diff options
| author |   Theodore Ts'o <tytso@mit.edu> | 2017-11-08 22:23:20 -0500 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2017-11-08 22:23:20 -0500 |
| commit | 232530680290ba94ca37852ab10d9556ea28badf (patch) | |
| tree | cf23ba2b6c563adc685f3b9fee830ac7d202546c /fs/ext4 | |
| parent | ext4: add support for online resizing with bigalloc (diff) | |
| download | linux-dev-232530680290ba94ca37852ab10d9556ea28badf.tar.xz linux-dev-232530680290ba94ca37852ab10d9556ea28badf.zip | |
ext4: improve smp scalability for inode generation
->s_next_generation is protected by s_next_gen_lock but its usage
pattern is very primitive. We don't actually need sequentially
increasing new generation numbers, so let's use prandom_u32() instead.
Reported-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/ext4.h | 2 | ||||
| -rw-r--r-- | fs/ext4/ialloc.c | 4 | ||||
| -rw-r--r-- | fs/ext4/ioctl.c | 8 | ||||
| -rw-r--r-- | fs/ext4/super.c | 2 |
4 files changed, 4 insertions, 12 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 53ce95b52fd8..5e6d7b6f50c7 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1355,8 +1355,6 @@ struct ext4_sb_info { int s_first_ino; unsigned int s_inode_readahead_blks; unsigned int s_inode_goal; - spinlock_t s_next_gen_lock; - u32 s_next_generation; u32 s_hash_seed[4]; int s_def_hash_version; int s_hash_unsigned; /* 3 if hash should be signed, 0 if not */ diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c index ee823022aa34..da79eb5dba40 100644 --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -1138,9 +1138,7 @@ got: inode->i_ino); goto out; } - spin_lock(&sbi->s_next_gen_lock); - inode->i_generation = sbi->s_next_generation++; - spin_unlock(&sbi->s_next_gen_lock); + inode->i_generation = prandom_u32(); /* Precompute checksum seed for inode metadata */ if (ext4_has_metadata_csum(sb)) { diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index 144bbda2b808..23a4766f6678 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -14,6 +14,7 @@ #include <linux/mount.h> #include <linux/file.h> #include <linux/quotaops.h> +#include <linux/random.h> #include <linux/uuid.h> #include <linux/uaccess.h> #include <linux/delay.h> @@ -98,7 +99,6 @@ static long swap_inode_boot_loader(struct super_block *sb, int err; struct inode *inode_bl; struct ext4_inode_info *ei_bl; - struct ext4_sb_info *sbi = EXT4_SB(sb); if (inode->i_nlink != 1 || !S_ISREG(inode->i_mode)) return -EINVAL; @@ -157,10 +157,8 @@ static long swap_inode_boot_loader(struct super_block *sb, inode->i_ctime = inode_bl->i_ctime = current_time(inode); - spin_lock(&sbi->s_next_gen_lock); - inode->i_generation = sbi->s_next_generation++; - inode_bl->i_generation = sbi->s_next_generation++; - spin_unlock(&sbi->s_next_gen_lock); + inode->i_generation = prandom_u32(); + inode_bl->i_generation = prandom_u32(); ext4_discard_preallocations(inode); diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 3a278faf5868..9f2e3eb5131f 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -3982,8 +3982,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) } sbi->s_gdb_count = db_count; - get_random_bytes(&sbi->s_next_generation, sizeof(u32)); - spin_lock_init(&sbi->s_next_gen_lock); timer_setup(&sbi->s_err_report, print_daily_error_info, 0); |