Re: OOPS with slab cache

[Keith Owens]

On Mon, 10 Jan 2000 16:28:23 -0700 (MST), 
Andreas Dilger <[e-mail]> wrote:
>Hello all,
>Having looked into this slab cache/module problem some more (I read the
>comments that a slab cache should NOT be destroyed at all), it still
>leaves the problem of how to get at the existing cache after a module is
>unloaded and reloaded, if it doesn't keep any memory pointer in-kernel.
>Having "static cache_p" in the module is no good if the module itself
>is unloaded, and patching the kernel for this filesystem module just to
>hold a static pointer is not desirable.

Would a patch to add persistent variables for modules be accepted into
the kernel?  Modules define variables like this

static __persistent cache * cache_p;

__persistent in a module stores the data in a separate ELF section,
when the code is builtin __persistent is a no-op.  modutils and
kernel/modules allocate and initialize storage for __persistent the
first time the module is loaded.  Unloading a module does not remove
the __persistent data, reloading the module will reuse but not
initialize the assigned storage.

Easy enough to code but it is not worth doing unless the patch stands a
chance of being accepted into the kernel.  So would this feature be
worthwhile?