Status of multithreaded code

[Ben Hartshorne]

Too quick to hit send.  

I can answer this question - though memcached.h alternately defines
item_get_nocheck as mt_item_get_nocheck or do_item_get_nocheck,
depending on whether it's running with threads, the memcached.c only
uses do_item_get_nocheck instead of the configurable item_get_nocheck.  

The answer is that the multithreaded version has not yet been pulled
into the active code, though it's almost there.

-ben

On Fri, May 25, 2007 at 06:01:45PM -0700, Ben Hartshorne wrote:
> All,
> 
> I saw a --enable-threads option in the configure script, along with a
> thredas.c that contained multithreaded code.
> 
> What is the status of this code?  
> 
> I was looking at the code for mt_item_get_nocheck to get an item
> regardless of its deleted status.
> 
>     392 /*
>     393  * Returns an item whether or not it's been marked as expired or deleted.
>     394  */
>     395 item *mt_item_get_nocheck(char *key, size_t nkey) {
>     396     item *it;
>     397
>     398     pthread_mutex_lock(&cache_lock);
>     399     it = assoc_find(key, nkey);
>     400     it->refcount++;
>     401     pthread_mutex_unlock(&cache_lock);
>     402     return it;
>     403 }
> 
> If assoc_find returns 0 (which it does if the item is a cache miss), it
> looks to me as though the function will segfault when it tries to
> derefernce it in line 400.
> 
> Thoughts?
> 
> The corresponding single-threaded function checks to make sure it is
> valid before derefencing it:
> 
>     402 /* returns an item whether or not it's delete-locked or expired. */
>     403 item *do_item_get_nocheck(const char *key, const size_t nkey) {
>     404     item *it = assoc_find(key, nkey);
>     405     if (it) {
>     406         it->refcount++;
>     407         DEBUG_REFCNT(it, '+');
>     408     }
>     409     return it;
>     410 }
> 
> -ben
> 
> -- 
> Ben Hartshorne
> email: ben at hartshorne.net
> http://ben.hartshorne.net



-- 
Ben Hartshorne
email: ben at hartshorne.net
http://ben.hartshorne.net
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