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Message-ID: <448ec877-7486-c02b-e6ba-3c32aafff9bf@kernel.org>
Date: Tue, 3 Aug 2021 10:42:08 +0800
From: Chao Yu <chao@...nel.org>
To: Daeho Jeong <daeho43@...il.com>, linux-kernel@...r.kernel.org,
linux-f2fs-devel@...ts.sourceforge.net, kernel-team@...roid.com
Cc: Jaegeuk Kim <jaegeuk@...nel.org>,
Daeho Jeong <daehojeong@...gle.com>
Subject: Re: [f2fs-dev] [PATCH v2] f2fs: add sysfs node to control ra_pages
for fadvise seq file
On 2021/8/3 1:57, Daeho Jeong wrote:
> From: Daeho Jeong <daehojeong@...gle.com>
>
> fadvise() allows the user to expand the readahead window to double with
> POSIX_FADV_SEQUENTIAL, now. But, in some use cases, it is not that
> sufficient and we need to meet the need in a restricted way. We can
> control the multiplier value of bdi device readahead between 2 (default)
> and 256 for POSIX_FADV_SEQUENTIAL advise option.
>
> Signed-off-by: Daeho Jeong <daehojeong@...gle.com>
> Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
>
> ---
> v2: fix minor style issues
> ---
> Documentation/ABI/testing/sysfs-fs-f2fs | 6 +++++
> fs/f2fs/f2fs.h | 2 ++
> fs/f2fs/file.c | 30 +++++++++++++++++++++++++
> fs/f2fs/super.c | 1 +
> fs/f2fs/sysfs.c | 13 +++++++++++
> 5 files changed, 52 insertions(+)
>
> diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
> index 845c4be535b0..73211f77d11e 100644
> --- a/Documentation/ABI/testing/sysfs-fs-f2fs
> +++ b/Documentation/ABI/testing/sysfs-fs-f2fs
> @@ -507,3 +507,9 @@ Date: July 2021
> Contact: "Daeho Jeong" <daehojeong@...gle.com>
> Description: You can control for which gc mode the "gc_reclaimed_segments" node shows.
> Refer to the description of the modes in "gc_reclaimed_segments".
> +
> +What: /sys/fs/f2fs/<disk>/seq_file_ra_mul
> +Date: July 2021
> +Contact: "Daeho Jeong" <daehojeong@...gle.com>
> +Description: You can control the multiplier value of bdi device readahead window size
> + between 2 (default) and 256 for POSIX_FADV_SEQUENTIAL advise option.
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 8459b6d5a2f8..5d16486feb8f 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1738,6 +1738,8 @@ struct f2fs_sb_info {
> unsigned int gc_segment_mode; /* GC state for reclaimed segments */
> unsigned int gc_reclaimed_segs[MAX_GC_MODE]; /* Reclaimed segs for each mode */
>
> + unsigned long seq_file_ra_mul; /* multiplier for ra_pages of seq. files in fadvise */
> +
> #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 */
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index b1cb5b50faac..1a631e6d3e9b 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -23,6 +23,7 @@
> #include <linux/nls.h>
> #include <linux/sched/signal.h>
> #include <linux/fileattr.h>
> +#include <linux/fadvise.h>
>
> #include "f2fs.h"
> #include "node.h"
> @@ -4332,6 +4333,34 @@ static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
> return ret;
> }
>
> +static int f2fs_file_fadvise(struct file *filp, loff_t offset, loff_t len,
> + int advice)
> +{
> + struct inode *inode;
> + struct address_space *mapping;
> + struct backing_dev_info *bdi;
> +
> + if (advice == POSIX_FADV_SEQUENTIAL) {
> + inode = file_inode(filp);
> + if (S_ISFIFO(inode->i_mode))
> + return -ESPIPE;
> +
> + mapping = filp->f_mapping;
> + if (!mapping || len < 0)
> + return -EINVAL;
> +
> + bdi = inode_to_bdi(mapping->host);
> + filp->f_ra.ra_pages = bdi->ra_pages *
> + F2FS_I_SB(inode)->seq_file_ra_mul;
> + spin_lock(&filp->f_lock);
> + filp->f_mode &= ~FMODE_RANDOM;
> + spin_unlock(&filp->f_lock);
> + return 0;
> + }
> +
> + return generic_fadvise(filp, offset, len, advice);
> +}
> +
> #ifdef CONFIG_COMPAT
> struct compat_f2fs_gc_range {
> u32 sync;
> @@ -4460,4 +4489,5 @@ const struct file_operations f2fs_file_operations = {
> #endif
> .splice_read = generic_file_splice_read,
> .splice_write = iter_file_splice_write,
> + .fadvise = f2fs_file_fadvise,
> };
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index 72eb9d70969f..41765e90caa2 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -3422,6 +3422,7 @@ static void init_sb_info(struct f2fs_sb_info *sbi)
> sbi->next_victim_seg[FG_GC] = NULL_SEGNO;
> sbi->max_victim_search = DEF_MAX_VICTIM_SEARCH;
> sbi->migration_granularity = sbi->segs_per_sec;
> + sbi->seq_file_ra_mul = 2;
sbi->seq_file_ra_mul = MIN_RA_MUL;
Otherwise, it looks good to me.
Reviewed-by: Chao Yu <chao@...nel.org>
Thanks,
>
> 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 b1725620c07d..44b086e5b607 100644
> --- a/fs/f2fs/sysfs.c
> +++ b/fs/f2fs/sysfs.c
> @@ -50,6 +50,9 @@ struct f2fs_attr {
> int id;
> };
>
> +#define MIN_RA_MUL 2
> +#define MAX_RA_MUL 256
> +
> static ssize_t f2fs_sbi_show(struct f2fs_attr *a,
> struct f2fs_sb_info *sbi, char *buf);
>
> @@ -538,6 +541,14 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
> return count;
> }
>
> + if (!strcmp(a->attr.name, "seq_file_ra_mul")) {
> + if (t >= MIN_RA_MUL && t <= MAX_RA_MUL)
> + sbi->seq_file_ra_mul = t;
> + else
> + return -EINVAL;
> + return count;
> + }
> +
> *ui = (unsigned int)t;
>
> return count;
> @@ -763,6 +774,7 @@ F2FS_RW_ATTR(ATGC_INFO, atgc_management, atgc_candidate_count, max_candidate_cou
> F2FS_RW_ATTR(ATGC_INFO, atgc_management, atgc_age_weight, age_weight);
> 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);
>
> @@ -838,6 +850,7 @@ static struct attribute *f2fs_attrs[] = {
> ATTR_LIST(atgc_candidate_count),
> ATTR_LIST(atgc_age_weight),
> ATTR_LIST(atgc_age_threshold),
> + ATTR_LIST(seq_file_ra_mul),
> ATTR_LIST(gc_segment_mode),
> ATTR_LIST(gc_reclaimed_segments),
> NULL,
>
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