5e3be1be09
Technically declaring a prototype with an empty declaration has been deprecated since the early days of C, but we never got a warning for it. C2x will apparently be introducing a breaking change if you are using this type of declarator, so Clang 15 has started issuing a warning with -pedantic. Although not apparently a problem for any of the compiler we build on, if feels like the right thing is to properly adhere to the C standard and use (void).
1080 lines
39 KiB
C
1080 lines
39 KiB
C
/*
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* Active memory defragmentation
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* Try to find key / value allocations that need to be re-allocated in order
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* to reduce external fragmentation.
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* We do that by scanning the keyspace and for each pointer we have, we can try to
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* ask the allocator if moving it to a new address will help reduce fragmentation.
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*
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* Copyright (c) 2020, Redis Labs, Inc
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* * Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of Redis nor the names of its contributors may be used
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* to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "server.h"
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#include "cluster.h"
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#include <time.h>
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#include <assert.h>
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#include <stddef.h>
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#ifdef HAVE_DEFRAG
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/* this method was added to jemalloc in order to help us understand which
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* pointers are worthwhile moving and which aren't */
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int je_get_defrag_hint(void* ptr);
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/* Defrag helper for generic allocations.
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*
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* returns NULL in case the allocation wasn't moved.
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* when it returns a non-null value, the old pointer was already released
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* and should NOT be accessed. */
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void* activeDefragAlloc(void *ptr) {
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size_t size;
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void *newptr;
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if(!je_get_defrag_hint(ptr)) {
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server.stat_active_defrag_misses++;
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return NULL;
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}
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/* move this allocation to a new allocation.
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* make sure not to use the thread cache. so that we don't get back the same
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* pointers we try to free */
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size = zmalloc_size(ptr);
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newptr = zmalloc_no_tcache(size);
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memcpy(newptr, ptr, size);
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zfree_no_tcache(ptr);
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server.stat_active_defrag_hits++;
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return newptr;
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}
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/*Defrag helper for sds strings
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*
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* returns NULL in case the allocation wasn't moved.
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* when it returns a non-null value, the old pointer was already released
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* and should NOT be accessed. */
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sds activeDefragSds(sds sdsptr) {
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void* ptr = sdsAllocPtr(sdsptr);
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void* newptr = activeDefragAlloc(ptr);
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if (newptr) {
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size_t offset = sdsptr - (char*)ptr;
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sdsptr = (char*)newptr + offset;
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return sdsptr;
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}
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return NULL;
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}
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/* Defrag helper for robj and/or string objects
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*
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* returns NULL in case the allocation wasn't moved.
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* when it returns a non-null value, the old pointer was already released
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* and should NOT be accessed. */
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robj *activeDefragStringOb(robj* ob) {
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robj *ret = NULL;
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if (ob->refcount!=1)
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return NULL;
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/* try to defrag robj (only if not an EMBSTR type (handled below). */
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if (ob->type!=OBJ_STRING || ob->encoding!=OBJ_ENCODING_EMBSTR) {
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if ((ret = activeDefragAlloc(ob))) {
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ob = ret;
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}
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}
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/* try to defrag string object */
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if (ob->type == OBJ_STRING) {
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if(ob->encoding==OBJ_ENCODING_RAW) {
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sds newsds = activeDefragSds((sds)ob->ptr);
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if (newsds) {
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ob->ptr = newsds;
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}
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} else if (ob->encoding==OBJ_ENCODING_EMBSTR) {
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/* The sds is embedded in the object allocation, calculate the
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* offset and update the pointer in the new allocation. */
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long ofs = (intptr_t)ob->ptr - (intptr_t)ob;
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if ((ret = activeDefragAlloc(ob))) {
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ret->ptr = (void*)((intptr_t)ret + ofs);
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}
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} else if (ob->encoding!=OBJ_ENCODING_INT) {
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serverPanic("Unknown string encoding");
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}
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}
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return ret;
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}
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/* Defrag helper for lua scripts
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*
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* returns NULL in case the allocation wasn't moved.
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* when it returns a non-null value, the old pointer was already released
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* and should NOT be accessed. */
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luaScript *activeDefragLuaScript(luaScript *script) {
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luaScript *ret = NULL;
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/* try to defrag script struct */
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if ((ret = activeDefragAlloc(script))) {
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script = ret;
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}
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/* try to defrag actual script object */
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robj *ob = activeDefragStringOb(script->body);
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if (ob) script->body = ob;
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return ret;
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}
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/* Defrag helper for dict main allocations (dict struct, and hash tables).
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* receives a pointer to the dict* and implicitly updates it when the dict
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* struct itself was moved. Returns a stat of how many pointers were moved. */
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void dictDefragTables(dict* d) {
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dictEntry **newtable;
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/* handle the first hash table */
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newtable = activeDefragAlloc(d->ht_table[0]);
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if (newtable)
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d->ht_table[0] = newtable;
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/* handle the second hash table */
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if (d->ht_table[1]) {
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newtable = activeDefragAlloc(d->ht_table[1]);
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if (newtable)
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d->ht_table[1] = newtable;
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}
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}
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/* Internal function used by zslDefrag */
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void zslUpdateNode(zskiplist *zsl, zskiplistNode *oldnode, zskiplistNode *newnode, zskiplistNode **update) {
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int i;
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for (i = 0; i < zsl->level; i++) {
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if (update[i]->level[i].forward == oldnode)
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update[i]->level[i].forward = newnode;
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}
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serverAssert(zsl->header!=oldnode);
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if (newnode->level[0].forward) {
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serverAssert(newnode->level[0].forward->backward==oldnode);
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newnode->level[0].forward->backward = newnode;
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} else {
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serverAssert(zsl->tail==oldnode);
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zsl->tail = newnode;
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}
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}
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/* Defrag helper for sorted set.
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* Update the robj pointer, defrag the skiplist struct and return the new score
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* reference. We may not access oldele pointer (not even the pointer stored in
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* the skiplist), as it was already freed. Newele may be null, in which case we
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* only need to defrag the skiplist, but not update the obj pointer.
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* When return value is non-NULL, it is the score reference that must be updated
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* in the dict record. */
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double *zslDefrag(zskiplist *zsl, double score, sds oldele, sds newele) {
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zskiplistNode *update[ZSKIPLIST_MAXLEVEL], *x, *newx;
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int i;
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sds ele = newele? newele: oldele;
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/* find the skiplist node referring to the object that was moved,
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* and all pointers that need to be updated if we'll end up moving the skiplist node. */
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x = zsl->header;
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for (i = zsl->level-1; i >= 0; i--) {
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while (x->level[i].forward &&
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x->level[i].forward->ele != oldele && /* make sure not to access the
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->obj pointer if it matches
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oldele */
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(x->level[i].forward->score < score ||
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(x->level[i].forward->score == score &&
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sdscmp(x->level[i].forward->ele,ele) < 0)))
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x = x->level[i].forward;
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update[i] = x;
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}
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/* update the robj pointer inside the skip list record. */
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x = x->level[0].forward;
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serverAssert(x && score == x->score && x->ele==oldele);
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if (newele)
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x->ele = newele;
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/* try to defrag the skiplist record itself */
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newx = activeDefragAlloc(x);
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if (newx) {
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zslUpdateNode(zsl, x, newx, update);
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return &newx->score;
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}
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return NULL;
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}
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/* Defrag helper for sorted set.
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* Defrag a single dict entry key name, and corresponding skiplist struct */
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void activeDefragZsetEntry(zset *zs, dictEntry *de) {
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sds newsds;
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double* newscore;
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sds sdsele = dictGetKey(de);
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if ((newsds = activeDefragSds(sdsele)))
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dictSetKey(zs->dict, de, newsds);
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newscore = zslDefrag(zs->zsl, *(double*)dictGetVal(de), sdsele, newsds);
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if (newscore) {
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dictSetVal(zs->dict, de, newscore);
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}
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}
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#define DEFRAG_SDS_DICT_NO_VAL 0
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#define DEFRAG_SDS_DICT_VAL_IS_SDS 1
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#define DEFRAG_SDS_DICT_VAL_IS_STROB 2
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#define DEFRAG_SDS_DICT_VAL_VOID_PTR 3
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#define DEFRAG_SDS_DICT_VAL_LUA_SCRIPT 4
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void activeDefragSdsDictCallback(void *privdata, const dictEntry *de) {
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UNUSED(privdata);
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UNUSED(de);
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}
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/* Defrag a dict with sds key and optional value (either ptr, sds or robj string) */
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void activeDefragSdsDict(dict* d, int val_type) {
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unsigned long cursor = 0;
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dictDefragFunctions defragfns = {
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.defragAlloc = activeDefragAlloc,
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.defragKey = (dictDefragAllocFunction *)activeDefragSds,
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.defragVal = (val_type == DEFRAG_SDS_DICT_VAL_IS_SDS ? (dictDefragAllocFunction *)activeDefragSds :
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val_type == DEFRAG_SDS_DICT_VAL_IS_STROB ? (dictDefragAllocFunction *)activeDefragStringOb :
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val_type == DEFRAG_SDS_DICT_VAL_VOID_PTR ? (dictDefragAllocFunction *)activeDefragAlloc :
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val_type == DEFRAG_SDS_DICT_VAL_LUA_SCRIPT ? (dictDefragAllocFunction *)activeDefragLuaScript :
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NULL)
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};
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do {
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cursor = dictScanDefrag(d, cursor, activeDefragSdsDictCallback,
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&defragfns, NULL);
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} while (cursor != 0);
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}
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/* Defrag a list of ptr, sds or robj string values */
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void activeDefragList(list *l, int val_type) {
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listNode *ln, *newln;
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for (ln = l->head; ln; ln = ln->next) {
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if ((newln = activeDefragAlloc(ln))) {
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if (newln->prev)
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newln->prev->next = newln;
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else
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l->head = newln;
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if (newln->next)
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newln->next->prev = newln;
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else
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l->tail = newln;
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ln = newln;
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}
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if (val_type == DEFRAG_SDS_DICT_VAL_IS_SDS) {
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sds newsds, sdsele = ln->value;
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if ((newsds = activeDefragSds(sdsele)))
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ln->value = newsds;
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} else if (val_type == DEFRAG_SDS_DICT_VAL_IS_STROB) {
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robj *newele, *ele = ln->value;
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if ((newele = activeDefragStringOb(ele)))
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ln->value = newele;
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} else if (val_type == DEFRAG_SDS_DICT_VAL_VOID_PTR) {
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void *newptr, *ptr = ln->value;
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if ((newptr = activeDefragAlloc(ptr)))
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ln->value = newptr;
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}
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}
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}
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void activeDefragQuickListNode(quicklist *ql, quicklistNode **node_ref) {
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quicklistNode *newnode, *node = *node_ref;
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unsigned char *newzl;
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if ((newnode = activeDefragAlloc(node))) {
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if (newnode->prev)
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newnode->prev->next = newnode;
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else
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ql->head = newnode;
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if (newnode->next)
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newnode->next->prev = newnode;
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else
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ql->tail = newnode;
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*node_ref = node = newnode;
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}
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if ((newzl = activeDefragAlloc(node->entry)))
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node->entry = newzl;
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}
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void activeDefragQuickListNodes(quicklist *ql) {
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quicklistNode *node = ql->head;
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while (node) {
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activeDefragQuickListNode(ql, &node);
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node = node->next;
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}
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}
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/* when the value has lots of elements, we want to handle it later and not as
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* part of the main dictionary scan. this is needed in order to prevent latency
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* spikes when handling large items */
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void defragLater(redisDb *db, dictEntry *kde) {
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sds key = sdsdup(dictGetKey(kde));
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listAddNodeTail(db->defrag_later, key);
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}
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/* returns 0 if no more work needs to be been done, and 1 if time is up and more work is needed. */
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long scanLaterList(robj *ob, unsigned long *cursor, long long endtime) {
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quicklist *ql = ob->ptr;
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quicklistNode *node;
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long iterations = 0;
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int bookmark_failed = 0;
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if (ob->type != OBJ_LIST || ob->encoding != OBJ_ENCODING_QUICKLIST)
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return 0;
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if (*cursor == 0) {
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/* if cursor is 0, we start new iteration */
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node = ql->head;
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} else {
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node = quicklistBookmarkFind(ql, "_AD");
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if (!node) {
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/* if the bookmark was deleted, it means we reached the end. */
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*cursor = 0;
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return 0;
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}
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node = node->next;
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}
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(*cursor)++;
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while (node) {
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activeDefragQuickListNode(ql, &node);
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server.stat_active_defrag_scanned++;
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if (++iterations > 128 && !bookmark_failed) {
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if (ustime() > endtime) {
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if (!quicklistBookmarkCreate(&ql, "_AD", node)) {
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bookmark_failed = 1;
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} else {
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ob->ptr = ql; /* bookmark creation may have re-allocated the quicklist */
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return 1;
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}
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}
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iterations = 0;
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}
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node = node->next;
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}
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quicklistBookmarkDelete(ql, "_AD");
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*cursor = 0;
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return bookmark_failed? 1: 0;
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}
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typedef struct {
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zset *zs;
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} scanLaterZsetData;
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void scanLaterZsetCallback(void *privdata, const dictEntry *_de) {
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dictEntry *de = (dictEntry*)_de;
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scanLaterZsetData *data = privdata;
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activeDefragZsetEntry(data->zs, de);
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server.stat_active_defrag_scanned++;
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}
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void scanLaterZset(robj *ob, unsigned long *cursor) {
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if (ob->type != OBJ_ZSET || ob->encoding != OBJ_ENCODING_SKIPLIST)
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return;
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zset *zs = (zset*)ob->ptr;
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dict *d = zs->dict;
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scanLaterZsetData data = {zs};
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dictDefragFunctions defragfns = {.defragAlloc = activeDefragAlloc};
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*cursor = dictScanDefrag(d, *cursor, scanLaterZsetCallback, &defragfns, &data);
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}
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/* Used as scan callback when all the work is done in the dictDefragFunctions. */
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void scanCallbackCountScanned(void *privdata, const dictEntry *de) {
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UNUSED(privdata);
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UNUSED(de);
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server.stat_active_defrag_scanned++;
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}
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void scanLaterSet(robj *ob, unsigned long *cursor) {
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if (ob->type != OBJ_SET || ob->encoding != OBJ_ENCODING_HT)
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return;
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dict *d = ob->ptr;
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dictDefragFunctions defragfns = {
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.defragAlloc = activeDefragAlloc,
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.defragKey = (dictDefragAllocFunction *)activeDefragSds
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};
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*cursor = dictScanDefrag(d, *cursor, scanCallbackCountScanned, &defragfns, NULL);
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}
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void scanLaterHash(robj *ob, unsigned long *cursor) {
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if (ob->type != OBJ_HASH || ob->encoding != OBJ_ENCODING_HT)
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return;
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dict *d = ob->ptr;
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dictDefragFunctions defragfns = {
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.defragAlloc = activeDefragAlloc,
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.defragKey = (dictDefragAllocFunction *)activeDefragSds,
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.defragVal = (dictDefragAllocFunction *)activeDefragSds
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};
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*cursor = dictScanDefrag(d, *cursor, scanCallbackCountScanned, &defragfns, NULL);
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}
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void defragQuicklist(redisDb *db, dictEntry *kde) {
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robj *ob = dictGetVal(kde);
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quicklist *ql = ob->ptr, *newql;
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serverAssert(ob->type == OBJ_LIST && ob->encoding == OBJ_ENCODING_QUICKLIST);
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if ((newql = activeDefragAlloc(ql)))
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ob->ptr = ql = newql;
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if (ql->len > server.active_defrag_max_scan_fields)
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defragLater(db, kde);
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else
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activeDefragQuickListNodes(ql);
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}
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void defragZsetSkiplist(redisDb *db, dictEntry *kde) {
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robj *ob = dictGetVal(kde);
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zset *zs = (zset*)ob->ptr;
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zset *newzs;
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zskiplist *newzsl;
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dict *newdict;
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dictEntry *de;
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struct zskiplistNode *newheader;
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serverAssert(ob->type == OBJ_ZSET && ob->encoding == OBJ_ENCODING_SKIPLIST);
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if ((newzs = activeDefragAlloc(zs)))
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ob->ptr = zs = newzs;
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if ((newzsl = activeDefragAlloc(zs->zsl)))
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zs->zsl = newzsl;
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if ((newheader = activeDefragAlloc(zs->zsl->header)))
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zs->zsl->header = newheader;
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if (dictSize(zs->dict) > server.active_defrag_max_scan_fields)
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defragLater(db, kde);
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else {
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dictIterator *di = dictGetIterator(zs->dict);
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while((de = dictNext(di)) != NULL) {
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activeDefragZsetEntry(zs, de);
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}
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dictReleaseIterator(di);
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}
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/* handle the dict struct */
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if ((newdict = activeDefragAlloc(zs->dict)))
|
|
zs->dict = newdict;
|
|
/* defrag the dict tables */
|
|
dictDefragTables(zs->dict);
|
|
}
|
|
|
|
void defragHash(redisDb *db, dictEntry *kde) {
|
|
robj *ob = dictGetVal(kde);
|
|
dict *d, *newd;
|
|
serverAssert(ob->type == OBJ_HASH && ob->encoding == OBJ_ENCODING_HT);
|
|
d = ob->ptr;
|
|
if (dictSize(d) > server.active_defrag_max_scan_fields)
|
|
defragLater(db, kde);
|
|
else
|
|
activeDefragSdsDict(d, DEFRAG_SDS_DICT_VAL_IS_SDS);
|
|
/* handle the dict struct */
|
|
if ((newd = activeDefragAlloc(ob->ptr)))
|
|
ob->ptr = newd;
|
|
/* defrag the dict tables */
|
|
dictDefragTables(ob->ptr);
|
|
}
|
|
|
|
void defragSet(redisDb *db, dictEntry *kde) {
|
|
robj *ob = dictGetVal(kde);
|
|
dict *d, *newd;
|
|
serverAssert(ob->type == OBJ_SET && ob->encoding == OBJ_ENCODING_HT);
|
|
d = ob->ptr;
|
|
if (dictSize(d) > server.active_defrag_max_scan_fields)
|
|
defragLater(db, kde);
|
|
else
|
|
activeDefragSdsDict(d, DEFRAG_SDS_DICT_NO_VAL);
|
|
/* handle the dict struct */
|
|
if ((newd = activeDefragAlloc(ob->ptr)))
|
|
ob->ptr = newd;
|
|
/* defrag the dict tables */
|
|
dictDefragTables(ob->ptr);
|
|
}
|
|
|
|
/* Defrag callback for radix tree iterator, called for each node,
|
|
* used in order to defrag the nodes allocations. */
|
|
int defragRaxNode(raxNode **noderef) {
|
|
raxNode *newnode = activeDefragAlloc(*noderef);
|
|
if (newnode) {
|
|
*noderef = newnode;
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* returns 0 if no more work needs to be been done, and 1 if time is up and more work is needed. */
|
|
int scanLaterStreamListpacks(robj *ob, unsigned long *cursor, long long endtime) {
|
|
static unsigned char last[sizeof(streamID)];
|
|
raxIterator ri;
|
|
long iterations = 0;
|
|
if (ob->type != OBJ_STREAM || ob->encoding != OBJ_ENCODING_STREAM) {
|
|
*cursor = 0;
|
|
return 0;
|
|
}
|
|
|
|
stream *s = ob->ptr;
|
|
raxStart(&ri,s->rax);
|
|
if (*cursor == 0) {
|
|
/* if cursor is 0, we start new iteration */
|
|
defragRaxNode(&s->rax->head);
|
|
/* assign the iterator node callback before the seek, so that the
|
|
* initial nodes that are processed till the first item are covered */
|
|
ri.node_cb = defragRaxNode;
|
|
raxSeek(&ri,"^",NULL,0);
|
|
} else {
|
|
/* if cursor is non-zero, we seek to the static 'last' */
|
|
if (!raxSeek(&ri,">", last, sizeof(last))) {
|
|
*cursor = 0;
|
|
raxStop(&ri);
|
|
return 0;
|
|
}
|
|
/* assign the iterator node callback after the seek, so that the
|
|
* initial nodes that are processed till now aren't covered */
|
|
ri.node_cb = defragRaxNode;
|
|
}
|
|
|
|
(*cursor)++;
|
|
while (raxNext(&ri)) {
|
|
void *newdata = activeDefragAlloc(ri.data);
|
|
if (newdata)
|
|
raxSetData(ri.node, ri.data=newdata);
|
|
server.stat_active_defrag_scanned++;
|
|
if (++iterations > 128) {
|
|
if (ustime() > endtime) {
|
|
serverAssert(ri.key_len==sizeof(last));
|
|
memcpy(last,ri.key,ri.key_len);
|
|
raxStop(&ri);
|
|
return 1;
|
|
}
|
|
iterations = 0;
|
|
}
|
|
}
|
|
raxStop(&ri);
|
|
*cursor = 0;
|
|
return 0;
|
|
}
|
|
|
|
/* optional callback used defrag each rax element (not including the element pointer itself) */
|
|
typedef void *(raxDefragFunction)(raxIterator *ri, void *privdata);
|
|
|
|
/* defrag radix tree including:
|
|
* 1) rax struct
|
|
* 2) rax nodes
|
|
* 3) rax entry data (only if defrag_data is specified)
|
|
* 4) call a callback per element, and allow the callback to return a new pointer for the element */
|
|
void defragRadixTree(rax **raxref, int defrag_data, raxDefragFunction *element_cb, void *element_cb_data) {
|
|
raxIterator ri;
|
|
rax* rax;
|
|
if ((rax = activeDefragAlloc(*raxref)))
|
|
*raxref = rax;
|
|
rax = *raxref;
|
|
raxStart(&ri,rax);
|
|
ri.node_cb = defragRaxNode;
|
|
defragRaxNode(&rax->head);
|
|
raxSeek(&ri,"^",NULL,0);
|
|
while (raxNext(&ri)) {
|
|
void *newdata = NULL;
|
|
if (element_cb)
|
|
newdata = element_cb(&ri, element_cb_data);
|
|
if (defrag_data && !newdata)
|
|
newdata = activeDefragAlloc(ri.data);
|
|
if (newdata)
|
|
raxSetData(ri.node, ri.data=newdata);
|
|
}
|
|
raxStop(&ri);
|
|
}
|
|
|
|
typedef struct {
|
|
streamCG *cg;
|
|
streamConsumer *c;
|
|
} PendingEntryContext;
|
|
|
|
void* defragStreamConsumerPendingEntry(raxIterator *ri, void *privdata) {
|
|
PendingEntryContext *ctx = privdata;
|
|
streamNACK *nack = ri->data, *newnack;
|
|
nack->consumer = ctx->c; /* update nack pointer to consumer */
|
|
newnack = activeDefragAlloc(nack);
|
|
if (newnack) {
|
|
/* update consumer group pointer to the nack */
|
|
void *prev;
|
|
raxInsert(ctx->cg->pel, ri->key, ri->key_len, newnack, &prev);
|
|
serverAssert(prev==nack);
|
|
}
|
|
return newnack;
|
|
}
|
|
|
|
void* defragStreamConsumer(raxIterator *ri, void *privdata) {
|
|
streamConsumer *c = ri->data;
|
|
streamCG *cg = privdata;
|
|
void *newc = activeDefragAlloc(c);
|
|
if (newc) {
|
|
c = newc;
|
|
}
|
|
sds newsds = activeDefragSds(c->name);
|
|
if (newsds)
|
|
c->name = newsds;
|
|
if (c->pel) {
|
|
PendingEntryContext pel_ctx = {cg, c};
|
|
defragRadixTree(&c->pel, 0, defragStreamConsumerPendingEntry, &pel_ctx);
|
|
}
|
|
return newc; /* returns NULL if c was not defragged */
|
|
}
|
|
|
|
void* defragStreamConsumerGroup(raxIterator *ri, void *privdata) {
|
|
streamCG *cg = ri->data;
|
|
UNUSED(privdata);
|
|
if (cg->consumers)
|
|
defragRadixTree(&cg->consumers, 0, defragStreamConsumer, cg);
|
|
if (cg->pel)
|
|
defragRadixTree(&cg->pel, 0, NULL, NULL);
|
|
return NULL;
|
|
}
|
|
|
|
void defragStream(redisDb *db, dictEntry *kde) {
|
|
robj *ob = dictGetVal(kde);
|
|
serverAssert(ob->type == OBJ_STREAM && ob->encoding == OBJ_ENCODING_STREAM);
|
|
stream *s = ob->ptr, *news;
|
|
|
|
/* handle the main struct */
|
|
if ((news = activeDefragAlloc(s)))
|
|
ob->ptr = s = news;
|
|
|
|
if (raxSize(s->rax) > server.active_defrag_max_scan_fields) {
|
|
rax *newrax = activeDefragAlloc(s->rax);
|
|
if (newrax)
|
|
s->rax = newrax;
|
|
defragLater(db, kde);
|
|
} else
|
|
defragRadixTree(&s->rax, 1, NULL, NULL);
|
|
|
|
if (s->cgroups)
|
|
defragRadixTree(&s->cgroups, 1, defragStreamConsumerGroup, NULL);
|
|
}
|
|
|
|
/* Defrag a module key. This is either done immediately or scheduled
|
|
* for later. Returns then number of pointers defragged.
|
|
*/
|
|
void defragModule(redisDb *db, dictEntry *kde) {
|
|
robj *obj = dictGetVal(kde);
|
|
serverAssert(obj->type == OBJ_MODULE);
|
|
|
|
if (!moduleDefragValue(dictGetKey(kde), obj, db->id))
|
|
defragLater(db, kde);
|
|
}
|
|
|
|
/* for each key we scan in the main dict, this function will attempt to defrag
|
|
* all the various pointers it has. Returns a stat of how many pointers were
|
|
* moved. */
|
|
void defragKey(redisDb *db, dictEntry *de) {
|
|
sds keysds = dictGetKey(de);
|
|
robj *newob, *ob;
|
|
unsigned char *newzl;
|
|
sds newsds;
|
|
|
|
/* Try to defrag the key name. */
|
|
newsds = activeDefragSds(keysds);
|
|
if (newsds) {
|
|
dictSetKey(db->dict, de, newsds);
|
|
if (dictSize(db->expires)) {
|
|
/* We can't search in db->expires for that key after we've released
|
|
* the pointer it holds, since it won't be able to do the string
|
|
* compare, but we can find the entry using key hash and pointer. */
|
|
uint64_t hash = dictGetHash(db->dict, newsds);
|
|
dictEntry *expire_de = dictFindEntryByPtrAndHash(db->expires, keysds, hash);
|
|
if (expire_de) dictSetKey(db->expires, expire_de, newsds);
|
|
}
|
|
}
|
|
|
|
/* Try to defrag robj and / or string value. */
|
|
ob = dictGetVal(de);
|
|
if ((newob = activeDefragStringOb(ob))) {
|
|
dictSetVal(db->dict, de, newob);
|
|
ob = newob;
|
|
}
|
|
|
|
if (ob->type == OBJ_STRING) {
|
|
/* Already handled in activeDefragStringOb. */
|
|
} else if (ob->type == OBJ_LIST) {
|
|
if (ob->encoding == OBJ_ENCODING_QUICKLIST) {
|
|
defragQuicklist(db, de);
|
|
} else if (ob->encoding == OBJ_ENCODING_LISTPACK) {
|
|
if ((newzl = activeDefragAlloc(ob->ptr)))
|
|
ob->ptr = newzl;
|
|
} else {
|
|
serverPanic("Unknown list encoding");
|
|
}
|
|
} else if (ob->type == OBJ_SET) {
|
|
if (ob->encoding == OBJ_ENCODING_HT) {
|
|
defragSet(db, de);
|
|
} else if (ob->encoding == OBJ_ENCODING_INTSET ||
|
|
ob->encoding == OBJ_ENCODING_LISTPACK)
|
|
{
|
|
void *newptr, *ptr = ob->ptr;
|
|
if ((newptr = activeDefragAlloc(ptr)))
|
|
ob->ptr = newptr;
|
|
} else {
|
|
serverPanic("Unknown set encoding");
|
|
}
|
|
} else if (ob->type == OBJ_ZSET) {
|
|
if (ob->encoding == OBJ_ENCODING_LISTPACK) {
|
|
if ((newzl = activeDefragAlloc(ob->ptr)))
|
|
ob->ptr = newzl;
|
|
} else if (ob->encoding == OBJ_ENCODING_SKIPLIST) {
|
|
defragZsetSkiplist(db, de);
|
|
} else {
|
|
serverPanic("Unknown sorted set encoding");
|
|
}
|
|
} else if (ob->type == OBJ_HASH) {
|
|
if (ob->encoding == OBJ_ENCODING_LISTPACK) {
|
|
if ((newzl = activeDefragAlloc(ob->ptr)))
|
|
ob->ptr = newzl;
|
|
} else if (ob->encoding == OBJ_ENCODING_HT) {
|
|
defragHash(db, de);
|
|
} else {
|
|
serverPanic("Unknown hash encoding");
|
|
}
|
|
} else if (ob->type == OBJ_STREAM) {
|
|
defragStream(db, de);
|
|
} else if (ob->type == OBJ_MODULE) {
|
|
defragModule(db, de);
|
|
} else {
|
|
serverPanic("Unknown object type");
|
|
}
|
|
}
|
|
|
|
/* Defrag scan callback for the main db dictionary. */
|
|
void defragScanCallback(void *privdata, const dictEntry *de) {
|
|
long long hits_before = server.stat_active_defrag_hits;
|
|
defragKey((redisDb*)privdata, (dictEntry*)de);
|
|
if (server.stat_active_defrag_hits != hits_before)
|
|
server.stat_active_defrag_key_hits++;
|
|
else
|
|
server.stat_active_defrag_key_misses++;
|
|
server.stat_active_defrag_scanned++;
|
|
}
|
|
|
|
/* Utility function to get the fragmentation ratio from jemalloc.
|
|
* It is critical to do that by comparing only heap maps that belong to
|
|
* jemalloc, and skip ones the jemalloc keeps as spare. Since we use this
|
|
* fragmentation ratio in order to decide if a defrag action should be taken
|
|
* or not, a false detection can cause the defragmenter to waste a lot of CPU
|
|
* without the possibility of getting any results. */
|
|
float getAllocatorFragmentation(size_t *out_frag_bytes) {
|
|
size_t resident, active, allocated;
|
|
zmalloc_get_allocator_info(&allocated, &active, &resident);
|
|
float frag_pct = ((float)active / allocated)*100 - 100;
|
|
size_t frag_bytes = active - allocated;
|
|
float rss_pct = ((float)resident / allocated)*100 - 100;
|
|
size_t rss_bytes = resident - allocated;
|
|
if(out_frag_bytes)
|
|
*out_frag_bytes = frag_bytes;
|
|
serverLog(LL_DEBUG,
|
|
"allocated=%zu, active=%zu, resident=%zu, frag=%.0f%% (%.0f%% rss), frag_bytes=%zu (%zu rss)",
|
|
allocated, active, resident, frag_pct, rss_pct, frag_bytes, rss_bytes);
|
|
return frag_pct;
|
|
}
|
|
|
|
/* We may need to defrag other globals, one small allocation can hold a full allocator run.
|
|
* so although small, it is still important to defrag these */
|
|
void defragOtherGlobals(void) {
|
|
|
|
/* there are many more pointers to defrag (e.g. client argv, output / aof buffers, etc.
|
|
* but we assume most of these are short lived, we only need to defrag allocations
|
|
* that remain static for a long time */
|
|
activeDefragSdsDict(evalScriptsDict(), DEFRAG_SDS_DICT_VAL_LUA_SCRIPT);
|
|
moduleDefragGlobals();
|
|
}
|
|
|
|
/* returns 0 more work may or may not be needed (see non-zero cursor),
|
|
* and 1 if time is up and more work is needed. */
|
|
int defragLaterItem(dictEntry *de, unsigned long *cursor, long long endtime, int dbid) {
|
|
if (de) {
|
|
robj *ob = dictGetVal(de);
|
|
if (ob->type == OBJ_LIST) {
|
|
return scanLaterList(ob, cursor, endtime);
|
|
} else if (ob->type == OBJ_SET) {
|
|
scanLaterSet(ob, cursor);
|
|
} else if (ob->type == OBJ_ZSET) {
|
|
scanLaterZset(ob, cursor);
|
|
} else if (ob->type == OBJ_HASH) {
|
|
scanLaterHash(ob, cursor);
|
|
} else if (ob->type == OBJ_STREAM) {
|
|
return scanLaterStreamListpacks(ob, cursor, endtime);
|
|
} else if (ob->type == OBJ_MODULE) {
|
|
return moduleLateDefrag(dictGetKey(de), ob, cursor, endtime, dbid);
|
|
} else {
|
|
*cursor = 0; /* object type may have changed since we schedule it for later */
|
|
}
|
|
} else {
|
|
*cursor = 0; /* object may have been deleted already */
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* static variables serving defragLaterStep to continue scanning a key from were we stopped last time. */
|
|
static sds defrag_later_current_key = NULL;
|
|
static unsigned long defrag_later_cursor = 0;
|
|
|
|
/* returns 0 if no more work needs to be been done, and 1 if time is up and more work is needed. */
|
|
int defragLaterStep(redisDb *db, long long endtime) {
|
|
unsigned int iterations = 0;
|
|
unsigned long long prev_defragged = server.stat_active_defrag_hits;
|
|
unsigned long long prev_scanned = server.stat_active_defrag_scanned;
|
|
long long key_defragged;
|
|
|
|
do {
|
|
/* if we're not continuing a scan from the last call or loop, start a new one */
|
|
if (!defrag_later_cursor) {
|
|
listNode *head = listFirst(db->defrag_later);
|
|
|
|
/* Move on to next key */
|
|
if (defrag_later_current_key) {
|
|
serverAssert(defrag_later_current_key == head->value);
|
|
listDelNode(db->defrag_later, head);
|
|
defrag_later_cursor = 0;
|
|
defrag_later_current_key = NULL;
|
|
}
|
|
|
|
/* stop if we reached the last one. */
|
|
head = listFirst(db->defrag_later);
|
|
if (!head)
|
|
return 0;
|
|
|
|
/* start a new key */
|
|
defrag_later_current_key = head->value;
|
|
defrag_later_cursor = 0;
|
|
}
|
|
|
|
/* each time we enter this function we need to fetch the key from the dict again (if it still exists) */
|
|
dictEntry *de = dictFind(db->dict, defrag_later_current_key);
|
|
key_defragged = server.stat_active_defrag_hits;
|
|
do {
|
|
int quit = 0;
|
|
if (defragLaterItem(de, &defrag_later_cursor, endtime,db->id))
|
|
quit = 1; /* time is up, we didn't finish all the work */
|
|
|
|
/* Once in 16 scan iterations, 512 pointer reallocations, or 64 fields
|
|
* (if we have a lot of pointers in one hash bucket, or rehashing),
|
|
* check if we reached the time limit. */
|
|
if (quit || (++iterations > 16 ||
|
|
server.stat_active_defrag_hits - prev_defragged > 512 ||
|
|
server.stat_active_defrag_scanned - prev_scanned > 64)) {
|
|
if (quit || ustime() > endtime) {
|
|
if(key_defragged != server.stat_active_defrag_hits)
|
|
server.stat_active_defrag_key_hits++;
|
|
else
|
|
server.stat_active_defrag_key_misses++;
|
|
return 1;
|
|
}
|
|
iterations = 0;
|
|
prev_defragged = server.stat_active_defrag_hits;
|
|
prev_scanned = server.stat_active_defrag_scanned;
|
|
}
|
|
} while(defrag_later_cursor);
|
|
if(key_defragged != server.stat_active_defrag_hits)
|
|
server.stat_active_defrag_key_hits++;
|
|
else
|
|
server.stat_active_defrag_key_misses++;
|
|
} while(1);
|
|
}
|
|
|
|
#define INTERPOLATE(x, x1, x2, y1, y2) ( (y1) + ((x)-(x1)) * ((y2)-(y1)) / ((x2)-(x1)) )
|
|
#define LIMIT(y, min, max) ((y)<(min)? min: ((y)>(max)? max: (y)))
|
|
|
|
/* decide if defrag is needed, and at what CPU effort to invest in it */
|
|
void computeDefragCycles(void) {
|
|
size_t frag_bytes;
|
|
float frag_pct = getAllocatorFragmentation(&frag_bytes);
|
|
/* If we're not already running, and below the threshold, exit. */
|
|
if (!server.active_defrag_running) {
|
|
if(frag_pct < server.active_defrag_threshold_lower || frag_bytes < server.active_defrag_ignore_bytes)
|
|
return;
|
|
}
|
|
|
|
/* Calculate the adaptive aggressiveness of the defrag */
|
|
int cpu_pct = INTERPOLATE(frag_pct,
|
|
server.active_defrag_threshold_lower,
|
|
server.active_defrag_threshold_upper,
|
|
server.active_defrag_cycle_min,
|
|
server.active_defrag_cycle_max);
|
|
cpu_pct = LIMIT(cpu_pct,
|
|
server.active_defrag_cycle_min,
|
|
server.active_defrag_cycle_max);
|
|
/* We allow increasing the aggressiveness during a scan, but don't
|
|
* reduce it. */
|
|
if (cpu_pct > server.active_defrag_running) {
|
|
server.active_defrag_running = cpu_pct;
|
|
serverLog(LL_VERBOSE,
|
|
"Starting active defrag, frag=%.0f%%, frag_bytes=%zu, cpu=%d%%",
|
|
frag_pct, frag_bytes, cpu_pct);
|
|
}
|
|
}
|
|
|
|
/* Perform incremental defragmentation work from the serverCron.
|
|
* This works in a similar way to activeExpireCycle, in the sense that
|
|
* we do incremental work across calls. */
|
|
void activeDefragCycle(void) {
|
|
static int current_db = -1;
|
|
static unsigned long cursor = 0;
|
|
static unsigned long expires_cursor = 0;
|
|
static redisDb *db = NULL;
|
|
static long long start_scan, start_stat;
|
|
unsigned int iterations = 0;
|
|
unsigned long long prev_defragged = server.stat_active_defrag_hits;
|
|
unsigned long long prev_scanned = server.stat_active_defrag_scanned;
|
|
long long start, timelimit, endtime;
|
|
mstime_t latency;
|
|
int quit = 0;
|
|
|
|
if (!server.active_defrag_enabled) {
|
|
if (server.active_defrag_running) {
|
|
/* if active defrag was disabled mid-run, start from fresh next time. */
|
|
server.active_defrag_running = 0;
|
|
if (db)
|
|
listEmpty(db->defrag_later);
|
|
defrag_later_current_key = NULL;
|
|
defrag_later_cursor = 0;
|
|
current_db = -1;
|
|
cursor = 0;
|
|
db = NULL;
|
|
goto update_metrics;
|
|
}
|
|
return;
|
|
}
|
|
|
|
if (hasActiveChildProcess())
|
|
return; /* Defragging memory while there's a fork will just do damage. */
|
|
|
|
/* Once a second, check if the fragmentation justfies starting a scan
|
|
* or making it more aggressive. */
|
|
run_with_period(1000) {
|
|
computeDefragCycles();
|
|
}
|
|
if (!server.active_defrag_running)
|
|
return;
|
|
|
|
/* See activeExpireCycle for how timelimit is handled. */
|
|
start = ustime();
|
|
timelimit = 1000000*server.active_defrag_running/server.hz/100;
|
|
if (timelimit <= 0) timelimit = 1;
|
|
endtime = start + timelimit;
|
|
latencyStartMonitor(latency);
|
|
|
|
dictDefragFunctions defragfns = {.defragAlloc = activeDefragAlloc};
|
|
do {
|
|
/* if we're not continuing a scan from the last call or loop, start a new one */
|
|
if (!cursor && !expires_cursor) {
|
|
/* finish any leftovers from previous db before moving to the next one */
|
|
if (db && defragLaterStep(db, endtime)) {
|
|
quit = 1; /* time is up, we didn't finish all the work */
|
|
break; /* this will exit the function and we'll continue on the next cycle */
|
|
}
|
|
|
|
/* Move on to next database, and stop if we reached the last one. */
|
|
if (++current_db >= server.dbnum) {
|
|
/* defrag other items not part of the db / keys */
|
|
defragOtherGlobals();
|
|
|
|
long long now = ustime();
|
|
size_t frag_bytes;
|
|
float frag_pct = getAllocatorFragmentation(&frag_bytes);
|
|
serverLog(LL_VERBOSE,
|
|
"Active defrag done in %dms, reallocated=%d, frag=%.0f%%, frag_bytes=%zu",
|
|
(int)((now - start_scan)/1000), (int)(server.stat_active_defrag_hits - start_stat), frag_pct, frag_bytes);
|
|
|
|
start_scan = now;
|
|
current_db = -1;
|
|
cursor = 0;
|
|
db = NULL;
|
|
server.active_defrag_running = 0;
|
|
|
|
computeDefragCycles(); /* if another scan is needed, start it right away */
|
|
if (server.active_defrag_running != 0 && ustime() < endtime)
|
|
continue;
|
|
break;
|
|
}
|
|
else if (current_db==0) {
|
|
/* Start a scan from the first database. */
|
|
start_scan = ustime();
|
|
start_stat = server.stat_active_defrag_hits;
|
|
}
|
|
|
|
db = &server.db[current_db];
|
|
cursor = 0;
|
|
}
|
|
|
|
do {
|
|
/* before scanning the next bucket, see if we have big keys left from the previous bucket to scan */
|
|
if (defragLaterStep(db, endtime)) {
|
|
quit = 1; /* time is up, we didn't finish all the work */
|
|
break; /* this will exit the function and we'll continue on the next cycle */
|
|
}
|
|
|
|
/* Scan the keyspace dict unless we're scanning the expire dict. */
|
|
if (!expires_cursor)
|
|
cursor = dictScanDefrag(db->dict, cursor, defragScanCallback,
|
|
&defragfns, db);
|
|
|
|
/* When done scanning the keyspace dict, we scan the expire dict. */
|
|
if (!cursor)
|
|
expires_cursor = dictScanDefrag(db->expires, expires_cursor,
|
|
scanCallbackCountScanned,
|
|
&defragfns, NULL);
|
|
|
|
/* Once in 16 scan iterations, 512 pointer reallocations. or 64 keys
|
|
* (if we have a lot of pointers in one hash bucket or rehashing),
|
|
* check if we reached the time limit.
|
|
* But regardless, don't start a new db in this loop, this is because after
|
|
* the last db we call defragOtherGlobals, which must be done in one cycle */
|
|
if (!(cursor || expires_cursor) ||
|
|
++iterations > 16 ||
|
|
server.stat_active_defrag_hits - prev_defragged > 512 ||
|
|
server.stat_active_defrag_scanned - prev_scanned > 64)
|
|
{
|
|
if (!cursor || ustime() > endtime) {
|
|
quit = 1;
|
|
break;
|
|
}
|
|
iterations = 0;
|
|
prev_defragged = server.stat_active_defrag_hits;
|
|
prev_scanned = server.stat_active_defrag_scanned;
|
|
}
|
|
} while((cursor || expires_cursor) && !quit);
|
|
} while(!quit);
|
|
|
|
latencyEndMonitor(latency);
|
|
latencyAddSampleIfNeeded("active-defrag-cycle",latency);
|
|
|
|
update_metrics:
|
|
if (server.active_defrag_running > 0) {
|
|
if (server.stat_last_active_defrag_time == 0)
|
|
elapsedStart(&server.stat_last_active_defrag_time);
|
|
} else if (server.stat_last_active_defrag_time != 0) {
|
|
server.stat_total_active_defrag_time += elapsedUs(server.stat_last_active_defrag_time);
|
|
server.stat_last_active_defrag_time = 0;
|
|
}
|
|
}
|
|
|
|
#else /* HAVE_DEFRAG */
|
|
|
|
void activeDefragCycle(void) {
|
|
/* Not implemented yet. */
|
|
}
|
|
|
|
void *activeDefragAlloc(void *ptr) {
|
|
UNUSED(ptr);
|
|
return NULL;
|
|
}
|
|
|
|
robj *activeDefragStringOb(robj *ob) {
|
|
UNUSED(ob);
|
|
return NULL;
|
|
}
|
|
|
|
#endif
|