27 typedef struct Palloc	Palloc;  typedef
539 struct Palloc  struct
542 	Pallocmem	mem[4];  argument
543 	Page	*head;			/* most recently used */
544 	Page	*tail;			/* least recently used */
545 	ulong	freecount;		/* how many pages on free list now */
546 	Page	*pages;			/* array of all pages */
547 	ulong	user;			/* how many user pages */
548 	Page	*hash[PGHSIZE];
549 	Lock	hashlock;
550 	Rendez	r;			/* Sleep for free mem */
551 	QLock	pwait;			/* Queue of procs waiting for memory */