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cache.h
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/* CACHE.H (c)Copyright Greg Smith, 2002-2012 */
/* Buffer Cache Manager */
/* */
/* Released under "The Q Public License Version 1" */
/* (http://www.hercules-390.org/herclic.html) as modifications to */
/* Hercules. */
/*-------------------------------------------------------------------
Description:
Manages multiple caches in a multi-threaded environment. A cache
is dynamically created and destroyed. It's size or number of
entries is also dynamically determined. A cache entry contains
an identifying `key', `flags' which indicate whether an entry is
busy or not, and a `buf' which is a pointer to the cached object.
Cache entry:
The structure of a cache entry is:
U64 key;
U32 flag;
int len;
void *buf;
int value;
U64 age;
The first 8 bits of the flag indicates if the entry is `busy' or
not. If any of the first 8 bits are non-zero then the entry is
considered `busy' and will not be stolen or otherwise reused.
APIs:
General query functions:
int cache_nbr(int ix); [0]
Number of entries
int cache_busy(int ix);
Number of busy entries
int cache_empty(int ix);
Number of empty entries [1]
int cache_waiters(int ix);
Number of waiters for a non-busy cache entry
S64 cache_size(int ix);
Size of all allocated objects
S64 cache_hits(int ix);
Number of successful lookups
S64 cache_misses(int ix);
Number of unsuccessful lookups
int cache_busy_percent(int ix);
Percentage (0 .. 100) of entries that are busy
int cache_empty_percent(int ix);
Percentage of entries that are empty [1]
int cache_hit_percent(int ix);
Percentage of successful lookups to total lookups
Notes [0] `ix' identifies the cache. This is an integer
and is reserved in `cache.h'
[1] An empty entry contains a zero key value.
A valid key should not be all zeroes
(0x0000000000000000) or all ones
(0xffffffffffffffff). All ones is used to
indicate an error circumstance.
Entry specific functions:
U64 cache_getkey(int ix, int i); [0]
Return key for the specified cache entry
U64 cache_setkey(int ix, int i, U64 key);
Set the key for the specified cache entry;
the old key is returned
U32 cache_getflag(int ix, int i);
Return the flag for the specified cache entry
U32 cache_setflag(int ix, int i, U32 andbits, U32 orbits);
Set the flag for the specified cache entry; first
the `andbits' value is `and'ed against the entry then
the `orbits' value is `or'ed against the entry. The
old flag is returned.
U64 cache_getage(int ix, int i); [1]
Return age for the specified cache entry
U64 cache_setage(int ix, int i);
Set age for the specified cache entry
void *cache_getbuf(int ix, int i, int len);
Return address of the object buf for the cache entry.
If `len' is non-zero, then if the current object
is null or `len' is greater than the current object
length then the old object is freed and a new
object is obtained.
void *cache_setbuf(int ix, int i, void *buf, int len);
The old object address and length is replaced.
The address of the old object is returned and
can be freed using `free()'.
int cache_getlen(int ix, int i);
Return the length of the current object
Notes [0] `i' is the index of the entry in cache `ix'
[1] `age' is a sequentially incremented value and
does not correspond to date or time
Locking functions:
int cache_lock(int ix);
Obtain the lock for cache `ix'. If the cache does
not exist then it will be created. Generally, the
lock should be obtained when referencing cache
entries and must be held when a cache entry status
may change from `busy' to `not busy' or vice versa.
Likewise, the lock must be held when a cache entry
changes from `empty' to `not empty' or vice versa.
int cache_unlock(int ix);
Release the cache lock
Search functions:
int cache_lookup(int ix, U64 key, int *o);
Search cache `ix' for entry matching `key'.
If a non-NULL pointer `o' is provided, then the
oldest or preferred cache entry index is returned
that is available to be stolen.
int cache_scan (int ix, int (rtn)(), void *data);
Scan a cache routine entry by entry calling routine
`rtn'. Parameters passed to the routine are
`(int *answer, int ix, int i, void *data)' where
`ix' is the cache index, `i' is the cache entry
index and `data' is the value passed to cache_scan.
`*answer' is initialized to -1 and can be set by
the scan subroutine. This will be the value returned
by cache_scan. If the routine returns a non-zero
value then the scan is terminated.
Other functions:
int cache_wait(int ix);
Wait for a non-busy cache entry to become available.
Typically called after `cache_lookup' was
unsuccessful and `*o' is -1.
int cache_release(int ix, int i, int flag);
Release the cache entry. If flag is CACHE_FREEBUF
then the object buffer is also freed.
-------------------------------------------------------------------*/
#ifndef _HERCULES_CACHE_H
#define _HERCULES_CACHE_H 1
#include "hercules.h"
/*-------------------------------------------------------------------*/
/* Reserve cache indexes here */
/*-------------------------------------------------------------------*/
#define CACHE_MAX_INDEX 8 /* Max number caches [0..7] */
#define CACHE_DEVBUF 0 /* Device Buffer cache */
#define CACHE_L2 1 /* L2 cache */
#define CACHE_2 2 /* (available) */
#define CACHE_3 3 /* (available) */
#define CACHE_4 4 /* (available) */
#define CACHE_5 5 /* (available) */
#define CACHE_6 6 /* (available) */
#define CACHE_7 7 /* (available) */
#ifdef _CACHE_C_
/*-------------------------------------------------------------------*/
/* Cache entry */
/*-------------------------------------------------------------------*/
typedef struct _CACHE { /* Cache entry */
U64 key; /* Key */
U32 flag; /* Flags */
int len; /* Buffer length */
void *buf; /* Buffer address */
int value; /* Arbitrary value */
U64 age; /* Age */
} CACHE;
/*-------------------------------------------------------------------*/
/* Cache header */
/*-------------------------------------------------------------------*/
typedef struct _CACHEBLK { /* Cache header */
int magic; /* Magic number */
int nbr; /* Number entries */
int busy; /* Number busy entries */
int empty; /* Number empty entries */
int waiters; /* Number waiters */
int waits; /* Number times waited */
S64 size; /* Allocated buffer size */
S64 hits; /* Number lookup hits */
S64 fasthits; /* Number fast lookup hits */
S64 misses; /* Number lookup misses */
U64 age; /* Age counter */
LOCK lock; /* Lock */
COND waitcond; /* Wait for available entry */
CACHE *cache; /* Cache table address */
time_t atime; /* Time last adjustment */
time_t wtime; /* Time last wait */
int adjusts; /* Number of adjustments */
} CACHEBLK;
#endif
/*-------------------------------------------------------------------*/
/* Flag definitions */
/*-------------------------------------------------------------------*/
#define CACHE_BUSY 0xFF000000 /* Busy bits */
#define CACHE_TYPE 0x000000FF /* Type bits */
#define CACHE_FREEBUF 1 /* Free buf on release */
#ifdef _CACHE_C_
#define CACHE_MAGIC 0x01CACE10 /* Magic number */
#define CACHE_DEFAULT_NBR 229 /* Initial entries (prime) */
//FIXME the line below increases the size for CACHE_L2. Since each
// cckd device always has an active l2 entry this number
// actually limits the number of cckd devices that can be
// attached.
// This is a workaround to increase the max number of devices
#define CACHE_DEFAULT_L2_NBR 1031 /* Initial entries for L2 */
#define CACHE_WAITTIME 1000 /* Wait time for entry(usec) */
#define CACHE_ADJUST_INTERVAL 15 /* Adjustment interval (sec) */
#define CACHE_ADJUST_NUMBER 128 /* Uninhibited nbr entries */
#define CACHE_ADJUST_BUSY1 70 /* Increase when this busy 1 */
#define CACHE_ADJUST_BUSY2 80 /* Increase when this busy 2 */
#define CACHE_ADJUST_RESIZE 8 /* Nbr entries adjusted */
#define CACHE_ADJUST_EMPTY 16 /* Decrease this many empty */
#define CACHE_ADJUST_HIT1 60 /* Increase hit% this low 1 */
#define CACHE_ADJUST_HIT2 50 /* Increase hit% this low 2 */
#define CACHE_ADJUST_BUSY3 20 /* Decrease not this busy */
#define CACHE_ADJUST_HIT3 90 /* and hit% this high */
#define CACHE_ADJUST_SIZE (8*1024*1024)/* and size this high */
#define CACHE_ADJUST_WAITTIME 10 /* Increase last wait (sec) */
#endif
/*-------------------------------------------------------------------*/
/* Functions */
/*-------------------------------------------------------------------*/
CCH_DLL_IMPORT int cachestats_cmd(int argc, char *argv[], char *cmdline);
int cache_nbr(int ix);
int cache_busy(int ix);
int cache_empty(int ix);
int cache_waiters(int ix);
S64 cache_size(int ix);
S64 cache_hits(int ix);
S64 cache_misses(int ix);
int cache_busy_percent(int ix);
int cache_empty_percent(int ix);
int cache_hit_percent(int ix);
int cache_lookup(int ix, U64 key, int *o);
typedef int CACHE_SCAN_RTN (int *answer, int ix, int i, void *data);
int cache_scan (int ix, CACHE_SCAN_RTN rtn, void *data);
int cache_lock(int ix);
int cache_unlock(int ix);
int cache_wait(int ix);
U64 cache_getkey(int ix, int i);
U64 cache_setkey(int ix, int i, U64 key);
U32 cache_getflag(int ix, int i);
U32 cache_setflag(int ix, int i, U32 andbits, U32 orbits);
U64 cache_getage(int ix, int i);
U64 cache_setage(int ix, int i);
void *cache_getbuf(int ix, int i, int len);
void *cache_setbuf(int ix, int i, void *buf, int len);
int cache_getlen(int ix, int i);
int cache_getval(int ix, int i);
int cache_setval(int ix, int i, int val);
int cache_release(int ix, int i, int flag);
#ifdef _CACHE_C_
static int cache_create (int ix);
static int cache_destroy (int ix);
static int cache_check_ix(int ix);
static int cache_check_cache(int ix);
static int cache_check(int ix, int i);
static int cache_isbusy(int ix, int i);
static int cache_isempty(int ix, int i);
static int cache_adjust(int ix, int n);
#if 0
static int cache_resize (int ix, int n);
#endif
static void cache_allocbuf(int ix, int i, int len);
#endif
/*-------------------------------------------------------------------*/
/* Specific cache definitions (until a better place is found) */
/*-------------------------------------------------------------------*/
/*-------------------------------------------------------------------*/
/* Device buffer definitions */
/*-------------------------------------------------------------------*/
#define CCKD_CACHE_ACTIVE 0x80000000 /* Active entry */
#define CCKD_CACHE_READING 0x40000000 /* Entry being read */
#define CCKD_CACHE_WRITING 0x20000000 /* Entry being written */
#define CCKD_CACHE_IOBUSY (CCKD_CACHE_READING|CCKD_CACHE_WRITING)
#define CCKD_CACHE_IOWAIT 0x10000000 /* Waiters for i/o */
#define CCKD_CACHE_UPDATED 0x08000000 /* Buffer has been updated */
#define CCKD_CACHE_WRITE 0x04000000 /* Entry pending write */
#define CCKD_CACHE_USED 0x00800000 /* Entry has been used */
#define CKD_CACHE_ACTIVE 0x80000000 /* Active entry */
#define FBA_CACHE_ACTIVE 0x80000000 /* Active entry */
#define SHRD_CACHE_ACTIVE 0x80000000 /* Active entry */
#define DEVBUF_TYPE_SHARED 0x00000080 /* Shared entry type */
#define DEVBUF_TYPE_COMP 0x00000040 /* CCKD/CFBA entry type */
#define DEVBUF_TYPE_CKD 0x00000002 /* CKD entry type */
#define DEVBUF_TYPE_FBA 0x00000001 /* FBA entry type */
#define DEVBUF_TYPE_CCKD (DEVBUF_TYPE_COMP|DEVBUF_TYPE_CKD)
#define DEVBUF_TYPE_CFBA (DEVBUF_TYPE_COMP|DEVBUF_TYPE_FBA)
#define DEVBUF_TYPE_SCKD (DEVBUF_TYPE_SHARED|DEVBUF_TYPE_CKD)
#define DEVBUF_TYPE_SFBA (DEVBUF_TYPE_SHARED|DEVBUF_TYPE_FBA)
#define CCKD_CACHE_GETKEY(_ix, _devnum, _trk) \
do { \
(_devnum) = (U16)((cache_getkey(CACHE_DEVBUF,(_ix)) >> 32) & 0xFFFF); \
(_trk) = (U32)(cache_getkey(CACHE_DEVBUF,(_ix)) & 0xFFFFFFFF); \
} while (0)
#define CCKD_CACHE_SETKEY(_devnum, _trk) \
((U64)(((U64)(_devnum) << 32) | (U64)(_trk)))
#define CKD_CACHE_GETKEY(_ix, _devnum, _trk) \
{ \
(_devnum) = (U16)((cache_getkey(CACHE_DEVBUF,(_ix)) >> 32) & 0xFFFF); \
(_trk) = (U32)(cache_getkey(CACHE_DEVBUF,(_ix)) & 0xFFFFFFFF); \
}
#define CKD_CACHE_SETKEY(_devnum, _trk) \
((U64)(((U64)(_devnum) << 32) | (U64)(_trk)))
#define FBA_CACHE_GETKEY(_ix, _devnum, _blkgrp) \
{ \
(_devnum) = (U16)((cache_getkey(CACHE_DEVBUF,(_ix)) >> 32) & 0xFFFF); \
(_blkgrp) = (U32)(cache_getkey(CACHE_DEVBUF,(_ix)) & 0xFFFFFFFF); \
}
#define FBA_CACHE_SETKEY(_devnum, _blkgrp) \
((U64)(((U64)(_devnum) << 32) | (U64)(_blkgrp)))
#define SHRD_CACHE_GETKEY(_ix, _devnum, _trk) \
{ \
(_devnum) = (U16)((cache_getkey(CACHE_DEVBUF,(_ix)) >> 32) & 0xFFFF); \
(_trk) = (U32)(cache_getkey(CACHE_DEVBUF,(_ix)) & 0xFFFFFFFF); \
}
#define SHRD_CACHE_SETKEY(_devnum, _trk) \
((U64)(((U64)(_devnum) << 32) | (U64)(_trk)))
/*-------------------------------------------------------------------*/
/* L2 definitions */
/*-------------------------------------------------------------------*/
#define L2_CACHE_ACTIVE 0x80000000 /* Active entry */
#define L2_CACHE_GETKEY(_ix, _sfx, _devnum, _trk) \
do { \
(_sfx) = (U16)((cache_getkey(CACHE_L2,(_ix)) >> 48) & 0xFFFF); \
(_devnum) = (U16)((cache_getkey(CACHE_L2,(_ix)) >> 32) & 0xFFFF); \
(_trk) = (U32)(cache_getkey(CACHE_L2,(_ix)) & 0xFFFFFFFF); \
} while (0)
#define L2_CACHE_SETKEY(_sfx, _devnum, _trk) \
((U64)(((U64)(_sfx) << 48) | ((U64)(_devnum) << 32) | (U64)(_trk)))
#endif /* _HERCULES_CACHE_H */