Messages in this thread Patch in this message | | | Date | Sat, 15 Mar 2003 13:51:58 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] concurrent inode allocation for ext2 against 2.5.64 |
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Alex Tomas <bzzz@tmi.comex.ru> wrote: > > > hi! > > here is the patch for ext2 concurrent inode allocation. should be applied > on top of previous concurrent-balloc patch. tested on dual p3 for several > hours of stress-test + fsck. hope someone test it on big iron ;) >
> ... > +void ext2_reserve_inode (struct super_block * sb, int group, int dir) > +{
This can have static scope. And, please, no spaces after the function name, nor after the `*' thingy. ext2 is all over the place in this regard and I'm slowly trying to get it consistent.
I'm not sure that skipping setting s_dirt is desirable. Sure, we haven't actually altered the superblock. But we sort-of "virtually dirtied" it. The superblock is now out-of-date and we should sync it.
It could be that not writing the superblock for a week is an OK thing to do. inode and block allocation counts are something which fsck can trivially fix up. But at the cost of a single sector write per five seconds I think it's best to keep the superblock more up-to-date.
I'll make the same change to the block allocator patches.
> struct ext2_bg_info { > u8 debts; > spinlock_t balloc_lock; > + spinlock_t ialloc_lock; > unsigned int reserved; > } ____cacheline_aligned_in_smp; >
hm, I wonder if this should be in a separate cacheline. We may as well use a single lock if they're this close together. Bill, can you test that sometime?
diff -puN fs/ext2/ialloc.c~ext2-ialloc-no-lock_super-fixes fs/ext2/ialloc.c --- 25/fs/ext2/ialloc.c~ext2-ialloc-no-lock_super-fixes 2003-03-15 13:36:14.000000000 -0800 +++ 25-akpm/fs/ext2/ialloc.c 2003-03-15 13:40:43.000000000 -0800 @@ -63,7 +63,17 @@ error_out: return bh; } -void ext2_reserve_inode (struct super_block * sb, int group, int dir) +/* + * Speculatively reserve an inode in a blockgroup which used to have some + * spare ones. Later, when we come to actually claim the inode in the bitmap + * it may be that it was taken. In that case the allocator will undo this + * reservation and try again. + * + * The inode allocator does not physically alter the superblock. But we still + * set sb->s_dirt, because the superblock was "logically" altered - we need to + * go and add up the free inodes counts again and flush out the superblock. + */ +static void ext2_reserve_inode(struct super_block *sb, int group, int dir) { struct ext2_group_desc * desc; struct buffer_head *bh; @@ -72,7 +82,7 @@ void ext2_reserve_inode (struct super_bl if (!desc) { ext2_error(sb, "ext2_reserve_inode", "can't get descriptor for group %d", group); - return; + return; } spin_lock(&EXT2_SB(sb)->s_bgi[group].ialloc_lock); @@ -82,11 +92,11 @@ void ext2_reserve_inode (struct super_bl desc->bg_used_dirs_count = cpu_to_le16(le16_to_cpu(desc->bg_used_dirs_count) + 1); spin_unlock(&EXT2_SB(sb)->s_bgi[group].ialloc_lock); - + sb->s_dirt = 1; mark_buffer_dirty(bh); } -void ext2_release_inode (struct super_block * sb, int group, int dir) +static void ext2_release_inode(struct super_block *sb, int group, int dir) { struct ext2_group_desc * desc; struct buffer_head *bh; @@ -105,7 +115,7 @@ void ext2_release_inode (struct super_bl desc->bg_used_dirs_count = cpu_to_le16(le16_to_cpu(desc->bg_used_dirs_count) - 1); spin_unlock(&EXT2_SB(sb)->s_bgi[group].ialloc_lock); - + sb->s_dirt = 1; mark_buffer_dirty(bh); } _
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