Andrew Morton wrote:
> On Thu, 9 Jan 2014 21:52:00 +0900 Tetsuo Handa
> <penguin-ker...@i-love.sakura.ne.jp> wrote:
>
> > This patch introduces %pT format specifier for printing task_struct->comm.
> > Currently %pT does not provide consistency. I'm planning to change to use
> > RCU
> > in the future. By using RCU, the comm name read from task_struct->comm will
> > be
> > guaranteed to be consistent. But before modifying set_task_comm() to use
> > RCU,
> > we need to kill direct ->comm users who do not use get_task_comm().
>
> On reflection...
>
> It isn't obvious that this patch is sufficiently beneficial until we
> have that RCU code in place.
>
> So I could retain this patch in -mm until we have that all sorted out.
> And I'll have to avoid merging %pT users into mainline in the
> meanwhile!
>
> Am I wrong? The patch seems fairly pointless as a standalone thing?
>
Step 1: (targeted to 3.14-rc1)
Add "%pT" format specifier and commcpy() wrapper function.
Step 2: (started after step 1 is reflected to other git trees)
Replace printk("%s", p->comm) with printk("%pT", p).
Replace strcpy(buf, p->comm) with commcpy(buf, p).
Step 3: (started after step 2 is reflected to other git trees)
Add rcu_read_lock()/rcu_read_unlock() into commcpy().
Modify set_task_comm() etc. to replace ->comm using RCU.
This patch and commcpy() patch ( https://lkml.org/lkml/2014/1/10/217 ) are
targeted to be merged into 3.14-rc1. This is because we can start writing
patches to use "%pT" or commcpy() only after other git trees have rebased
using 3.14-rc1. After all direct ->comm readers are replaced to use "%pT" or
commcpy(), I can start ->comm modifying functions to use RCU.
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