From: Eric Sandeen Subject: Re: [PATCH, RFC -V2 1/4] ext4: Add configurable run-time mballoc debugging Date: Sun, 09 Aug 2009 22:42:17 -0500 Message-ID: <4A7F9719.1030209@redhat.com> References: <1249874635-24250-1-git-send-email-tytso@mit.edu> <1249874635-24250-2-git-send-email-tytso@mit.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org, Andreas Dilger , Alex Tomas To: "Theodore Ts'o" Return-path: Received: from mx2.redhat.com ([66.187.237.31]:60347 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753198AbZHJDmT (ORCPT ); Sun, 9 Aug 2009 23:42:19 -0400 In-Reply-To: <1249874635-24250-2-git-send-email-tytso@mit.edu> Sender: linux-ext4-owner@vger.kernel.org List-ID: Theodore Ts'o wrote: > Allow mballoc debugging to be enabled at run-time instead of just at > compile time. > > Signed-off-by: "Theodore Ts'o" > --- > fs/ext4/Kconfig | 9 ++++++ > fs/ext4/mballoc.c | 81 ++++++++++++++++++++++++++++++++++++++-------------- > fs/ext4/mballoc.h | 16 ++++++++-- > 3 files changed, 80 insertions(+), 26 deletions(-) This looks fine to me, though is there any reason to add the debug verbosity level at this point, when it's all just "1?" If you're going to do that I suppose I'd suggest some #defines that give an idea of the expected range... at least low/medium/high... will our debug go to 11? ;) -Eric > diff --git a/fs/ext4/Kconfig b/fs/ext4/Kconfig > index 1523046..d5c0ea2 100644 > --- a/fs/ext4/Kconfig > +++ b/fs/ext4/Kconfig > @@ -77,3 +77,12 @@ config EXT4_FS_SECURITY > > If you are not using a security module that requires using > extended attributes for file security labels, say N. > + > +config EXT4_DEBUG > + bool "EXT4 debugging support" > + depends on EXT4_FS > + help > + Enables run-time debugging support for the ext4 filesystem. > + > + If you select Y here, then you will be able to turn on debugging > + with a command such as "echo 1 > /sys/kernel/debug/ext4/mballoc-debug" > diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c > index 68cde59..2c81240 100644 > --- a/fs/ext4/mballoc.c > +++ b/fs/ext4/mballoc.c > @@ -22,6 +22,7 @@ > */ > > #include "mballoc.h" > +#include > #include > > /* > @@ -743,7 +744,7 @@ static int ext4_mb_init_cache(struct page *page, char *incore) > char *data; > char *bitmap; > > - mb_debug("init page %lu\n", page->index); > + mb_debug(1, "init page %lu\n", page->index); > > inode = page->mapping->host; > sb = inode->i_sb; > @@ -822,7 +823,7 @@ static int ext4_mb_init_cache(struct page *page, char *incore) > set_bitmap_uptodate(bh[i]); > bh[i]->b_end_io = end_buffer_read_sync; > submit_bh(READ, bh[i]); > - mb_debug("read bitmap for group %u\n", first_group + i); > + mb_debug(1, "read bitmap for group %u\n", first_group + i); > } > > /* wait for I/O completion */ > @@ -862,7 +863,7 @@ static int ext4_mb_init_cache(struct page *page, char *incore) > if ((first_block + i) & 1) { > /* this is block of buddy */ > BUG_ON(incore == NULL); > - mb_debug("put buddy for group %u in page %lu/%x\n", > + mb_debug(1, "put buddy for group %u in page %lu/%x\n", > group, page->index, i * blocksize); > grinfo = ext4_get_group_info(sb, group); > grinfo->bb_fragments = 0; > @@ -878,7 +879,7 @@ static int ext4_mb_init_cache(struct page *page, char *incore) > } else { > /* this is block of bitmap */ > BUG_ON(incore != NULL); > - mb_debug("put bitmap for group %u in page %lu/%x\n", > + mb_debug(1, "put bitmap for group %u in page %lu/%x\n", > group, page->index, i * blocksize); > > /* see comments in ext4_mb_put_pa() */ > @@ -922,7 +923,7 @@ ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group, > struct ext4_sb_info *sbi = EXT4_SB(sb); > struct inode *inode = sbi->s_buddy_cache; > > - mb_debug("load group %u\n", group); > + mb_debug(1, "load group %u\n", group); > > blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize; > grp = ext4_get_group_info(sb, group); > @@ -1851,7 +1852,7 @@ int ext4_mb_init_group(struct super_block *sb, ext4_group_t group) > struct inode *inode = sbi->s_buddy_cache; > struct page *page = NULL, *bitmap_page = NULL; > > - mb_debug("init group %u\n", group); > + mb_debug(1, "init group %u\n", group); > blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize; > this_grp = ext4_get_group_info(sb, group); > /* > @@ -2739,7 +2740,7 @@ static void ext4_mb_cleanup_pa(struct ext4_group_info *grp) > kmem_cache_free(ext4_pspace_cachep, pa); > } > if (count) > - mb_debug("mballoc: %u PAs left\n", count); > + mb_debug(1, "mballoc: %u PAs left\n", count); > > } > > @@ -2820,7 +2821,7 @@ static void release_blocks_on_commit(journal_t *journal, transaction_t *txn) > list_for_each_safe(l, ltmp, &txn->t_private_list) { > entry = list_entry(l, struct ext4_free_data, list); > > - mb_debug("gonna free %u blocks in group %u (0x%p):", > + mb_debug(1, "gonna free %u blocks in group %u (0x%p):", > entry->count, entry->group, entry); > > err = ext4_mb_load_buddy(sb, entry->group, &e4b); > @@ -2855,9 +2856,43 @@ static void release_blocks_on_commit(journal_t *journal, transaction_t *txn) > ext4_mb_release_desc(&e4b); > } > > - mb_debug("freed %u blocks in %u structures\n", count, count2); > + mb_debug(1, "freed %u blocks in %u structures\n", count, count2); > } > > +#ifdef CONFIG_EXT4_DEBUG > +u8 mb_enable_debug __read_mostly; > + > +static struct dentry *debugfs_dir; > +static struct dentry *debugfs_debug; > + > +static void __init ext4_create_debugfs_entry(void) > +{ > + debugfs_dir = debugfs_create_dir("ext4", NULL); > + if (debugfs_dir) > + debugfs_debug = debugfs_create_u8("mballoc-debug", > + S_IRUGO | S_IWUSR, > + debugfs_dir, > + &mb_enable_debug); > +} > + > +static void __exit ext4_remove_debugfs_entry(void) > +{ > + debugfs_remove(debugfs_debug); > + debugfs_remove(debugfs_dir); > +} > + > +#else > + > +static void __init ext4_create_debugfs_entry(void) > +{ > +} > + > +static void __exit ext4_remove_debugfs_entry(void) > +{ > +} > + > +#endif > + > int __init init_ext4_mballoc(void) > { > ext4_pspace_cachep = > @@ -2885,6 +2920,7 @@ int __init init_ext4_mballoc(void) > kmem_cache_destroy(ext4_ac_cachep); > return -ENOMEM; > } > + ext4_create_debugfs_entry(); > return 0; > } > > @@ -2898,6 +2934,7 @@ void exit_ext4_mballoc(void) > kmem_cache_destroy(ext4_pspace_cachep); > kmem_cache_destroy(ext4_ac_cachep); > kmem_cache_destroy(ext4_free_ext_cachep); > + ext4_remove_debugfs_entry(); > } > > > @@ -3042,7 +3079,7 @@ static void ext4_mb_normalize_group_request(struct ext4_allocation_context *ac) > ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_stripe; > else > ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_mb_group_prealloc; > - mb_debug("#%u: goal %u blocks for locality group\n", > + mb_debug(1, "#%u: goal %u blocks for locality group\n", > current->pid, ac->ac_g_ex.fe_len); > } > > @@ -3232,7 +3269,7 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac, > ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL; > } > > - mb_debug("goal: %u(was %u) blocks at %u\n", (unsigned) size, > + mb_debug(1, "goal: %u(was %u) blocks at %u\n", (unsigned) size, > (unsigned) orig_size, (unsigned) start); > } > > @@ -3281,7 +3318,7 @@ static void ext4_mb_use_inode_pa(struct ext4_allocation_context *ac, > BUG_ON(pa->pa_free < len); > pa->pa_free -= len; > > - mb_debug("use %llu/%u from inode pa %p\n", start, len, pa); > + mb_debug(1, "use %llu/%u from inode pa %p\n", start, len, pa); > } > > /* > @@ -3305,7 +3342,7 @@ static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac, > * in on-disk bitmap -- see ext4_mb_release_context() > * Other CPUs are prevented from allocating from this pa by lg_mutex > */ > - mb_debug("use %u/%u from group pa %p\n", pa->pa_lstart-len, len, pa); > + mb_debug(1, "use %u/%u from group pa %p\n", pa->pa_lstart-len, len, pa); > } > > /* > @@ -3484,7 +3521,7 @@ void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap, > preallocated += len; > count++; > } > - mb_debug("prellocated %u for group %u\n", preallocated, group); > + mb_debug(1, "prellocated %u for group %u\n", preallocated, group); > } > > static void ext4_mb_pa_callback(struct rcu_head *head) > @@ -3619,7 +3656,7 @@ ext4_mb_new_inode_pa(struct ext4_allocation_context *ac) > pa->pa_deleted = 0; > pa->pa_type = MB_INODE_PA; > > - mb_debug("new inode pa %p: %llu/%u for %u\n", pa, > + mb_debug(1, "new inode pa %p: %llu/%u for %u\n", pa, > pa->pa_pstart, pa->pa_len, pa->pa_lstart); > trace_ext4_mb_new_inode_pa(ac, pa); > > @@ -3679,7 +3716,7 @@ ext4_mb_new_group_pa(struct ext4_allocation_context *ac) > pa->pa_deleted = 0; > pa->pa_type = MB_GROUP_PA; > > - mb_debug("new group pa %p: %llu/%u for %u\n", pa, > + mb_debug(1, "new group pa %p: %llu/%u for %u\n", pa, > pa->pa_pstart, pa->pa_len, pa->pa_lstart); > trace_ext4_mb_new_group_pa(ac, pa); > > @@ -3758,7 +3795,7 @@ ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh, > next = mb_find_next_bit(bitmap_bh->b_data, end, bit); > start = group * EXT4_BLOCKS_PER_GROUP(sb) + bit + > le32_to_cpu(sbi->s_es->s_first_data_block); > - mb_debug(" free preallocated %u/%u in group %u\n", > + mb_debug(1, " free preallocated %u/%u in group %u\n", > (unsigned) start, (unsigned) next - bit, > (unsigned) group); > free += next - bit; > @@ -3849,7 +3886,7 @@ ext4_mb_discard_group_preallocations(struct super_block *sb, > int busy = 0; > int free = 0; > > - mb_debug("discard preallocation for group %u\n", group); > + mb_debug(1, "discard preallocation for group %u\n", group); > > if (list_empty(&grp->bb_prealloc_list)) > return 0; > @@ -3973,7 +4010,7 @@ void ext4_discard_preallocations(struct inode *inode) > return; > } > > - mb_debug("discard preallocation for inode %lu\n", inode->i_ino); > + mb_debug(1, "discard preallocation for inode %lu\n", inode->i_ino); > trace_ext4_discard_preallocations(inode); > > INIT_LIST_HEAD(&list); > @@ -4078,7 +4115,7 @@ static void ext4_mb_return_to_preallocation(struct inode *inode, > { > BUG_ON(!list_empty(&EXT4_I(inode)->i_prealloc_list)); > } > -#ifdef MB_DEBUG > +#ifdef CONFIG_EXT4_DEBUG > static void ext4_mb_show_ac(struct ext4_allocation_context *ac) > { > struct super_block *sb = ac->ac_sb; > @@ -4227,7 +4264,7 @@ ext4_mb_initialize_context(struct ext4_allocation_context *ac, > * locality group. this is a policy, actually */ > ext4_mb_group_or_file(ac); > > - mb_debug("init ac: %u blocks @ %u, goal %u, flags %x, 2^%d, " > + mb_debug(1, "init ac: %u blocks @ %u, goal %u, flags %x, 2^%d, " > "left: %u/%u, right %u/%u to %swritable\n", > (unsigned) ar->len, (unsigned) ar->logical, > (unsigned) ar->goal, ac->ac_flags, ac->ac_2order, > @@ -4249,7 +4286,7 @@ ext4_mb_discard_lg_preallocations(struct super_block *sb, > struct ext4_prealloc_space *pa, *tmp; > struct ext4_allocation_context *ac; > > - mb_debug("discard locality group preallocation\n"); > + mb_debug(1, "discard locality group preallocation\n"); > > INIT_LIST_HEAD(&discard_list); > ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS); > diff --git a/fs/ext4/mballoc.h b/fs/ext4/mballoc.h > index c96bb19..28abb02 100644 > --- a/fs/ext4/mballoc.h > +++ b/fs/ext4/mballoc.h > @@ -37,11 +37,19 @@ > > /* > */ > -#define MB_DEBUG__ > -#ifdef MB_DEBUG > -#define mb_debug(fmt, a...) printk(fmt, ##a) > +#ifdef CONFIG_EXT4_DEBUG > +extern u8 mb_enable_debug; > + > +#define mb_debug(n, fmt, a...) \ > + do { \ > + if ((n) <= mb_enable_debug) { \ > + printk (KERN_DEBUG "(%s, %d): %s: ", \ > + __FILE__, __LINE__, __func__); \ > + printk (fmt, ## a); \ > + } \ > + } while (0) > #else > -#define mb_debug(fmt, a...) > +#define mb_debug(n, fmt, a...) > #endif > > /*