include/asm-i386/shmparam.h

11734 #ifndef _ASMI386_SHMPARAM_H
11735 #define _ASMI386_SHMPARAM_H
11736 
11737 /* address range for shared memory attaches if no address
11738  * passed to shmat() */
11739 #define SHM_RANGE_START 0x50000000
11740 #define SHM_RANGE_END   0x60000000
11741 
11742 /* Format of a swap-entry for shared memory pages
11743  * currently out in swap space (see also mm/swap.c).
11744  *
11745  * SWP_TYPE = SHM_SWP_TYPE
11746  * SWP_OFFSET is used as follows:
11747  *  bits 0..6 : id of shared memory segment page belongs
11748  *  to (SHM_ID)
11749  *  bits 7..21: index of page within shared memory
11750  *  segment (SHM_IDX) (actually fewer bits get used since
11751  *  SHMMAX is so low) */
11752 
11753 /* Keep _SHM_ID_BITS as low as possible since SHMMNI
11754  * depends on it and there is a static array of size
11755  * SHMMNI.  */
11756 #define _SHM_ID_BITS    7
11757 #define SHM_ID_MASK     ((1<<_SHM_ID_BITS)-1)
11758 
11759 #define SHM_IDX_SHIFT   (_SHM_ID_BITS)
11760 #define _SHM_IDX_BITS   15
11761 #define SHM_IDX_MASK    ((1<<_SHM_IDX_BITS)-1)
11762 
11763 /* _SHM_ID_BITS + _SHM_IDX_BITS must be <= 24 on the i386
11764  * and SHMMAX <= (PAGE_SIZE << _SHM_IDX_BITS).  */
11765 
11766 #define SHMMAX 0x2000000 /* max shared seg size (bytes)*/
11767 /* Try not to change the default shipped SHMMAX - people
11768  * rely on it */
11769 
11770 /* min shared seg size (bytes) */
11771 #define SHMMIN 1        /* really PAGE_SIZE */
11772 /* max num of segs system wide */
11773 #define SHMMNI (1<<_SHM_ID_BITS)
11774 /* max shm system wide (pages) */
11775 #define SHMALL (1<<(_SHM_IDX_BITS+_SHM_ID_BITS))
11776 /* attach addr a multiple of this */
11777 #define SHMLBA PAGE_SIZE
11778 /* max shared segs per process */
11779 #define SHMSEG SHMMNI
11780 
11781 #endif /* _ASMI386_SHMPARAM_H */