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Don't alloc in cursor_push/pop

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vmware
Howard Chu 13 years ago
parent 1ceae5c2c0
commit e15d4d16b6
1 changed files with 29 additions and 51 deletions
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  1. 80
      libraries/libmdb/mdb.c

80
libraries/libmdb/mdb.c
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@ -29,7 +29,6 @@
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/queue.h>
#include <sys/param.h>
#include <sys/uio.h>
#include <sys/mman.h>
@ -231,25 +230,19 @@ static MDB_dpage *mdb_alloc_page(MDB_txn *txn, MDB_page *parent, unsigned int pa
static int mdb_touch(MDB_txn *txn, MDB_pageparent *mp);
typedef struct MDB_ppage { /* ordered list of pages */
SLIST_ENTRY(MDB_ppage) mp_entry;
MDB_page *mp_page;
unsigned int mp_ki; /* cursor index on page */
} MDB_ppage;
SLIST_HEAD(page_stack, MDB_ppage);
/* FIXME: tree depth is mostly bounded, we should just
* use a fixed array and avoid malloc/pointer chasing
*/
#define CURSOR_EMPTY(c) SLIST_EMPTY(&(c)->mc_stack)
#define CURSOR_TOP(c) SLIST_FIRST(&(c)->mc_stack)
#define CURSOR_POP(c) SLIST_REMOVE_HEAD(&(c)->mc_stack, mp_entry)
#define CURSOR_PUSH(c,p) SLIST_INSERT_HEAD(&(c)->mc_stack, p, mp_entry)
#define CURSOR_TOP(c) (&(c)->mc_stack[(c)->mc_snum-1])
#define CURSOR_PARENT(c) (&(c)->mc_stack[(c)->mc_snum-2])
struct MDB_xcursor;
struct MDB_cursor {
MDB_txn *mc_txn;
struct page_stack mc_stack; /* stack of parent pages */
MDB_ppage mc_stack[32]; /* stack of parent pages */
unsigned int mc_snum; /* number of pushed pages */
MDB_dbi mc_dbi;
short mc_initialized; /* 1 if initialized */
short mc_eof; /* 1 if end is reached */
@ -1542,12 +1535,12 @@ cursor_pop_page(MDB_cursor *cursor)
{
MDB_ppage *top;
top = CURSOR_TOP(cursor);
CURSOR_POP(cursor);
DPRINTF("popped page %lu off cursor %p", top->mp_page->mp_pgno, (void *) cursor);
if (cursor->mc_snum) {
top = CURSOR_TOP(cursor);
cursor->mc_snum--;
free(top);
DPRINTF("popped page %lu off cursor %p", top->mp_page->mp_pgno, (void *) cursor);
}
}
static MDB_ppage *
@ -1557,10 +1550,9 @@ cursor_push_page(MDB_cursor *cursor, MDB_page *mp)
DPRINTF("pushing page %lu on cursor %p", mp->mp_pgno, (void *) cursor);
if ((ppage = calloc(1, sizeof(MDB_ppage))) == NULL)
return NULL;
ppage = &cursor->mc_stack[cursor->mc_snum++];
ppage->mp_page = mp;
CURSOR_PUSH(cursor, ppage);
ppage->mp_ki = 0;
return ppage;
}
@ -1794,13 +1786,13 @@ mdb_sibling(MDB_cursor *cursor, int move_right)
{
int rc;
MDB_node *indx;
MDB_ppage *parent, *top;
MDB_ppage *parent;
MDB_page *mp;
top = CURSOR_TOP(cursor);
if ((parent = SLIST_NEXT(top, mp_entry)) == NULL) {
if (cursor->mc_snum < 2) {
return MDB_NOTFOUND; /* root has no siblings */
}
parent = CURSOR_PARENT(cursor);
DPRINTF("parent page is page %lu, index %u",
parent->mp_page->mp_pgno, parent->mp_ki);
@ -1979,8 +1971,7 @@ mdb_cursor_set(MDB_cursor *cursor, MDB_val *key, MDB_val *data,
assert(key);
assert(key->mv_size > 0);
while (CURSOR_TOP(cursor) != NULL)
cursor_pop_page(cursor);
cursor->mc_snum = 0;
rc = mdb_search_page(cursor->mc_txn, cursor->mc_dbi, key, cursor, 0, &mpp);
if (rc != MDB_SUCCESS)
@ -2054,8 +2045,7 @@ mdb_cursor_first(MDB_cursor *cursor, MDB_val *key, MDB_val *data)
MDB_pageparent mpp;
MDB_node *leaf;
while (CURSOR_TOP(cursor) != NULL)
cursor_pop_page(cursor);
cursor->mc_snum = 0;
rc = mdb_search_page(cursor->mc_txn, cursor->mc_dbi, NULL, cursor, 0, &mpp);
if (rc != MDB_SUCCESS)
@ -2089,8 +2079,7 @@ mdb_cursor_last(MDB_cursor *cursor, MDB_val *key, MDB_val *data)
MDB_node *leaf;
MDB_val lkey;
while (CURSOR_TOP(cursor) != NULL)
cursor_pop_page(cursor);
cursor->mc_snum = 0;
lkey.mv_size = MAXKEYSIZE+1;
lkey.mv_data = NULL;
@ -2387,7 +2376,7 @@ mdb_xcursor_init0(MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx)
mx->mx_dbxs[dbn+1].md_dirty = 0;
mx->mx_txn.mt_numdbs = dbn+2;
SLIST_INIT(&mx->mx_cursor.mc_stack);
mx->mx_cursor.mc_snum = 0;
mx->mx_cursor.mc_txn = &mx->mx_txn;
mx->mx_cursor.mc_dbi = dbn+1;
}
@ -2442,7 +2431,6 @@ mdb_cursor_open(MDB_txn *txn, MDB_dbi dbi, MDB_cursor **ret)
size += sizeof(MDB_xcursor);
if ((cursor = calloc(1, size)) != NULL) {
SLIST_INIT(&cursor->mc_stack);
cursor->mc_dbi = dbi;
cursor->mc_txn = txn;
if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT) {
@ -2480,13 +2468,6 @@ void
mdb_cursor_close(MDB_cursor *cursor)
{
if (cursor != NULL) {
while(!CURSOR_EMPTY(cursor))
cursor_pop_page(cursor);
if (cursor->mc_txn->mt_dbs[cursor->mc_dbi].md_flags & MDB_DUPSORT) {
while(!CURSOR_EMPTY(&cursor->mc_xcursor->mx_cursor))
cursor_pop_page(&cursor->mc_xcursor->mx_cursor);
}
free(cursor);
}
}
@ -2852,24 +2833,21 @@ mdb_del(MDB_txn *txn, MDB_dbi dbi,
unsigned int i;
cursor_pop_page(&mx.mx_cursor);
top = CURSOR_TOP(&mx.mx_cursor);
if (top != NULL) {
parent = SLIST_NEXT(top, mp_entry);
while (parent != NULL) {
if (mx.mx_cursor.mc_snum) {
top = CURSOR_TOP(&mx.mx_cursor);
while (mx.mx_cursor.mc_snum > 1) {
parent = CURSOR_PARENT(&mx.mx_cursor);
for (i=0; i<NUMKEYS(top->mp_page); i++) {
ni = NODEPTR(top->mp_page, i);
mdb_midl_insert(txn->mt_free_pgs, ni->mn_pgno);
}
if (parent) {
parent->mp_ki++;
if (parent->mp_ki >= NUMKEYS(parent->mp_page)) {
cursor_pop_page(&mx.mx_cursor);
top = CURSOR_TOP(&mx.mx_cursor);
parent = SLIST_NEXT(top, mp_entry);
} else {
ni = NODEPTR(parent->mp_page, parent->mp_ki);
top->mp_page = mdb_get_page(&mx.mx_txn, ni->mn_pgno);
}
parent->mp_ki++;
if (parent->mp_ki >= NUMKEYS(parent->mp_page)) {
cursor_pop_page(&mx.mx_cursor);
top = parent;
} else {
ni = NODEPTR(parent->mp_page, parent->mp_ki);
top->mp_page = mdb_get_page(&mx.mx_txn, ni->mn_pgno);
}
}
}

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