Applications :: Accessing Shared Data Between Threads Using Mutex?

I have written an application which has more than 6 threads.Two threads share a common linked list. Out of two threads one thread reads the linked list node and other thread writes to linked list node.I am using pthread_mutex_lock() API to achieve synchronisation between having access to common linked list. The problem is the first thread which reads the linked list accesses the mutex faster making other thread to starve.

I want both the thread to have an access to mutex. It should not happen that always first thread locks, releases and relocks it. The first thread almost require to access the link list every 5 msec which is causing second thread not to gain the mutex.How should I fix this? For information, I am running this application on PXA270 ARM platform.