684,11 @@ static void new_curseg(struct f2fs_sb_info *sbi, int type, bool new_sec) > curseg->next_segno = segno; > reset_curseg(sbi, type, 1); > curseg->alloc_type = LFS; > + if (F2FS_OPTION(sbi).fs_mode == FS_MODE_FRAGMENT_FIXED_BLK) > + curseg->fragment_remained_chunk = sbi->fragment_chunk_size; > + else if (F2FS_OPTION(sbi).fs_mode == FS_MODE_FRAGMENT_RAND_BLK) > + curseg->fragment_remained_chunk = > + prandom_u32() % sbi->fragment_chunk_size + 1; > } > > static int __next_free_blkoff(struct f2fs_sb_info *sbi, > @@ -2707,12 +2715,29 @@ static int __next_free_blkoff(struct f2fs_sb_info *sbi, > static void __refresh_next_blkoff(struct f2fs_sb_info *sbi, > struct curseg_info *seg) > { > - if (seg->alloc_type == SSR) > + if (seg->alloc_type == SSR) { > seg->next_blkoff = > __next_free_blkoff(sbi, seg->segno, > seg->next_blkoff + 1); > - else > + } else { > seg->next_blkoff++; > + if (F2FS_OPTION(sbi).fs_mode == FS_MODE_FRAGMENT_FIXED_BLK) { > + if (--seg->fragment_remained_chunk <= 0) { > + seg->fragment_remained_chunk = > + sbi->fragment_chunk_size; > + seg->next_blkoff += > + sbi->fragment_hole_size; > + } > + } else if (F2FS_OPTION(sbi).fs_mode == FS_MODE_FRAGMENT_RAND_BLK) { > + /* To allocate block chunks in different sizes, use random number */ > + if (--seg->fragment_remained_chunk <= 0) { > + seg->fragment_remained_chunk = > + prandom_u32() % sbi->fragment_chunk_size + 1; > + seg->next_blkoff += > + prandom_u32() % sbi->fragment_hole_size + 1; > + } > + } > + } > } > > bool f2fs_segment_has_free_slot(struct f2fs_sb_info *sbi, int segno) > diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h > index 89fff258727d..46fde9f3f28e 100644 > --- a/fs/f2fs/segment.h > +++ b/fs/f2fs/segment.h > @@ -314,6 +314,7 @@ struct curseg_info { > unsigned short next_blkoff; /* next block offset to write */ > unsigned int zone; /* current zone number */ > unsigned int next_segno; /* preallocated segment */ > + int fragment_remained_chunk; /* remained block size in a chunk for block fragmentation mode */ > bool inited; /* indicate inmem log is inited */ > }; > > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c > index 49e153fd8183..60067b6d9fea 100644 > --- a/fs/f2fs/super.c > +++ b/fs/f2fs/super.c > @@ -817,6 +817,12 @@ static int parse_options(struct super_block *sb, char *options, bool is_remount) > F2FS_OPTION(sbi).fs_mode = FS_MODE_ADAPTIVE; > } else if (!strcmp(name, "lfs")) { > F2FS_OPTION(sbi).fs_mode = FS_MODE_LFS; > + } else if (!strcmp(name, "fragment:segment")) { > + F2FS_OPTION(sbi).fs_mode = FS_MODE_FRAGMENT_SEG; > + } else if (!strcmp(name, "fragment:fixed_block")) { > + F2FS_OPTION(sbi).fs_mode = FS_MODE_FRAGMENT_FIXED_BLK; > + } else if (!strcmp(name, "fragment:rand_block")) { > + F2FS_OPTION(sbi).fs_mode = FS_MODE_FRAGMENT_RAND_BLK; > } else { > kfree(name); > return -EINVAL; > @@ -1897,6 +1903,12 @@ static int f2fs_show_options(struct seq_file *seq, struct dentry *root) > seq_puts(seq, "adaptive"); > else if (F2FS_OPTION(sbi).fs_mode == FS_MODE_LFS) > seq_puts(seq, "lfs"); > + else if (F2FS_OPTION(sbi).fs_mode == FS_MODE_FRAGMENT_SEG) > + seq_puts(seq, "fragment:segment"); > + else if (F2FS_OPTION(sbi).fs_mode == FS_MODE_FRAGMENT_FIXED_BLK) > + seq_puts(seq, "fragment:fixed_block"); > + else if (F2FS_OPTION(sbi).fs_mode == FS_MODE_FRAGMENT_RAND_BLK) > + seq_puts(seq, "fragment:rand_block"); > seq_printf(seq, ",active_logs=%u", F2FS_OPTION(sbi).active_logs); > if (test_opt(sbi, RESERVE_ROOT)) > seq_printf(seq, ",reserve_root=%u,resuid=%u,resgid=%u", > @@ -3515,6 +3527,8 @@ static void init_sb_info(struct f2fs_sb_info *sbi) > sbi->max_victim_search = DEF_MAX_VICTIM_SEARCH; > sbi->migration_granularity = sbi->segs_per_sec; > sbi->seq_file_ra_mul = MIN_RA_MUL; > + sbi->fragment_chunk_size = DEF_FRAGMENT_SIZE; > + sbi->fragment_hole_size = DEF_FRAGMENT_SIZE; > > sbi->dir_level = DEF_DIR_LEVEL; > sbi->interval_time[CP_TIME] = DEF_CP_INTERVAL; > diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c > index a1a3e0f6d658..ab34b3c2e09d 100644 > --- a/fs/f2fs/sysfs.c > +++ b/fs/f2fs/sysfs.c > @@ -551,6 +551,22 @@ static ssize_t __sbi_store(struct f2fs_attr *a, > return count; > } > > + if (!strcmp(a->attr.name, "fragment_chunk_size")) { > + if (t >= MIN_FRAGMENT_SIZE && t <= MAX_FRAGMENT_SIZE) > + sbi->fragment_chunk_size = t; > + else > + return -EINVAL; > + return count; > + } > + > + if (!strcmp(a->attr.name, "fragment_hole_size")) { > + if (t >= MIN_FRAGMENT_SIZE && t <= MAX_FRAGMENT_SIZE) > + sbi->fragment_hole_size = t; > + else > + return -EINVAL; > + return count; > + } > + > *ui = (unsigned int)t; > > return count; > @@ -781,6 +797,8 @@ F2FS_RW_ATTR(ATGC_INFO, atgc_management, atgc_age_threshold, age_threshold); > F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, seq_file_ra_mul, seq_file_ra_mul); > F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, gc_segment_mode, gc_segment_mode); > F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, gc_reclaimed_segments, gc_reclaimed_segs); > +F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, fragment_chunk_size, fragment_chunk_size); > +F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, fragment_hole_size, fragment_hole_size); > > #define ATTR_LIST(name) (&f2fs_attr_##name.attr) > static struct attribute *f2fs_attrs[] = { > @@ -859,6 +877,8 @@ static struct attribute *f2fs_attrs[] = { > ATTR_LIST(seq_file_ra_mul), > ATTR_LIST(gc_segment_mode), > ATTR_LIST(gc_reclaimed_segments), > + ATTR_LIST(fragment_chunk_size), > + ATTR_LIST(fragment_hole_size), > NULL, > }; > ATTRIBUTE_GROUPS(f2fs); > _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel