From f40339031b04279c3fdde7ac5fe97db33b2a7694 Mon Sep 17 00:00:00 2001 From: Curt Wohlgemuth Date: Fri, 1 May 2009 20:27:20 -0400 Subject: 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: Curt Wohlgemuth Signed-off-by: "Theodore Ts'o" --- fs/ext4/super.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) (limited to 'fs/ext4/super.c') diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 7903f20c807..39223a52bc7 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -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); -- cgit v1.2.3-70-g09d2