[lkml]   [1996]   [Nov]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: proc_generic - cool new stuff

On 07-Nov-96 wrote:
>>> therefore must be OK to sleep in. It definitely cannot use cli/sti
>> to lock it's tables. Anything still relying on cli/sti will need
>> to be cached. (And hopefully some of these will be fixed by Keith
>> Owens soon.)
>You mean like the routing tables. We cannot sleep in the routing handling
>end of story. The current code just builds a kernel buffer, unlocks and
>feeds that out. That should work fine with your changes

I don't understand. In my code, when operating in non-cached
mode, proc_write() is not buffered, but writes directly into the
user buffer. This may require the kernel to swap, right? (Which
means we sleep, right?). So, what we _really_ need is buffered,
non-cached operation. OK... I think I finally get it.

I can be really dense sometimes :)

>> will keep the proc data consistent (no missing or duplicate data),
>> as was the original intent of the caching model.
>> The included patch should apply cleanly to 2.1.7.
>> Comments?
>Bonus points for being able to select() on a /proc file and wake when
>it changes ;)

Well, select() works with the new proc fifos. It is easy to code
a simple proc_notify() that would wake up the select()ed files.

First, take out the S_ISFIFO() check in the proc_g_select() code and
then add the following to proc_fs.h:

extern inline void proc_notify(struct proc_dir_entry *pde)

Now in the kernel (using /proc/net/route as an example), remove
'static' in the definition of proc_net_route and declare it in
net/route.h. Then call proc_notify(&proc_route_net) after every
routing table change... viola - any code waiting in select() for
that file wakes up.

Actually, what we need is a P_CANSELECT flag. That way select will
only work on proc files that support it.


 \ /
  Last update: 2005-03-22 13:38    [W:0.072 / U:0.028 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site