On Thu, 7 Nov 2013 17:41:34 +0100, David Sterba wrote:
On Thu, Nov 07, 2013 at 01:51:53PM +0800, Qu Wenruo wrote:
@@ -753,6 +754,19 @@ struct btrfs_workqueue_struct *btrfs_alloc_workqueue(char
*name,
}
}
+ if (high_name) {
+ ret->high_wq = alloc_workqueue(high_name,
+ flags | WQ_HIGHPRI,
+ max_active);
I'd really like to add the btrfs- prefix of the workqueue. Quoting our
previous discussion:
Sorry, I forgot to add the "btrfs-" prefix.
But on the other hand, I prefer to add the prefix outside the
alloc_btrfs_workqueue,
which means change the strings passed to alloc_btrfs_workqueue.
(Maybe add a small macro?)
Which way do you prefer?
* the thread names lost the btrfs- prefix, this makes it hard to
identify the processes and we want this, either debugging or
performance monitoring
Yes, that's right.
But the problem is, even I added "btrfs-" prefix to the wq,
the real work executor is kernel workers without any prefix.
Still hard to debugging due to the workqueue mechanism.
AFAICS the string passed down to alloc_workqueue ends up in the process
name, this is what I'm expecing and don't understand what do you mean.
david
Sorry for the misunderstanding words.
What I mean is that, since we use the kernel workqueue,
there will be no kthread named the "btrfs-worker" or something like it.
(Only when WQ_MEM_RECLAIM is set, the rescuer kthread will have the name,
See kernel/workqueue.c if(flags & WQ_MEM_RECLAIM) para).
The real executor will be something like kworker/u8:6(Unbound workqueue),
so even the prefix is added, it's still harder than the original way to
debug
workqueue.
What makes it worse is that, to simulate the thresholding and ordering,
I added serveral helper functions, which even makes kernel tracing not so
meaningful(all function queued to workqueue will all be normal_helper or
ordered_helper).
Neither way, the prefix will be added, but I consider this may not really
help to debug or monitor.
Qu.
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Qu Wenruo
Development Dept.I
Nanjing Fujitsu Nanda Software Tech. Co., Ltd.(FNST)
No. 6 Wenzhu Road, Nanjing, 210012, China
TEL: +86+25-86630566-8526
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MAIL: quwen...@cn.fujitsu.com
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