From 2c56e7dc08a41fc1dfa6a79213e93686f553847c Mon Sep 17 00:00:00 2001 From: William Brown Date: Mon, 11 Dec 2017 15:48:24 +0100 Subject: [PATCH] Ticket 49495 - Fix memory management is vattr. Bug Description: During the fix for https://pagure.io/389-ds-base/issue/49436 a issue was exposed in how registration of attributes to cos work. With the change to handle -> attr link, this exposed that cos treats each attribute and template pair as a new type for the handle. As aresult, this caused the sp_list to create a long linked list of M*N entries for each attr - template value. Obviously, this is extremely slow to traverse during a search! Fix Description: Undo part of the SLL next change and convert to reference counting. The issue remains that there is a defect in how cos handles attribute registration, but this can not be resolved without a significant rearchitecture of the code related to virtual attributes. https://pagure.io/389-ds-base/issue/49495 Author: wibrown Review by: tbordaz, lkrispen (Thanks!) --- ldap/servers/plugins/cos/cos_cache.c | 28 +++++++++++----------------- ldap/servers/slapd/vattr.c | 23 +++++++++++++++++++++-- 2 files changed, 32 insertions(+), 19 deletions(-) diff --git a/ldap/servers/plugins/cos/cos_cache.c b/ldap/servers/plugins/cos/cos_cache.c index 662dace35..3b3c05783 100644 --- a/ldap/servers/plugins/cos/cos_cache.c +++ b/ldap/servers/plugins/cos/cos_cache.c @@ -275,7 +275,7 @@ static Slapi_Mutex *start_lock; static Slapi_Mutex *stop_lock; static Slapi_CondVar *something_changed = NULL; static Slapi_CondVar *start_cond = NULL; - +static vattr_sp_handle *vattr_handle = NULL; /* cos_cache_init @@ -314,6 +314,15 @@ cos_cache_init(void) goto out; } + if (slapi_vattrspi_register((vattr_sp_handle **)&vattr_handle, + cos_cache_vattr_get, + cos_cache_vattr_compare, + cos_cache_vattr_types) != 0) { + slapi_log_err(SLAPI_LOG_ERR, COS_PLUGIN_SUBSYSTEM, "cos_cache_init - Cannot register as service provider\n"); + ret = -1; + goto out; + } + /* grab the views interface */ if (slapi_apib_get_interface(Views_v1_0_GUID, &views_api)) { /* lets be tolerant if views is disabled */ @@ -847,22 +856,7 @@ cos_dn_defs_cb(Slapi_Entry *e, void *callback_data) dnVals[valIndex]->bv_val); } - /* - * Each SP_handle is associated to one and only one vattr. - * We could consider making this a single function rather - * than the double-call. - */ - - vattr_sp_handle *vattr_handle = NULL; - - if (slapi_vattrspi_register((vattr_sp_handle **)&vattr_handle, - cos_cache_vattr_get, - cos_cache_vattr_compare, - cos_cache_vattr_types) != 0) { - slapi_log_err(SLAPI_LOG_ERR, COS_PLUGIN_SUBSYSTEM, "cos_cache_init - Cannot register as service provider for %s\n", dnVals[valIndex]->bv_val); - } else { - slapi_vattrspi_regattr((vattr_sp_handle *)vattr_handle, dnVals[valIndex]->bv_val, NULL, NULL); - } + slapi_vattrspi_regattr((vattr_sp_handle *)vattr_handle, dnVals[valIndex]->bv_val, NULL, NULL); } /* if(attrType is cosAttribute) */ diff --git a/ldap/servers/slapd/vattr.c b/ldap/servers/slapd/vattr.c index 432946c79..13e527188 100644 --- a/ldap/servers/slapd/vattr.c +++ b/ldap/servers/slapd/vattr.c @@ -1544,6 +1544,7 @@ struct _vattr_sp_handle vattr_sp *sp; struct _vattr_sp_handle *next; /* So we can link them together in the map */ void *hint; /* Hint to the SP */ + uint64_t rc; }; /* Calls made by Service Providers */ @@ -1770,7 +1771,7 @@ is a separate thing in the insterests of stability. */ -#define VARRT_MAP_HASHTABLE_SIZE 10 +#define VARRT_MAP_HASHTABLE_SIZE 32 /* Attribute map oject */ /* Needs to contain: a linked list of pointers to provider handles handles, @@ -1867,7 +1868,10 @@ vattr_map_entry_free(vattr_map_entry *vae) vattr_sp_handle *list_entry = vae->sp_list; while (list_entry != NULL) { vattr_sp_handle *next_entry = list_entry->next; - slapi_ch_free((void **)&list_entry); + if (slapi_atomic_decr_64(&(list_entry->rc), __ATOMIC_RELAXED) == 0) { + /* Only free on RC 0 */ + slapi_ch_free((void **)&list_entry); + } list_entry = next_entry; } slapi_ch_free_string(&(vae->type_name)); @@ -2280,6 +2284,17 @@ to handle the calls on it, but return nothing */ * * Better idea, is that regattr should just take the fn pointers * and callers never *see* the sp_handle structure at all. + * + * This leaves us with some quirks today. First: if you have plugin A + * and B, A registers attr 1 and B 1 and 2, it's possible that if you + * register A1 first, then B1, you have B->A in next. Then when you + * register B2, because we take 0==result from map_lookup, we add sp + * "as is" to the map. This means that B2 now has the same next to A1 + * handle. This won't add a bug, because A1 won't be able to service the + * attr, but it could cause some head scratching ... + * + * Again, to fix this, the whole vattr external interface needs a + * redesign ... :( */ int @@ -2304,11 +2319,15 @@ vattr_map_sp_insert(char *type_to_add, vattr_sp_handle *sp, void *hint) if (found) { return 0; } + /* Increase the ref count of the sphandle */ + slapi_atomic_incr_64(&(sp->rc), __ATOMIC_RELAXED); /* We insert the SP handle into the linked list at the head */ sp->next = map_entry->sp_list; map_entry->sp_list = sp; } else { /* If not, add it */ + /* Claim a reference on the sp ... */ + slapi_atomic_incr_64(&(sp->rc), __ATOMIC_RELAXED); map_entry = vattr_map_entry_new(type_to_add, sp, hint); if (NULL == map_entry) { return ENOMEM; -- 2.13.6