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Commit f4033903 authored by Curt Wohlgemuth's avatar Curt Wohlgemuth Committed by Theodore Ts'o
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ext4: Make the length of the mb_history file tunable 



In memory-constrained systems with many partitions, the ~68K for each
partition for the mb_history buffer can be excessive.

This patch adds a new mount option, mb_history_length, as well as a
way of setting the default via a module parameter (or via a sysfs
parameter in /sys/module/ext4/parameter/default_mb_history_length).
If the mb_history_length is set to zero, the mb_history facility is
disabled entirely.

Signed-off-by: default avatarCurt Wohlgemuth <curtw@google.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent bb23c20a

fs/ext4/mballoc.c

+7 −6
Original line number Diff line number Diff line
@@ -2413,6 +2413,7 @@ static void ext4_mb_history_release(struct super_block *sb) 


	if (sbi->s_proc != NULL) {

		remove_proc_entry("mb_groups", sbi->s_proc);

		if (sbi->s_mb_history_max)

			remove_proc_entry("mb_history", sbi->s_proc);

	}

	kfree(sbi->s_mb_history);
@@ -2424,17 +2425,17 @@ static void ext4_mb_history_init(struct super_block *sb) 
	int i;



	if (sbi->s_proc != NULL) {

		if (sbi->s_mb_history_max)

			proc_create_data("mb_history", S_IRUGO, sbi->s_proc,

					 &ext4_mb_seq_history_fops, sb);

		proc_create_data("mb_groups", S_IRUGO, sbi->s_proc,

				 &ext4_mb_seq_groups_fops, sb);

	}



	sbi->s_mb_history_max = 1000;

	sbi->s_mb_history_cur = 0;

	spin_lock_init(&sbi->s_mb_history_lock);

	i = sbi->s_mb_history_max * sizeof(struct ext4_mb_history);

	sbi->s_mb_history = kzalloc(i, GFP_KERNEL);

	sbi->s_mb_history = i ? kzalloc(i, GFP_KERNEL) : NULL;

	/* if we can't allocate history, then we simple won't use it */

}
@@ -2444,7 +2445,7 @@ ext4_mb_store_history(struct ext4_allocation_context *ac) 
	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);

	struct ext4_mb_history h;



	if (unlikely(sbi->s_mb_history == NULL))

	if (sbi->s_mb_history == NULL)

		return;



	if (!(ac->ac_op & sbi->s_mb_history_filter))

fs/ext4/super.c

+17 −1
Original line number Diff line number Diff line
@@ -47,6 +47,13 @@ 
#include "xattr.h"

#include "acl.h"



static int default_mb_history_length = 1000;



module_param_named(default_mb_history_length, default_mb_history_length,

		   int, 0644);

MODULE_PARM_DESC(default_mb_history_length,

		 "Default number of entries saved for mb_history");



struct proc_dir_entry *ext4_proc_root;

static struct kset *ext4_kset;
@@ -1042,7 +1049,7 @@ enum { 
	Opt_journal_update, Opt_journal_dev,

	Opt_journal_checksum, Opt_journal_async_commit,

	Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,

	Opt_data_err_abort, Opt_data_err_ignore,

	Opt_data_err_abort, Opt_data_err_ignore, Opt_mb_history_length,

	Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,

	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_quota, Opt_noquota,

	Opt_ignore, Opt_barrier, Opt_nobarrier, Opt_err, Opt_resize,
@@ -1088,6 +1095,7 @@ static const match_table_t tokens = { 
	{Opt_data_writeback, "data=writeback"},

	{Opt_data_err_abort, "data_err=abort"},

	{Opt_data_err_ignore, "data_err=ignore"},

	{Opt_mb_history_length, "mb_history_length=%u"},

	{Opt_offusrjquota, "usrjquota="},

	{Opt_usrjquota, "usrjquota=%s"},

	{Opt_offgrpjquota, "grpjquota="},
@@ -1329,6 +1337,13 @@ static int parse_options(char *options, struct super_block *sb, 
		case Opt_data_err_ignore:

			clear_opt(sbi->s_mount_opt, DATA_ERR_ABORT);

			break;

		case Opt_mb_history_length:

			if (match_int(&args[0], &option))

				return 0;

			if (option < 0)

				return 0;

			sbi->s_mb_history_max = option;

			break;

#ifdef CONFIG_QUOTA

		case Opt_usrjquota:

			qtype = USRQUOTA;
@@ -2345,6 +2360,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) 
	sbi->s_commit_interval = JBD2_DEFAULT_MAX_COMMIT_AGE * HZ;

	sbi->s_min_batch_time = EXT4_DEF_MIN_BATCH_TIME;

	sbi->s_max_batch_time = EXT4_DEF_MAX_BATCH_TIME;

	sbi->s_mb_history_max = default_mb_history_length;



	set_opt(sbi->s_mount_opt, BARRIER);