Re: [PATCH 2/6] kill-the-BKL/reiserfs: release the write lockbefore rescheduling on do_journal_end()

From: Ingo Molnar
Date: Fri May 01 2009 - 03:09:31 EST



* Frederic Weisbecker <fweisbec@xxxxxxxxx> wrote:

> When do_journal_end() copies data to the journal blocks buffers in memory,
> it reschedules if needed between each block copied and dirtyfied.
>
> We can also release the write lock at this rescheduling stage,
> like did the bkl implicitly.
>
> [ Impact: release the reiserfs write lock when it is not needed ]
>
> Cc: Jeff Mahoney <jeffm@xxxxxxxx>
> Cc: Chris Mason <chris.mason@xxxxxxxxxx>
> Cc: Alexander Beregalov <a.beregalov@xxxxxxxxx>
> Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
> ---
> fs/reiserfs/journal.c | 2 ++
> 1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c
> index 7976d7d..373d080 100644
> --- a/fs/reiserfs/journal.c
> +++ b/fs/reiserfs/journal.c
> @@ -4232,7 +4232,9 @@ static int do_journal_end(struct reiserfs_transaction_handle *th,
> next = cn->next;
> free_cnode(sb, cn);
> cn = next;
> + reiserfs_write_unlock(sb);
> cond_resched();
> + reiserfs_write_lock(sb);

There's 8 cond_resched()'s in the code - i'd suggest to introduce a
helper for this - reiserfs_write_cond_resched(sb) or so?

Ingo
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