From b1c57c1caa753cec299e62bb4272da0e85a01ef0 Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Wed, 8 Jan 2014 13:45:08 +0900 Subject: [PATCH] f2fs: add a sysfs entry to control max_victim_search Previously during SSR and GC, the maximum number of retrials to find a victim segment was hard-coded by MAX_VICTIM_SEARCH, 4096 by default. This number makes an effect on IO locality, when SSR mode is activated, which results in performance fluctuation on some low-end devices. If max_victim_search = 4, the victim will be searched like below. ("D" represents a dirty segment, and "*" indicates a selected victim segment.) D1 D2 D3 D4 D5 D6 D7 D8 D9 [ * ] [ * ] [ * ] [ ....] This patch adds a sysfs entry to control the number dynamically through: /sys/fs/f2fs/$dev/max_victim_search Signed-off-by: Jaegeuk Kim --- fs/f2fs/f2fs.h | 3 +++ fs/f2fs/gc.c | 4 ++-- fs/f2fs/gc.h | 2 +- fs/f2fs/super.c | 6 ++++++ 4 files changed, 12 insertions(+), 3 deletions(-) diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index b69f190fb195..5f7dc4f6eb09 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -451,6 +451,9 @@ struct f2fs_sb_info { struct f2fs_gc_kthread *gc_thread; /* GC thread */ unsigned int cur_victim_sec; /* current victim section num */ + /* maximum # of trials to find a victim segment for SSR and GC */ + unsigned int max_victim_search; + /* * for stat information. * one is for the LFS mode, and the other is for the SSR mode. diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c index 599f546d042c..9117ccaf254a 100644 --- a/fs/f2fs/gc.c +++ b/fs/f2fs/gc.c @@ -163,8 +163,8 @@ static void select_policy(struct f2fs_sb_info *sbi, int gc_type, p->ofs_unit = sbi->segs_per_sec; } - if (p->max_search > MAX_VICTIM_SEARCH) - p->max_search = MAX_VICTIM_SEARCH; + if (p->max_search > sbi->max_victim_search) + p->max_search = sbi->max_victim_search; p->offset = sbi->last_victim[p->gc_mode]; } diff --git a/fs/f2fs/gc.h b/fs/f2fs/gc.h index 507056d22205..5d5eb6047bf4 100644 --- a/fs/f2fs/gc.h +++ b/fs/f2fs/gc.h @@ -20,7 +20,7 @@ #define LIMIT_FREE_BLOCK 40 /* percentage over invalid + free space */ /* Search max. number of dirty segments to select a victim segment */ -#define MAX_VICTIM_SEARCH 4096 /* covers 8GB */ +#define DEF_MAX_VICTIM_SEARCH 4096 /* covers 8GB */ struct f2fs_gc_kthread { struct task_struct *f2fs_gc_task; diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index f16da92a7899..b070f3010ce9 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -74,6 +74,7 @@ static match_table_t f2fs_tokens = { enum { GC_THREAD, /* struct f2fs_gc_thread */ SM_INFO, /* struct f2fs_sm_info */ + F2FS_SBI, /* struct f2fs_sb_info */ }; struct f2fs_attr { @@ -91,6 +92,8 @@ static unsigned char *__struct_ptr(struct f2fs_sb_info *sbi, int struct_type) return (unsigned char *)sbi->gc_thread; else if (struct_type == SM_INFO) return (unsigned char *)SM_I(sbi); + else if (struct_type == F2FS_SBI) + return (unsigned char *)sbi; return NULL; } @@ -180,6 +183,7 @@ F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, reclaim_segments, rec_prefree_segments); F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, max_small_discards, max_discards); F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, ipu_policy, ipu_policy); F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, min_ipu_util, min_ipu_util); +F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, max_victim_search, max_victim_search); #define ATTR_LIST(name) (&f2fs_attr_##name.attr) static struct attribute *f2fs_attrs[] = { @@ -191,6 +195,7 @@ static struct attribute *f2fs_attrs[] = { ATTR_LIST(max_small_discards), ATTR_LIST(ipu_policy), ATTR_LIST(min_ipu_util), + ATTR_LIST(max_victim_search), NULL, }; @@ -775,6 +780,7 @@ static void init_sb_info(struct f2fs_sb_info *sbi) sbi->node_ino_num = le32_to_cpu(raw_super->node_ino); sbi->meta_ino_num = le32_to_cpu(raw_super->meta_ino); sbi->cur_victim_sec = NULL_SECNO; + sbi->max_victim_search = DEF_MAX_VICTIM_SEARCH; for (i = 0; i < NR_COUNT_TYPE; i++) atomic_set(&sbi->nr_pages[i], 0); -- 2.30.2