From 402053e9fe5a42f73c6146718f6f1316251998f2 Mon Sep 17 00:00:00 2001 From: antirez Date: Mon, 15 Jan 2018 12:50:08 +0100 Subject: [PATCH] Put more details in the comment introduced by #4601. --- src/lazyfree.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/src/lazyfree.c b/src/lazyfree.c index cfab6a31a..f1de0c898 100644 --- a/src/lazyfree.c +++ b/src/lazyfree.c @@ -64,9 +64,14 @@ int dbAsyncDelete(redisDb *db, robj *key) { robj *val = dictGetVal(de); size_t free_effort = lazyfreeGetFreeEffort(val); - /* If releasing the object is too much work and the refcount - * is 1, that means the object really needs to be freed, - * let's put it into the lazy free list. */ + /* If releasing the object is too much work, do it in the background + * by adding the object to the lazy free list. + * Note that if the object is shared, to reclaim it now it is not + * possible. This rarely happens, however sometimes the implementation + * of parts of the Redis core may call incrRefCount() to protect + * objects, and then call dbDelete(). In this case we'll fall + * through and reach the dictFreeUnlinkedEntry() call, that will be + * equivalent to just calling decrRefCount(). */ if (free_effort > LAZYFREE_THRESHOLD && val->refcount == 1) { atomicIncr(lazyfree_objects,1); bioCreateBackgroundJob(BIO_LAZY_FREE,val,NULL,NULL);