From b1c57c1caa753cec299e62bb4272da0e85a01ef0 Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Wed, 8 Jan 2014 13:45:08 +0900 Subject: 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 +++ 1 file changed, 3 insertions(+) (limited to 'fs/f2fs/f2fs.h') 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. -- cgit v1.2.3