Re: [PATCH 04/39] ocfs2: track local alloc state via debugfs

Andrew Morton
2008-10-02T06:13:06Z

> On Wed, 24 Sep 2008 15:00:45 -0700 Mark Fasheh <mfasheh@suse.com> wrote:
> A per-mount debugfs file, "local_alloc" is created which when read will
> expose live state of the nodes local alloc file. Performance impact is
> minimal, only a bit of memory overhead per mount point. Still, the code is
> hidden behind CONFIG_OCFS2_FS_STATS. This feature will help us debug
> local alloc performance problems on a live system.
>
> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
> ---
> fs/ocfs2/localalloc.c | 87 +++++++++++++++++++++++++++++++++++++++++++++++++
> fs/ocfs2/ocfs2.h | 5 +++
> 2 files changed, 92 insertions(+), 0 deletions(-)
>
> diff --git a/fs/ocfs2/localalloc.c b/fs/ocfs2/localalloc.c
> index f71658a..b889f10 100644
> --- a/fs/ocfs2/localalloc.c
> +++ b/fs/ocfs2/localalloc.c
> @@ -28,6 +28,7 @@
> #include <linux/slab.h>
> #include <linux/highmem.h>
> #include <linux/bitops.h>
> +#include <linux/debugfs.h>
>
> #define MLOG_MASK_PREFIX ML_DISK_ALLOC
> #include <cluster/masklog.h>
> @@ -73,6 +74,85 @@ static int ocfs2_local_alloc_new_window(struct ocfs2_super *osb,
> static int ocfs2_local_alloc_slide_window(struct ocfs2_super *osb,
> struct inode *local_alloc_inode);
>
> +#ifdef CONFIG_OCFS2_FS_STATS
> +
> +DEFINE_MUTEX(la_debug_mutex);

Unless this mutex is used in a later patch, it can be made static to this file.

> +static int ocfs2_la_debug_open(struct inode *inode, struct file *file)
> +{
> + file->private_data = inode->i_private;
> + return 0;
> +}
> +
> +#define LA_DEBUG_BUF_SZ PAGE_CACHE_SIZE
> +#define LA_DEBUG_VER 1
> +static ssize_t ocfs2_la_debug_read(struct file *file, char __user *userbuf,
> + size_t count, loff_t *ppos)
> +{
> + struct ocfs2_super *osb = file->private_data;
> + int written, ret;
> + char *buf = osb->local_alloc_debug_buf;
> +
> + mutex_lock(&la_debug_mutex);
> + memset(buf, 0, LA_DEBUG_BUF_SZ);
> +
> + written = snprintf(buf, LA_DEBUG_BUF_SZ,
> + "0x%x\t0x%llx\t%u\t%u\t0x%x\n",
> + LA_DEBUG_VER,
> + (unsigned long long)osb->la_last_gd,
> + osb->local_alloc_default_bits,
> + osb->local_alloc_bits, osb->local_alloc_state);
> +
> + ret = simple_read_from_buffer(userbuf, count, ppos, buf, written);
> +
> + mutex_unlock(&la_debug_mutex);
> + return ret;
> +}

In fact it can be made static and local to this function.

> +static const struct file_operations ocfs2_la_debug_fops = {
> + .open = ocfs2_la_debug_open,
> + .read = ocfs2_la_debug_read,
> +};
> +
> +static void ocfs2_init_la_debug(struct ocfs2_super *osb)
> +{
> + osb->local_alloc_debug_buf = kmalloc(LA_DEBUG_BUF_SZ, GFP_NOFS);
> + if (!osb->local_alloc_debug_buf)
> + return;
> +
> + osb->local_alloc_debug = debugfs_create_file("local_alloc_stats",
> + S_IFREG|S_IRUSR,
> + osb->osb_debug_root,
> + osb,
> + &ocfs2_la_debug_fops);
> + if (!osb->local_alloc_debug) {
> + kfree(osb->local_alloc_debug_buf);
> + osb->local_alloc_debug_buf = NULL;
> + }
> +}
> +
> +static void ocfs2_shutdown_la_debug(struct ocfs2_super *osb)
> +{
> + if (osb->local_alloc_debug)
> + debugfs_remove(osb->local_alloc_debug);
> +
> + if (osb->local_alloc_debug_buf)
> + kfree(osb->local_alloc_debug_buf);
> +
> + osb->local_alloc_debug_buf = NULL;
> + osb->local_alloc_debug = NULL;
> +}
> +#else /* CONFIG_OCFS2_FS_STATS */
> +static void ocfs2_init_la_debug(struct ocfs2_super *osb)
> +{
> + return;
> +}
> +static void ocfs2_shutdown_la_debug(struct ocfs2_super *osb)
> +{
> + return;
> +}
> +#endif
> +
> static inline int ocfs2_la_state_enabled(struct ocfs2_super *osb)
> {
> return (osb->local_alloc_state == OCFS2_LA_THROTTLED ||
> @@ -146,6 +226,8 @@ int ocfs2_load_local_alloc(struct ocfs2_super *osb)
>
> mlog_entry_void();
>
> + ocfs2_init_la_debug(osb);
> +
> if (osb->local_alloc_bits == 0)
> goto bail;
>
> @@ -218,6 +300,9 @@ bail:
> if (inode)
> iput(inode);
>
> + if (status < 0)
> + ocfs2_shutdown_la_debug(osb);
> +
> mlog(0, "Local alloc window bits = %d\n", osb->local_alloc_bits);
>
> mlog_exit(status);
> @@ -247,6 +332,8 @@ void ocfs2_shutdown_local_alloc(struct ocfs2_super *osb)
> cancel_delayed_work(&osb->la_enable_wq);
> flush_workqueue(ocfs2_wq);
>
> + ocfs2_shutdown_la_debug(osb);
> +
> if (osb->local_alloc_state == OCFS2_LA_UNUSED)
> goto out;
>
> diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
> index 4d6e200..1282799 100644
> --- a/fs/ocfs2/ocfs2.h
> +++ b/fs/ocfs2/ocfs2.h
> @@ -272,6 +272,11 @@ struct ocfs2_super
>
> u64 la_last_gd;
>
> +#ifdef CONFIG_OCFS2_FS_STATS
> + struct dentry *local_alloc_debug;
> + char *local_alloc_debug_buf;
> +#endif
> +
> /* Next two fields are for local node slot recovery during
> * mount. */
> int dirty;
> --
> 1.5.4.5
>
> --
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