Commit 0f6b56ec authored by Daeho Jeong's avatar Daeho Jeong Committed by Jaegeuk Kim
Browse files

f2fs: add sysfs node to control ra_pages for fadvise seq file 



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: default avatarDaeho Jeong <daehojeong@google.com>
Reviewed-by: default avatarChao Yu <chao@kernel.org>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 4f993264

Documentation/ABI/testing/sysfs-fs-f2fs

+6 −0
Original line number Diff line number Diff line
@@ -507,3 +507,9 @@ Date: July 2021 
Contact:	"Daeho Jeong" <daehojeong@google.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@google.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.

fs/f2fs/f2fs.h

+5 −0
Original line number Diff line number Diff line
@@ -1749,6 +1749,8 @@ 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 */
@@ -4003,6 +4005,9 @@ void f2fs_destroy_extent_cache(void); 
/*

 * sysfs.c

 */

#define MIN_RA_MUL	2

#define MAX_RA_MUL	256



int __init f2fs_init_sysfs(void);

void f2fs_exit_sysfs(void);

int f2fs_register_sysfs(struct f2fs_sb_info *sbi);

fs/f2fs/file.c

+30 −0
Original line number Diff line number Diff line
@@ -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"
@@ -4344,6 +4345,34 @@ 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;
@@ -4472,4 +4501,5 @@ const struct file_operations f2fs_file_operations = { 
#endif

	.splice_read	= generic_file_splice_read,

	.splice_write	= iter_file_splice_write,

	.fadvise	= f2fs_file_fadvise,

};

fs/f2fs/super.c

+1 −0
Original line number Diff line number Diff line
@@ -3466,6 +3466,7 @@ 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 = MIN_RA_MUL;



	sbi->dir_level = DEF_DIR_LEVEL;

	sbi->interval_time[CP_TIME] = DEF_CP_INTERVAL;

fs/f2fs/sysfs.c

+10 −0
Original line number Diff line number Diff line
@@ -540,6 +540,14 @@ 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;
@@ -765,6 +773,7 @@ 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);
@@ -840,6 +849,7 @@ 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,