## +21 ## Hazard Pointer Synchronous Reclamation Beyond Concurrency TS2 ## MAGED MICHAEL ## Basic Hazard Pointer Algorithm Hazard pointers protect access to objects that may be removed concurrently A hazard pointer is a single-writer multi-reader pointer. If a hazard pointer points to an object before its removal, then the object will not be reclaimed as long as the hazard pointer remains unchanged _3.jpg)  read pointer A from SRC SRC $$ ^{*}A $$ ![Image](/uploads/documents/1/7/5/a/175a94ae744d634a4a2d21a0d05b187f/p2_5

Restore, Then More! ## EDUARDO MADRID ## 2024 September 15 - 20 ## Let's do the opposite of pointer chasing Alternative title ## What's what we mean to improve? • Our systems need objects to refer arrays • ...word salad? ## Row-wise representation Heterogeneous (different) data types int id; Pointer. Can it be null? Optional? double price; Specials *specials; Category *category; bool is_homemade;

[Image](/uploads/documents/e/3/e/5/e3e5a86d3059a072f18863b1893028ed/p15_1.jpg) Not cache friendly. A lot of pointer chasing especially when load factor is high. ## 1 ## Unordered Map  Not cache friendly. A lot of pointer chasing especially when load factor is high.  Not cache friendly. A lot of pointer chasing especially when load factor is high. ![Image](/uploads/documents/e/3/e/5/e3e5a86d3059a072f1

Client (“mutator”) accesses must be memory_order_relaxed for performance. • Collector relies on pointer validity to avoid undefined-behavior. “Chaotic relaxation” numerical algorithms with no synchronization not be an elegant OOTA fix" Closely related: “quantum atomics” in Sinclair, Alsop, and Adve, “Chasing Away Rats: Semantics and Evaluation for Relaxed Atomics on Heterogeneous Systems” A proposal to

the DavGenericLockDB directive described below. ## Developer's Note In order to retrieve the pointer to the locking provider function, you have to use the ap_lookup_provider API with the arguments dav-lock These credentials can be provided to LDAP servers that do not allow anonymous binds during referral chasing. To control this feature, see the LDAPReferrals and LDAPReferralHopLimit directives. By default, this tunable is uncommon in LDAP SDKs. ## LDAPReferrals Directive |Description:|Enable referral chasing during queries to the LDAP server.| |---|---| |Syntax:|LDAPReferrals On \| Off \| default| |Default:|LDAPReferrals

the DavGenericLockDB directive described below. ## Developer's Note In order to retrieve the pointer to the locking provider function, you have to use the ap_lookup_provider API with the arguments dav-lock These credentials can be provided to LDAP servers that do not allow anonymous binds during referral chasing. To control this feature, see the LDAPReferrals and LDAPReferralHopLimit directives. By default, this tunable is uncommon in LDAP SDKs. LDAPReferrals Directive |Description:|Enable referral chasing during queries to the LDAP server.| |---|---| |Syntax:|LDAPReferrals On \| Off \| default| |Default:|LDAPReferrals

the DavGenericLockDB directive described below. ## Developer's Note In order to retrieve the pointer to the locking provider function, you have to use the ap_lookup_provider API with the arguments dav-lock These credentials can be provided to LDAP servers that do not allow anonymous binds during referral chasing. To control this feature, see the LDAPReferrals and LDAPReferralHopLimit directives. By default, this tunable is uncommon in LDAP SDKs. LDAPReferrals Directive |Description:|Enable referral chasing during queries to the LDAP server.| |---|---| |Syntax:|LDAPReferrals On \| Off \| default| |Default:|LDAPReferrals

the DavGenericLockDB directive described below. ## Developer's Note In order to retrieve the pointer to the locking provider function, you have to use the ap_lookup_provider API with the arguments dav-lock These credentials can be provided to LDAP servers that do not allow anonymous binds during referral chasing. To control this feature, see the LDAPReferrals and LDAPReferralHopLimit directives. By default, this tunable is uncommon in LDAP SDKs. LDAPReferrals Directive |Description:|Enable referral chasing during queries to the LDAP server.| |---|---| |Syntax:|LDAPReferrals On \| Off \| default| |Default:|LDAPReferrals

the DavGenericLockDB directive described below. ## Developer's Note In order to retrieve the pointer to the locking provider function, you have to use the ap_lookup_provider API with the arguments dav-lock These credentials can be provided to LDAP servers that do not allow anonymous binds during referral chasing. To control this feature, see the LDAPReferrals and LDAPReferralHopLimit directives. By default, this tunable is uncommon in LDAP SDKs. LDAPReferrals Directive |Description:|Enable referral chasing during queries to the LDAP server.| |---|---| |Syntax:|LDAPReferrals On \| Off \| default| |Default:|LDAPReferrals

the DavGenericLockDB directive described below. ## Developer's Note In order to retrieve the pointer to the locking provider function, you have to use the ap_lookup_provider API with the arguments dav-lock These credentials can be provided to LDAP servers that do not allow anonymous binds during referral chasing. To control this feature, see the LDAPReferrals and LDAPReferralHopLimit directives. By default, this tunable is uncommon in LDAP SDKs. ## LDAPReferrals Directive |Description:|Enable referral chasing during queries to the LDAP server.| |---|---| |Syntax:|LDAPReferrals On \| Off \| default| |Default:|LDAPReferrals