From: amir73il@users.sourceforge.net Subject: [PATCH v1 26/36] ext4: snapshot journaled - trace COW/buffer credits Date: Tue, 7 Jun 2011 18:07:53 +0300 Message-ID: <1307459283-22130-27-git-send-email-amir73il@users.sourceforge.net> References: <1307459283-22130-1-git-send-email-amir73il@users.sourceforge.net> Cc: tytso@mit.edu, lczerner@redhat.com, Amir Goldstein , Yongqiang Yang To: linux-ext4@vger.kernel.org Return-path: Received: from mail-ww0-f44.google.com ([74.125.82.44]:41767 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753053Ab1FGPKI (ORCPT ); Tue, 7 Jun 2011 11:10:08 -0400 Received: by mail-ww0-f44.google.com with SMTP id 36so5035787wwa.1 for ; Tue, 07 Jun 2011 08:10:08 -0700 (PDT) In-Reply-To: <1307459283-22130-1-git-send-email-amir73il@users.sourceforge.net> Sender: linux-ext4-owner@vger.kernel.org List-ID: From: Amir Goldstein Extra debug prints to trace snapshot usage of buffer credits. Signed-off-by: Amir Goldstein Signed-off-by: Yongqiang Yang --- fs/ext4/ext4_jbd2.c | 80 +++++++++++++++++++++++++++++++++++++++++++++++++++ fs/ext4/ext4_jbd2.h | 26 ++++++++++++++++ fs/ext4/super.c | 2 + 3 files changed, 108 insertions(+), 0 deletions(-) diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c index e8287f4..eb88564 100644 --- a/fs/ext4/ext4_jbd2.c +++ b/fs/ext4/ext4_jbd2.c @@ -23,6 +23,7 @@ int __ext4_handle_get_bitmap_access(const char *where, unsigned int line, if (err) ext4_journal_abort_handle(where, line, __func__, bh, handle, err); + ext4_journal_trace(SNAP_DEBUG, where, handle, 1); } return err; } @@ -40,6 +41,7 @@ int __ext4_journal_get_write_access_inode(const char *where, unsigned int line, if (err) ext4_journal_abort_handle(where, line, __func__, bh, handle, err); + ext4_journal_trace(SNAP_DEBUG, where, handle, 1); } return err; } @@ -91,6 +93,7 @@ int __ext4_forget(const char *where, unsigned int line, handle_t *handle, if (err) ext4_journal_abort_handle(where, line, __func__, bh, handle, err); + ext4_journal_trace(SNAP_DEBUG, where, handle, 1); return err; } return 0; @@ -108,6 +111,7 @@ int __ext4_forget(const char *where, unsigned int line, handle_t *handle, "error %d when attempting revoke", err); } BUFFER_TRACE(bh, "exit"); + ext4_journal_trace(SNAP_DEBUG, where, handle, 1); return err; } @@ -123,6 +127,7 @@ int __ext4_journal_get_create_access(const char *where, unsigned int line, if (err) ext4_journal_abort_handle(where, line, __func__, bh, handle, err); + ext4_journal_trace(SNAP_DEBUG, where, handle, -1); } return err; } @@ -198,6 +203,7 @@ int __ext4_handle_dirty_metadata(const char *where, unsigned int line, } jbd_unlock_bh_state(bh); } + ext4_journal_trace(SNAP_DEBUG, where, handle, -1); } else { if (inode) mark_buffer_dirty_inode(bh, inode); @@ -236,3 +242,77 @@ int __ext4_handle_dirty_super(const char *where, unsigned int line, sb->s_dirt = 1; return err; } + +#ifdef CONFIG_JBD2_DEBUG +static void ext4_journal_cow_stats(int n, handle_t *handle) +{ + snapshot_debug(n, "COW stats: moved/copied=%d/%d, " + "mapped/bitmap/cached=%d/%d/%d, " + "bitmaps/cleared=%d/%d\n", handle->h_cow_moved, + handle->h_cow_copied, handle->h_cow_ok_mapped, + handle->h_cow_ok_bitmap, handle->h_cow_ok_jh, + handle->h_cow_bitmaps, handle->h_cow_excluded); +} +#else +#define ext4_journal_cow_stats(n, handle) +#endif + +#ifdef CONFIG_EXT4_DEBUG +void __ext4_journal_trace(int n, const char *fn, const char *caller, + handle_t *handle, int nblocks) +{ + int active_snapshot; + int upper; + int lower; + int final; + struct super_block *sb; + + sb = handle->h_transaction->t_journal->j_private; + if (!EXT4_SNAPSHOTS(sb)) + return; + + active_snapshot = ext4_snapshot_active(EXT4_SB(sb)); + upper = EXT4_SNAPSHOT_START_TRANS_BLOCKS(handle->h_base_credits); + lower = EXT4_SNAPSHOT_TRANS_BLOCKS(handle->h_user_credits); + final = (nblocks == 0 && handle->h_ref == 1 && + !IS_COWING(handle)); + + switch (snapshot_enable_debug) { + case SNAP_INFO: + /* trace final journal_stop if any credits have been used */ + if (final && (handle->h_buffer_credits < upper || + handle->h_user_credits < handle->h_base_credits)) + break; + case SNAP_WARN: + /* + * trace if buffer credits are too low - lower limit is only + * valid if there is an active snapshot and not during COW + */ + if (handle->h_buffer_credits < lower && + active_snapshot && !IS_COWING(handle)) + break; + case SNAP_ERR: + /* trace if user credits are too low */ + if (handle->h_user_credits < 0) + break; + case 0: + /* no trace */ + return; + + case SNAP_DEBUG: + default: + /* trace all calls */ + break; + } + + snapshot_debug_l(n, IS_COWING(handle), "%s(%d): credits=%d," + " limit=%d/%d, user=%d/%d, ref=%d, caller=%s\n", + fn, nblocks, handle->h_buffer_credits, lower, upper, + handle->h_user_credits, handle->h_base_credits, + handle->h_ref, caller); + if (!final) + return; + + ext4_journal_cow_stats(n, handle); +} +#endif diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h index cee6f2a..41951da 100644 --- a/fs/ext4/ext4_jbd2.h +++ b/fs/ext4/ext4_jbd2.h @@ -229,10 +229,36 @@ int __ext4_handle_dirty_super(const char *where, unsigned int line, #define ext4_handle_dirty_super(handle, sb) \ __ext4_handle_dirty_super(__func__, __LINE__, (handle), (sb)) +/* + * macros for ext4 to update transaction COW statistics. + * if the kernel was compiled without CONFIG_JBD2_DEBUG + * then the h_cow_* fields are not allocated in handle objects. + */ +#ifdef CONFIG_JBD2_DEBUG +#define trace_cow_add(handle, name, num) \ + (handle)->h_cow_##name += (num) +#define trace_cow_inc(handle, name) \ + (handle)->h_cow_##name++; + +#else #define trace_cow_add(handle, name, num) #define trace_cow_inc(handle, name) +#endif +#ifdef CONFIG_EXT4_DEBUG +void __ext4_journal_trace(int debug, const char *fn, const char *caller, + handle_t *handle, int nblocks); + +#define ext4_journal_trace(n, caller, handle, nblocks) \ + do { \ + if ((n) <= snapshot_enable_debug) \ + __ext4_journal_trace((n), __func__, (caller), \ + (handle), (nblocks)); \ + } while (0) + +#else #define ext4_journal_trace(n, caller, handle, nblocks) +#endif handle_t *__ext4_journal_start(const char *where, struct super_block *sb, int nblocks); diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 0d996be..fc8bfda 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -324,6 +324,8 @@ int __ext4_journal_stop(const char *where, unsigned int line, handle_t *handle) int err; int rc; + ext4_journal_trace(SNAP_WARN, where, handle, 0); + if (!ext4_handle_valid(handle)) { ext4_put_nojournal(handle); return 0; -- 1.7.4.1