Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756064Ab1CBIZf (ORCPT ); Wed, 2 Mar 2011 03:25:35 -0500 Received: from mail-gw0-f51.google.com ([74.125.83.51]:56482 "EHLO mail-gw0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755793Ab1CBIZc convert rfc822-to-8bit (ORCPT ); Wed, 2 Mar 2011 03:25:32 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=UcYsb2lX78qwp7uds4DfxhSJYcKEUWoY4WZSokLkY91I+D1q1/Gtc3jIXm1jvZ6CRZ EKW9BvI6vMRWnldd26VvsSVCo3aFUtFfZHAVVN9hCEDrHla3nHtAg0U24unREGyNu6la u9cJVcT3LFbtLI6k9KTRflgv8WzPUa7MH5u78= MIME-Version: 1.0 In-Reply-To: References: <20110225010346.GA9019@july> Date: Wed, 2 Mar 2011 17:25:31 +0900 X-Google-Sender-Auth: 2Ks9Fdbl4F20lEi9GacOjXTpJWA Message-ID: Subject: Re: [PATCH v3] fat: Batched discard support for fat From: Kyungmin Park To: Lukas Czerner Cc: OGAWA Hirofumi , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 15765 Lines: 441 On Wed, Mar 2, 2011 at 11:07 AM, Kyungmin Park wrote: > On Mon, Feb 28, 2011 at 9:51 PM, Lukas Czerner wrote: >> On Mon, 28 Feb 2011, Kyungmin Park wrote: >> >>> On Fri, Feb 25, 2011 at 8:17 PM, Lukas Czerner wrote: >>> > On Fri, 25 Feb 2011, Kyungmin Park wrote: >>> > >>> >> From: Kyungmin Park >>> >> >>> >> FAT supports batched discard as ext4. >>> >> >>> >> Cited from Lukas words. >>> >> "The current solution is not ideal because of its bad performance impact. >>> >> So basic idea to improve things is to avoid discarding every time some >>> >> blocks are freed. and instead batching is together into bigger trims, >>> >> which tends to be more effective." >>> >> >>> >> You can find an information in detail at following URLs. >>> >> http://lwn.net/Articles/397538/ >>> >> http://lwn.net/Articles/383933/ >>> >> >>> >> Clearify the meaning of "len" (Cited form Lukas mail) >>> >> >>> >> Let the "O" be free (bytes, blocks, whatever), and "=" be used. >>> >> Now, we have a filesystem like this. >>> >> >>> >> ? OOOO==O===OO===OOOOO==O===O===OOOOOOO=== >>> >> ? ^ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?^ >>> >> ? 0 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?40 >>> >> >>> >> This is how it supposed to wotk if you have called FITIRM with parameters: >>> >> >>> >> start = 0 >>> >> minlen = 2 >>> >> len = 20 >>> >> >>> >> So you will go through (blocks, bytes...) 0 -> 20 >>> >> >>> >> ? OOOO==O===OO===OOOOO==O===O===OOOOOOO=== >>> >> ? ^ ? ? ? ? ? ? ? ? ? ^ >>> >> ? 0 ? ? ? ? ? ? ? ? ? 20 >>> >> >>> >> So, you will call discard on extents: >>> >> >>> >> 0-3 >>> >> You'll skip 6 because is smaller than minlen >>> >> 10-11 >>> >> 15-19 >>> >> >>> >> instead of >>> >> >>> >> 0-3 >>> >> 10-11 >>> >> 15-19 >>> >> 30-36 >>> > >>> > Hi thanks for the next version. And again I have to ask: Did you test it >>> > ? and how ? Did you tried xfstest No. 251 ? Couple of comments bellow. >>> >>> I tested it with your test program. Of course I modified for our >>> environment (eMMC). >> >> Ok, good. >> >>> >>> #include >>> #include >>> #include >>> #include >>> #include >>> >>> struct fstrim_range { >>> ? ? ? ? uint64_t start; >>> ? ? ? ? uint64_t len; >>> ? ? ? ? uint64_t minlen; >>> }; >>> >>> #define FITRIM ? ? ? ? ?_IOWR('X', 121, struct fstrim_range) >>> >>> int main(int argc, char **argv) >>> { >>> ? ? ? ? struct fstrim_range range; >>> ? ? ? ? uint64_t len; >>> ? ? ? ? int fd; >>> >>> ? ? ? ? if (argc < 2) { >>> ? ? ? ? ? ? ? ? fprintf(stderr, "usage: %s mountpoint [size]\n", argv[0]); >>> ? ? ? ? ? ? ? ? return 1; >>> ? ? ? ? } >>> >>> ? ? ? ? if (argc == 3) >>> ? ? ? ? ? ? ? ? len = atoll(argv[1]); >>> ? ? ? ? else >>> ? ? ? ? ? ? ? ? len = ((1UL<<31) - 1); >>> >>> ? ? ? ? range.start = 0; >>> ? ? ? ? range.len = len; >>> ? ? ? ? range.minlen = 256 * 1024; ? ? ?/* Minimum is 256KiB */ >> >> Why exactly you need to set this ? What will happen if the minlen is 0 ? > > It's dependent on eMMC chip. it's for our environment. If it passed > with 0, the code is working but the less than 256KiB trim command is > meaningless. > >> >>> >>> ? ? ? ? fd = open(argv[1], O_RDONLY); >>> ? ? ? ? if (fd < 0) { >>> ? ? ? ? ? ? ? ? perror("open"); >>> ? ? ? ? ? ? ? ? return 1; >>> ? ? ? ? } >>> >>> ? ? ? ? if (ioctl(fd, FITRIM, &range)) { >>> ? ? ? ? ? ? ? ? if (errno == EOPNOTSUPP) >>> ? ? ? ? ? ? ? ? ? ? ? ? fprintf(stderr, "TRIM not supported\n"); >>> ? ? ? ? ? ? ? ? else >>> ? ? ? ? ? ? ? ? ? ? ? ? perror("FITRIM"); >>> ? ? ? ? ? ? ? ? return 1; >>> ? ? ? ? } >>> >>> ? ? ? ? fprintf(stderr, "Trimmed size %llu\n", range.len); >>> >>> ? ? ? ? return 0; >>> } >>> >>> > >>> > Thanks! >>> > -Lukas >>> > >>> >> >>> >> Signed-off-by: Kyungmin Park >>> >> --- >>> >> Changelog v3: >>> >> ? ? ? Adjust the minlen from queue discard_granularity >>> >> ? ? ? Use the corrent len usage >>> >> Changelog v2: >>> >> ? ? ? Use the given start and len as Lukas comments >>> >> ? ? ? Check the queue supports discard feature >>> >> --- >>> >> diff --git a/fs/fat/fat.h b/fs/fat/fat.h >>> >> index f504089..08b53e1 100644 >>> >> --- a/fs/fat/fat.h >>> >> +++ b/fs/fat/fat.h >>> >> @@ -299,6 +299,7 @@ extern int fat_alloc_clusters(struct inode *inode, int *cluster, >>> >> ? ? ? ? ? ? ? ? ? ? ? ? ? ? int nr_cluster); >>> >> ?extern int fat_free_clusters(struct inode *inode, int cluster); >>> >> ?extern int fat_count_free_clusters(struct super_block *sb); >>> >> +extern int fat_trim_fs(struct super_block *sb, struct fstrim_range *range); >>> >> >>> >> ?/* fat/file.c */ >>> >> ?extern long fat_generic_ioctl(struct file *filp, unsigned int cmd, >>> >> diff --git a/fs/fat/fatent.c b/fs/fat/fatent.c >>> >> index b47d2c9..a8e3837 100644 >>> >> --- a/fs/fat/fatent.c >>> >> +++ b/fs/fat/fatent.c >>> >> @@ -1,6 +1,8 @@ >>> >> ?/* >>> >> ? * Copyright (C) 2004, OGAWA Hirofumi >>> >> ? * Released under GPL v2. >>> >> + * >>> >> + * Batched discard support by Kyungmin Park >>> >> ? */ >>> >> >>> >> ?#include >>> >> @@ -541,6 +543,16 @@ out: >>> >> ? ? ? return err; >>> >> ?} >>> >> >>> >> +static int fat_issue_discard(struct super_block *sb, int cluster, int nr_clus) >>> >> +{ >>> >> + ? ? struct msdos_sb_info *sbi = MSDOS_SB(sb); >>> >> + ? ? sector_t block, nr_blocks; >>> >> + >>> >> + ? ? block = fat_clus_to_blknr(sbi, cluster); >>> >> + ? ? nr_blocks = nr_clus * sbi->sec_per_clus; >>> >> + ? ? return sb_issue_discard(sb, block, nr_blocks, GFP_NOFS, 0); >>> >> +} >>> >> + >>> >> ?int fat_free_clusters(struct inode *inode, int cluster) >>> >> ?{ >>> >> ? ? ? struct super_block *sb = inode->i_sb; >>> >> @@ -575,11 +587,7 @@ int fat_free_clusters(struct inode *inode, int cluster) >>> >> ? ? ? ? ? ? ? ? ? ? ? if (cluster != fatent.entry + 1) { >>> >> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? int nr_clus = fatent.entry - first_cl + 1; >>> >> >>> >> - ? ? ? ? ? ? ? ? ? ? ? ? ? ? sb_issue_discard(sb, >>> >> - ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? fat_clus_to_blknr(sbi, first_cl), >>> >> - ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? nr_clus * sbi->sec_per_clus, >>> >> - ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? GFP_NOFS, 0); >>> >> - >>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? fat_issue_discard(sb, first_cl, nr_clus); >>> >> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? first_cl = cluster; >>> >> ? ? ? ? ? ? ? ? ? ? ? } >>> >> ? ? ? ? ? ? ? } >>> >> @@ -683,3 +691,88 @@ out: >>> >> ? ? ? unlock_fat(sbi); >>> >> ? ? ? return err; >>> >> ?} >>> >> + >>> >> +int fat_trim_fs(struct super_block *sb, struct fstrim_range *range) >>> >> +{ >>> >> + ? ? struct msdos_sb_info *sbi = MSDOS_SB(sb); >>> >> + ? ? struct fatent_operations *ops = sbi->fatent_ops; >>> >> + ? ? struct fat_entry fatent; >>> >> + ? ? unsigned long reada_blocks, reada_mask, cur_block; >>> >> + ? ? int err = 0, free, count, entry; >>> >> + ? ? int start, len, minlen, trimmed; >>> >> + >>> >> + ? ? start = range->start >> sb->s_blocksize_bits; >>> >> + ? ? start = start / sbi->sec_per_clus; >>> >> + ? ? len = range->len >> sb->s_blocksize_bits; >>> >> + ? ? len = len / sbi->sec_per_clus; >>> >> + ? ? minlen = range->minlen >> sb->s_blocksize_bits; >>> >> + ? ? minlen = minlen / sbi->sec_per_clus; >>> >> + ? ? trimmed = 0; >>> >> + ? ? count = 0; >>> >> + >>> >> + ? ? lock_fat(sbi); >>> >> + ? ? if (sbi->free_clusters != -1 && sbi->free_clus_valid) >>> >> + ? ? ? ? ? ? goto out; >>> >> + >>> >> + ? ? reada_blocks = FAT_READA_SIZE >> sb->s_blocksize_bits; >>> >> + ? ? reada_mask = reada_blocks - 1; >>> >> + ? ? cur_block = 0; >>> >> + >>> >> + ? ? entry = 0; >>> >> + ? ? free = 0; >>> >> + ? ? fatent_init(&fatent); >>> >> + >>> >> + ? ? if (start < FAT_START_ENT) >>> >> + ? ? ? ? ? ? start = FAT_START_ENT; >>> >> + >>> >> + ? ? fatent_set_entry(&fatent, start); >>> >> + >>> >> + ? ? while (count < sbi->max_cluster) { >>> >> + ? ? ? ? ? ? if (fatent.entry >= sbi->max_cluster) >>> >> + ? ? ? ? ? ? ? ? ? ? fatent.entry = FAT_START_ENT; >>> >> + ? ? ? ? ? ? /* readahead of fat blocks */ >>> >> + ? ? ? ? ? ? if ((cur_block & reada_mask) == 0) { >>> >> + ? ? ? ? ? ? ? ? ? ? unsigned long rest = sbi->fat_length - cur_block; >>> >> + ? ? ? ? ? ? ? ? ? ? fat_ent_reada(sb, &fatent, min(reada_blocks, rest)); >>> > >>> > You really do not need new variable "rest" just for passing it into one >>> > function. Get rid of it. >>> >>> Umm. I don't want to modify it since it's routine is same as >>> free_count codes. I just borrowed it from FAT codes. >>> > >>> >> + ? ? ? ? ? ? } >>> >> + ? ? ? ? ? ? cur_block++; >>> >> + >>> >> + ? ? ? ? ? ? err = fat_ent_read_block(sb, &fatent); >>> >> + ? ? ? ? ? ? if (err) >>> >> + ? ? ? ? ? ? ? ? ? ? goto out; >>> >> + >>> >> + ? ? ? ? ? ? do { >>> >> + ? ? ? ? ? ? ? ? ? ? if (ops->ent_get(&fatent) == FAT_ENT_FREE) { >>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? free++; >>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? if (!entry) >>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? entry = fatent.entry; >>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? if (count >= len && free >= minlen) { >>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? fat_issue_discard(sb, entry, free); >>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? trimmed += free; >> >> I think you can remove this condition completely is you move "done" >> label befor the if (free >= minlen) condition. >> >>> > I really do not understand FAT code very much, but is this right ? >>> > Should not you be setting free = 0 ? >>> Right but count is larger then "len". it will exit at next if (count >>> >= len) goto done statement. >> >> Oh, ok I see. But it proves my point that this code is not very well >> readable. >> >>> >>> > What will happen if you'll end up >>> > in the same branch in next iteration ? -- free will be still set to >>> > previous value+1, bu you'll be discarding next entry. I am sorry but >>> > this whole thing is not very readable. >>> >>> > >>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? } >>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? if (count >= len) >>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? goto done; >> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ^^^^^^^^^^^^^^^^^^ >> this > > Okay I will fix it. >> >>> >> + ? ? ? ? ? ? ? ? ? ? } else if (entry) { >>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? if (free >= minlen) { >>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? fat_issue_discard(sb, entry, free); >>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? trimmed += free; >>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? } >>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? if (count >= len) >>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? goto done; >> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ^^^^^^^^^^^^^^^^^^ >> and this >> >>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? free = 0; >>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? entry = 0; >>> >> + ? ? ? ? ? ? ? ? ? ? } >>> > >>> > I don't not see why you are testing count all the time since it has not been >>> > changed since the "if" condition started. how about doing one test >>> > before the "if" condition ? >>> >>> For looping the whole fat max_cluster size. now start can be any >>> address and if start is a middle point and len is max, then it will >>> search from middle -> end -> start -> middle. The "count" is used for >>> this purpose. >>> >>> Thank you, >>> Kyungmin Park >>> > >> can go here -->> >> ?? ? ? ? ? ? ? ? ? ? ? ? ? if (count >= len) >> ?? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? goto done; >> >>> >> + ? ? ? ? ? ? ? ? ? ? count++; >>> >> + ? ? ? ? ? ? } while (fat_ent_next(sbi, &fatent)); >>> >> + ? ? } How about this code? while (count < sbi->max_cluster) { if (fatent.entry >= sbi->max_cluster) fatent.entry = FAT_START_ENT; /* readahead of fat blocks */ if ((cur_block & reada_mask) == 0) { unsigned long rest = sbi->fat_length - cur_block; fat_ent_reada(sb, &fatent, min(reada_blocks, rest)); } cur_block++; err = fat_ent_read_block(sb, &fatent); if (err) goto out; do { if (ops->ent_get(&fatent) == FAT_ENT_FREE) { free++; if (!entry) entry = fatent.entry; } else if (entry) { /* * Discard if free entry is equal or greater * than minimum length */ if (free >= minlen) { fat_issue_discard(sb, entry, free); trimmed += free; } free = 0; entry = 0; } count++; /* Check the loop count */ if (count >= len) goto done; } while (fat_ent_next(sbi, &fatent)); } done: if (free >= minlen) { fat_issue_discard(sb, entry, free); trimmed += free; } range->len = (trimmed * sbi->sec_per_clus) << sb->s_blocksize_bits; fatent_brelse(&fatent); out: unlock_fat(sbi); return err; >>> >> + ? ? if (free >= minlen) { >>> >> + ? ? ? ? ? ? fat_issue_discard(sb, entry, free); >>> >> + ? ? ? ? ? ? trimmed += free; >>> >> + ? ? } >>> >> +done: >>> >> + ? ? range->len = (trimmed * sbi->sec_per_clus) << sb->s_blocksize_bits; >>> >> + ? ? fatent_brelse(&fatent); >>> >> +out: >>> >> + ? ? unlock_fat(sbi); >>> >> + ? ? return err; >>> >> +} >>> >> diff --git a/fs/fat/file.c b/fs/fat/file.c >>> >> index 7257752..9910aba 100644 >>> >> --- a/fs/fat/file.c >>> >> +++ b/fs/fat/file.c >>> >> @@ -125,6 +125,36 @@ long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) >>> >> ? ? ? ? ? ? ? return fat_ioctl_get_attributes(inode, user_attr); >>> >> ? ? ? case FAT_IOCTL_SET_ATTRIBUTES: >>> >> ? ? ? ? ? ? ? return fat_ioctl_set_attributes(filp, user_attr); >>> >> + ? ? case FITRIM: >>> >> + ? ? { >>> >> + ? ? ? ? ? ? struct super_block *sb = inode->i_sb; >>> >> + ? ? ? ? ? ? struct request_queue *q = bdev_get_queue(sb->s_bdev); >>> >> + ? ? ? ? ? ? struct fstrim_range range; >>> >> + ? ? ? ? ? ? int ret = 0; >>> >> + >>> >> + ? ? ? ? ? ? if (!capable(CAP_SYS_ADMIN)) >>> >> + ? ? ? ? ? ? ? ? ? ? return -EPERM; >>> >> + >>> >> + ? ? ? ? ? ? if (!blk_queue_discard(q)) >>> >> + ? ? ? ? ? ? ? ? ? ? return -EOPNOTSUPP; >>> >> + >>> >> + ? ? ? ? ? ? if (copy_from_user(&range, (struct fstrim_range *)arg, >>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? sizeof(range))) >>> >> + ? ? ? ? ? ? ? ? ? ? return -EFAULT; >>> >> + >>> >> + ? ? ? ? ? ? range.minlen = max((unsigned int)range.minlen, >>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? q->limits.discard_granularity); >>> >> + ? ? ? ? ? ? ret = fat_trim_fs(sb, &range); >>> >> + ? ? ? ? ? ? if (ret < 0) >>> >> + ? ? ? ? ? ? ? ? ? ? return ret; >>> >> + >>> >> + ? ? ? ? ? ? if (copy_to_user((struct fstrim_range *)arg, &range, >>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? sizeof(range))) >>> >> + ? ? ? ? ? ? ? ? ? ? return -EFAULT; >>> >> + >>> >> + ? ? ? ? ? ? return 0; >>> >> + ? ? } >>> >> + >>> >> ? ? ? default: >>> >> ? ? ? ? ? ? ? return -ENOTTY; /* Inappropriate ioctl for device */ >>> >> ? ? ? } >>> >> >>> > >>> > -- >>> > >>> >> >> -- > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/