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Date: Wed, 29 May 2019 02:12:08 -0600
From: "Gang He" <ghe@...e.com>
To: <jlbec@...lplan.org>, <mark@...heh.com>, <jiangqi903@...il.com>,
"Wengang" <wen.gang.wang@...cle.com>
Cc: <ocfs2-devel@....oracle.com>, <linux-kernel@...r.kernel.org>
Subject: Re: [Ocfs2-devel] [PATCH 1/2] ocfs2: add last unlock times in
locking_state
Hi Wengang,
>>> On 2019/5/29 at 1:22, in message
<66083663-1d25-437b-ce98-07d200f446ab@...cle.com>, Wengang
<wen.gang.wang@...cle.com> wrote:
> Hi Gang,
>
> This idea sounds cool!
> Some comments in lines:
>
> On 05/23/2019 03:40 AM, Gang He wrote:
>> ocfs2 file system uses locking_state file under debugfs to dump
>> each ocfs2 file system's dlm lock resources, but the dlm lock
>> resources in memory are becoming more and more after the files
>> were touched by the user. it will become a bit difficult to analyze
>> these dlm lock resource records in locking_state file by the upper
>> scripts, though some files are not active for now, which were
>> accessed long time ago.
>> Then, I'd like to add last pr/ex unlock times in locking_state file
>> for each dlm lock resource record, the the upper scripts can use
>> last unlock time to filter inactive dlm lock resource record.
>>
>> Signed-off-by: Gang He <ghe@...e.com>
>> Reviewed-by: Joseph Qi <joseph.qi@...ux.alibaba.com>
>> ---
>> fs/ocfs2/dlmglue.c | 21 +++++++++++++++++----
>> fs/ocfs2/ocfs2.h | 1 +
>> 2 files changed, 18 insertions(+), 4 deletions(-)
>>
>> diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
>> index af405586c5b1..dccf4136f8c1 100644
>> --- a/fs/ocfs2/dlmglue.c
>> +++ b/fs/ocfs2/dlmglue.c
>> @@ -448,7 +448,7 @@ static void ocfs2_update_lock_stats(struct
> ocfs2_lock_res *res, int level,
>> struct ocfs2_mask_waiter *mw, int ret)
>> {
>> u32 usec;
>> - ktime_t kt;
>> + ktime_t last, kt;
>> struct ocfs2_lock_stats *stats;
>>
>> if (level == LKM_PRMODE)
>> @@ -458,7 +458,8 @@ static void ocfs2_update_lock_stats(struct
> ocfs2_lock_res *res, int level,
>> else
>> return;
>>
>> - kt = ktime_sub(ktime_get(), mw->mw_lock_start);
>> + last = ktime_get();
> Will ktime_get_real() be better than ktime_get() here?
> Per description,
> ktime_get:
> Useful for reliable timestamps and measuring short time intervals
> accurately. Starts at system boot time but stops during suspend.
> ktime_get_real:
> Returns the time in relative to the UNIX epoch starting in 1970 using
> the Coordinated Universal Time (UTC), same as gettimeofday() user space.
>
> Since ktime_get() returnis time since boot time, this value is
> meaningless when compared to those from a different node in cluster, right?
Ok, maybe we can use ktime_get_real_seconds to get the seconds, but we
need to use 64bit time64_t type to save the value and dump to the user-space.
Thanks
Gang
>
> And we need a "__kernel_long_t" to rather than a "u32"?
>
>
>> + kt = ktime_sub(last, mw->mw_lock_start);
>> usec = ktime_to_us(kt);
>>
>> stats->ls_gets++;
>> @@ -474,6 +475,8 @@ static void ocfs2_update_lock_stats(struct
> ocfs2_lock_res *res, int level,
>>
>> if (ret)
>> stats->ls_fail++;
>> +
>> + stats->ls_last = ktime_to_timespec(last).tv_sec;
>> }
>>
> Though maybe ocfs2_update_lock_stats() is designed to be called for each
> successful lock request,
> seems current code calls it even when it returns with -EAGAIN which
> breaks the design. That's not introduced by your change, well, it may
> lead to wrong stats...
>
> thanks,
> wengang
>
>> static inline void ocfs2_track_lock_refresh(struct ocfs2_lock_res
> *lockres)
>> @@ -3093,8 +3096,10 @@ static void *ocfs2_dlm_seq_next(struct seq_file *m,
> void *v, loff_t *pos)
>> * - Lock stats printed
>> * New in version 3
>> * - Max time in lock stats is in usecs (instead of nsecs)
>> + * New in version 4
>> + * - Add last pr/ex unlock times in secs
>> */
>> -#define OCFS2_DLM_DEBUG_STR_VERSION 3
>> +#define OCFS2_DLM_DEBUG_STR_VERSION 4
>> static int ocfs2_dlm_seq_show(struct seq_file *m, void *v)
>> {
>> int i;
>> @@ -3145,6 +3150,8 @@ static int ocfs2_dlm_seq_show(struct seq_file *m, void
> *v)
>> # define lock_max_prmode(_l) ((_l)->l_lock_prmode.ls_max)
>> # define lock_max_exmode(_l) ((_l)->l_lock_exmode.ls_max)
>> # define lock_refresh(_l) ((_l)->l_lock_refresh)
>> +# define lock_last_prmode(_l) ((_l)->l_lock_prmode.ls_last)
>> +# define lock_last_exmode(_l) ((_l)->l_lock_exmode.ls_last)
>> #else
>> # define lock_num_prmode(_l) (0)
>> # define lock_num_exmode(_l) (0)
>> @@ -3155,6 +3162,8 @@ static int ocfs2_dlm_seq_show(struct seq_file *m, void
> *v)
>> # define lock_max_prmode(_l) (0)
>> # define lock_max_exmode(_l) (0)
>> # define lock_refresh(_l) (0)
>> +# define lock_last_prmode(_l) (0)
>> +# define lock_last_exmode(_l) (0)
>> #endif
>> /* The following seq_print was added in version 2 of this output */
>> seq_printf(m, "%u\t"
>> @@ -3165,6 +3174,8 @@ static int ocfs2_dlm_seq_show(struct seq_file *m, void
> *v)
>> "%llu\t"
>> "%u\t"
>> "%u\t"
>> + "%u\t"
>> + "%u\t"
>> "%u\t",
>> lock_num_prmode(lockres),
>> lock_num_exmode(lockres),
>> @@ -3174,7 +3185,9 @@ static int ocfs2_dlm_seq_show(struct seq_file *m, void
> *v)
>> lock_total_exmode(lockres),
>> lock_max_prmode(lockres),
>> lock_max_exmode(lockres),
>> - lock_refresh(lockres));
>> + lock_refresh(lockres),
>> + lock_last_prmode(lockres),
>> + lock_last_exmode(lockres));
>>
>> /* End the line */
>> seq_printf(m, "\n");
>> diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
>> index 1f029fbe8b8d..8efa022684f4 100644
>> --- a/fs/ocfs2/ocfs2.h
>> +++ b/fs/ocfs2/ocfs2.h
>> @@ -164,6 +164,7 @@ struct ocfs2_lock_stats {
>>
>> /* Storing max wait in usecs saves 24 bytes per inode */
>> u32 ls_max; /* Max wait in USEC */
>> + u32 ls_last; /* Last unlock time in SEC */
>> };
>> #endif
>>
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