On 03/12/2014 09:40 PM, Jens Axboe wrote:
On 2014-03-12 11:35, Sagi Grimberg wrote:
Hey Jens,
So I'm looking at blk_iopoll for iSER & SRP and I have one gap I would
like to get your input on.
In blk-iopoll.c I see:
int blk_iopoll_enabled = 1;
EXPORT_SYMBOL(blk_iopoll_enabled);
This is set to 1 and exported for everyone to condition and *modify* it.
The documentation says the user must check this when using blk_iopoll.
My question is why? it should always be true shouldn't it?
Moreover, isn't it better to protect it using a get() function of it?
can't someone set it to 0 and shutdown the lights on everyone else?
We can kill it. IIRC, it was mostly used during development to test
functionality and performance (and wired to a sysfs toggle file).
But... Just because it's exported doesn't mean that random users are
allowed to just disable it. What's left now is an always-on, so we can
remove it.
It _is_ still exported, I just forgot it was put in sysctl. I'll kill it
off completely now. It's safe to toggle from user space, but only
practically so if IO is idle. It makes no attempt to ensure that, as it
was just a debug thing.
--
Jens Axboe
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