deadlock research paper

A Survey of Deadlock Detection Algorithms

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• First Online: 31 March 2022
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• Palak Vij 40 ,
• Sayali Nikam 40 &
• Amit Dua 40  

Part of the book series: Lecture Notes in Electrical Engineering ((LNEE,volume 840))

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A deadlock is a situation in which two processes which share the identical resource are dependent on one another and prevents each other from accessing resources, which results in both programs ceasing to function. The formation of deadlock reduces the system efficiency. Thus, to avoid performance degradation due to deadlock, it is necessary that a system should be exempted from deadlock or that deadlocks be quickly diagnosed and abolished. We propose a survey on different deadlock identification and resolution techniques. Various algorithms for identifying deadlocks and handling strategies have been proposed till now. In this paper, we represent a comparative study among different strategies used to diagnose and resolve deadlocks in various environments using different parameters.

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Birla Institute of Technology and Science, Pilani, India

Palak Vij, Sayali Nikam & Amit Dua

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Correspondence to Amit Dua .

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Department of Computer Science, CHRIST (Deemed to be University), Bengaluru, Karnataka, India

Sagaya Aurelia

Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai, Tamil Nadu, India

Somashekhar S. Hiremath

Department of Information Technology, University of Technology and Applied Science, Sultanate of Oman, Oman

Karthikeyan Subramanian

Department of Computer Science Engineering, National Institute of Technology Silchar, Silchar, Assam, India

Saroj Kr. Biswas

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Vij, P., Nikam, S., Dua, A. (2022). A Survey of Deadlock Detection Algorithms. In: Aurelia, S., Hiremath, S.S., Subramanian, K., Biswas, S.K. (eds) Sustainable Advanced Computing. Lecture Notes in Electrical Engineering, vol 840. Springer, Singapore. https://doi.org/10.1007/978-981-16-9012-9_51

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Deadlock detection in distributed databases

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The problem of deadlock detection in distributed systems has undergone extensive study. An important application relates to distributed database systems. A uniform model in which published algorithms can be cast is given, and the fundamental principles on which distributed deadlock detection schemes are based are presented. These principles represent mechanisms for developing distributed algorithms in general and deadlock detection schemes in particular. In addition, a hierarchy of deadlock models is presented; each model is characterized by the restrictions that are imposed upon the form resource requests can assume. The hierarchy includes the well-known models of resource and communication deadlock. Algorithms are classified according to both the underlying principles and the generality of resource requests they permit. A number of algorithms are discussed in detail, and their complexity in terms of the number of messages employed is compared. The point is made that correctness proofs for such algorithms using operational arguments are cumbersome and error prone and, therefore, that only completely formal proofs are sufficient for demonstrating correctness.

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Reviewer: Gerard J. Holzmann

This readable and instructive paper focuses on algorithms for deadlock detection, rather than deadlock prevention or resolution. Knapp begins by formulating a general model for resource allocation in distributed systems, distinguishing between six different models of increasing generality. In the simplest model, any process within the system may request and monopolize no more than one resource at a time, while in the most general model, all possible variants of overlapping requests for multiple resources are permitted. The types of deadlock that can result in each type of system are different, and the complexity of the required deadlock detection algorithms also differs. Knapp classifies deadlock detection algorithms into four main types: (1) path-pushing algorithms, (2) edge-chasing algorithms, (3) diffusing computations, and (4) global state detection algorithms. In a path-pushing algorithm, for instance, the processes exchange complete information about the resources they are waiting for. Each process is then able to construct a wait-for-graph of the system as a whole and detect the deadlock configurations. Knapp writes: “One noteworthy point about path-pushing algorithms is that many of them were found to be incorrect, either by not detecting true deadlocks, by discovering phantom deadlocks, or both.” Knapp gives a sufficient number of examples of published and “proved” algorithms to validate his claim. In an edge-chasing algorithm, the processes can issue special messages called probes. A probe message is forwarded to all processes that the receiving process waits for. A deadlock can be declared if a probe message makes its way back to the originating process. As an example of a simple and well-designed algorithm of this type, the author discusses in some detail the work of Mitchell and Merritt [1]. Their algorithm has the added advantage that the proofs of correctness are elegant and, says Knapp, “fun to read (and write).” The last two types of algorithms, diffusing computations and global state detection, are based on early work by Dijkstra and Lamport, respectively. Knapp gives detailed motivations and examples of each type of algorithm. One of Knapp's conclusions is particularly worth quoting: “The large number of errors in published algorithms addressing the problem of distributed deadlock detection . . . shows that only rigorous proofs, using as little operational argumentation as possible, suffice to show the correctness of these algorithms.” Some of these errors have escaped notice for many years. This paper is a laudable attempt to set the record straight.

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• DOI: 10.1109/MC.1980.1653786
• Corpus ID: 8625906

The Deadlock Problem: An Overview

• Sreekaanth S. Isloor , T. Marsland
• Published in Computer 1 September 1980
• Computer Science

Figures and Tables from this paper

96 Citations

Related work on deadlock and termination detection techniques, deadlock detection in distributed systems, using ordered and atomic multicast for distributed deadlock prevention, prevention of deadlocks in packet-switched data transport systems, an o(n) distributed deadlock resolution algorithm, a simple distributed deadlock detection algorithm, a survey of distributed deadlock detection algorithms, a protocol for resource locking and deadlock detection in a multi-user environment, protocols for deadlock detection in distributed database systems, a partially distributed deadlock detection algorithm, 92 references, avoiding deadlock in distributed data bases, deadlock detection in computer networks, system deadlocks, a practical deadlock avoidance algorithm for data base systems, avoiding deadlock in multitasking systems, access synthronization and deadlock-analysis in database systems: an implementation-oriented approach, a polynomial-time test for the deadlock-freedom of computer systems, concurrency in database systems: a simulation study, comments on prevention of system deadlocks, on deadlock in computer systems, related papers.

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Peahen: Fast and Precise Static Deadlock Detection via Context Reduction

Program display configuration.

Deadlocks still severely inflict reliability and security issues upon software systems of the modern age. Worse still, as we note, in prior static deadlock detectors, good precision does not go hand-in-hand with high scalability — their approaches are either context-insensitive, thereby engendering many false positives, or suffer from the calling context explosion to reach context-sensitive, thus compromising good efficiency. In this paper, we advocate Peahen, geared towards precise yet also scalable static deadlock detection. At its crux, Peahen decomposes the computational effort for embracing high precision into two cooperative analysis stages: (i) context-insensitive lock-graph construction, which selectively encodes the essential lock-acquisition information on each edge, and (ii) three precise yet lazy refinements, which incorporate such edge information into progressively refining the deadlock cycles in the lock graph only for a few interesting calling contexts.

Our extensive experiments yield promising results: Peahen dramatically out-performs the state-of-the-art tools on accuracy without losing scalability; it can efficiently check million-line systems at a low false positive rate; and it has uncovered many confirmed deadlocks in dozens of mature open-source systems.

Yuandao Cai

Hong kong university of science and technology.

Chengfeng Ye

Qingkai Shi

Purdue university, united states.

Charles Zhang

Wed 16 nov displayed time zone: beijing, chongqing, hong kong, urumqi change.

An Experimental Execution Of Deadlock Algorithms

Proceedings of the International Conference on Innovative Computing & Communication (ICICC) 2021

6 Pages Posted: 23 Apr 2021

Karthik Konar

NMIMS Mukesh Patel School of Technology Management & Engineering

Riddhi Patel

Date Written: December 13, 2020

A deadlock condition occurs when a set of processes requests the same resource which is currently being held/allocated to some other processes. The process which is in deadlock state will wait for a large amount of time and they will never terminate their executions and the resources which are held by that set of processes cannot be made available to any other processes which may sometimes lead to a system failure. There are methods for handling deadlocks such as deadlock prevention or avoidance, ignoring the problem altogether, and deadlock detection and recovery. Also, various conditions may help prevent deadlock to some extent but to completely eradicate deadlock from the system an efficient operating system needs to be developed with efficient synchronization algorithms. In this paper we have provided a practical implementation of deadlock scenario as well as deadlock concepts which includes Mutual Exclusion, Hold and Wait, No Preemption, Circular Wait, Process Termination, Selecting Victim, Rollback, and starvation. Java Programming language is utilized for developing all algorithms which we have presented in this paper.

Keywords: Deadlock Implementation, Mutual Exclusion, Hold and Wait, Starvation, Roll Back, Process Termination, Circular Wait, No Preemption, Selecting A Victim

Suggested Citation: Suggested Citation

Karthik Konar (Contact Author)

Nmims mukesh patel school of technology management & engineering ( email ).

Mumbai India

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Deadlocks detection in multithreaded applications based on source code analysis.

1. Introduction

1.1. resource conflict and deadlock definition, 1.2. the structure of the article, 2. thread synchronisation mechanisms.

• PTHREAD_MUTEX_NORMAL (PMN)
• PTHREAD_MUTEX_ERRORCHECK (PME)
• PTHREAD_MUTEX_RECURSIVE (PMR)
• PTHREAD_MUTEX_DEFAULT (PMD)

2.2. Condition Variables

3. multithreaded application source code model.

• P is the application index,
• T P = { t i | i = 0 … α }, ( α ∈ N ) is a set of t i threads of C P application, where t 0 is the main thread, | T P | > 1 ,
• U P = ( u b | b = 1 … β ) , ( β ∈ N + ) is u b sequence of sets that are subsets of T P set containing threads working in the same time interval in C P application, with | U P | > 2 , u 1 = { t 0 } i u β = { t 0 } ,
• R P = { r c | c = 1 … γ } , r c = { v 1 , v 2 , … , v η } , ( γ , η ∈ N + ) is a set of shared resources of C P application, and the next elements are sets of names of variables related to a single resource,
• O P = { o i , j | i = 1 … δ , j = 1 … ϵ } , ( δ , ϵ , ∈ N + ) is a set of all C P application operations which are atomic operations at a certain level of abstraction, i.e., dividing them into smaller operations is impossible. An operation should be understood as an instruction or function defined in a programming language. Index i indicates the number of the thread in which the operation is performed, and index j is the ordinal number of operations working within the same thread,
• Q P = { q s | s = 1 … κ } , q s = ( w s , x s ) , ( κ , ∈ N + ) – a set of locks available in the program, defined as a pair (mutex variable name ( w s ) , a type of lock ( x s ) ), where type is understood as one from the set value (PMN, PME, PMR, PMD),
• F P = { f n | n = 1 … ι } i F ⊆ ( O P × O P ) ∪ ( O P × R P ) ∪ ( R P × O P ) ∪ ( O P × Q P ) ∪ ( Q P × O P ) , ( ι ∈ N + ) – set of edges including: (a) transition edges – specifying the order in which the operation is performed. These edges are pairs f n = ( o i , j , o i , k ) , where the elements describe two successive operations o i , j ∈ O P , (b) usage edges – indicating resources that change during the operation. These edges are pairs f n = ( o i , j , r c ) , in which one element is operation o i , j ∈ O P , and the other is resource r c ∈ R P , (c) dependency edges – indicating operations depending on the current value of one of the resources. These edges are pairs f n = ( r c , o i , j ) , in which one element is the resource r c ∈ R P , and the other is the operation o i , j ∈ O P , (d) locking edges – indicating the operation applying the selected lock. These edges are pair f n = ( q s , o i , j ) , in which one element is the lock, and the other is the locking operation, (e) unlocking edge – indicating the operation releasing the selected lock. These edges are pairs f n = ( o i , j , q s ) , in which one element is the unlocking operation, and the other is the released lock.
• V P = Q P ∪ O P ∪ R P should be understood as a set of vertices consisting of P , application operations, P application locks, and that application’s shared resources. i s G P is understood here as a subgraph of G P graph, which is built as a result of removing:
• all vertices of O P and their associated edges excluding t i thread operation,
• all vertices of Q P set and the associated edges, excluding q s vertex,
• all vertices of R P set and their associated edges, excluding the edges between t i thread operations and the resources they use,
• transition edges ( o i , j , o i , k ) for o i , j vertex, when there is an unlocking edge for this vertex ( o i , j , q s ) .

4. Problem Definition

5. deadlock.

• Mutual exclusion: At least one resource must be non-shareable; that is, only one process can use this resource at a time. If another process requests access to the resource, it must be delayed until the resource is released.
• Hold and wait: There must be a process that has been allocated at least one resource, and that is awaiting the allocation of an additional resource that is being held by another process.
• No preemption: Resources are not subject to preemption, which means that a resource can only be released on the initiative of the holding process after the process has ended.
• Circular wait: There must be set P 0 , P 1 , … , P n of waiting processes, such that P 0 is waiting for the resource held by P 1 . P 1 is waiting for the resource held by P 2 , … , P n − 1 is waiting for the resource held by P n , and P n waiting for the resource held by P 0 process.
• mutually exclusive lock pairs (application implementing S1 scenario, let it be called DL0),
• missing the unlocking operation, e.g., as a result of a control instruction (application implementing the S2 scenario, let it be called DL1),
• retrying the lock as a result of: (a) loop operation (application implementing the S3 scenario, let it be called DL2), (b) recursive function call (application implementing the S4 scenario, let it be called DL3).

5.1. Gadara Project

5.2. dl0 application model.

DL1 Application Model

5.3. dl2 application model, 5.4. dl3 application model.

6. Sufficient Condition

• there is a pair of threads setting the same pair of locks, with the order in which these locks are set is different in both threads (Lemma 1),
• in the operation graph involving t i thread, there exists a path that starts with q s and is not a cycle (Lemma 2),
• the thread calls the recursive function, in which the PMR type lock represented by the trapezium is not used (Lemma 3).

7. Using the Source Code Model of the Multithreaded Application in Practice

7.1. leading example.

• day of the month,
• day of week,

7.2. Deadlock Detection Using Petri Nets

7.3. deadlock phenomenon detection using a multi-thread application source code model, 7.4. implementation of the method, 7.5. experiment assumptions.

• Processor: AMD Ryzen 5 1500X, 3.5 GHz,
• RAM: Corsair Vengeance LPX, DDR3, 32GB, 3000MHz, CL15,
• Hard Drive: SSD Intenso 128GB SATA3, read speed 520 MB/s.

7.6. Results

8. competitive method, 9. conclusions, author contributions, conflicts of interest, abbreviations.

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Share and Cite

Giebas, D.; Wojszczyk, R. Deadlocks Detection in Multithreaded Applications Based on Source Code Analysis. Appl. Sci. 2020 , 10 , 532. https://doi.org/10.3390/app10020532

Giebas D, Wojszczyk R. Deadlocks Detection in Multithreaded Applications Based on Source Code Analysis. Applied Sciences . 2020; 10(2):532. https://doi.org/10.3390/app10020532

Giebas, Damian, and Rafał Wojszczyk. 2020. "Deadlocks Detection in Multithreaded Applications Based on Source Code Analysis" Applied Sciences 10, no. 2: 532. https://doi.org/10.3390/app10020532

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Various Methods for Solving Deadlock Problems in Operating Systems: A Review

Related Papers

Zakaria Zubi

This paper presents a system proposal for preventing, detecting and avoiding deadlocks (PDADL), the system applies some common methods to prevent, detect and avoid deadlock on a local operating system. Moreover, the system simulates all the process and resources on a real operating system. The resources and processes can be detected dynamically from different operations running by real application programs through the operating system. We use Matrix-based algorithm for detecting the deadlock, and Banker's algorithm as well. In addition we made some modifications on the use of avoiding deadlocks in term of, eliminating the circular wait condition which is currently used for preventing deadlocks. We implement an application program named as PDADL to simulate real processes and resources from running operations in a local operating system automatically.

International Journal of Engineering Research and Technology (IJERT)

IJERT Journal

https://www.ijert.org/an-overview-on-deadlock-resolution-techniques https://www.ijert.org/research/an-overview-on-deadlock-resolution-techniques-IJERTCONV7IS12016.pdf A deadlock occurs when there is a set of processes waiting for resource held by other processes in the same set. The processes in deadlock wait indefinitely for the resources and never terminate their executions and the resources they hold are not available to any other process. The occurrence of deadlocks should be controlled effectively by their detection and resolution, but may sometimes lead to a serious system failure. After implying a detection algorithm the deadlock is resolved by a deadlock resolution algorithm whose primary step is to either select the victim then to abort the victim. This step resolves deadlock easily. This paper describes deadlock detection using wait for graph and some deadlock resolution algorithms which resolves the deadlock by selecting victims using different criteria

Prof. Surjeet Dalal

A deadlock occurs when there is a set of processes waiting for resource held by other processes in the same set. The processes in deadlock wait indefinitely for the resources and never terminate their executions and the resources they hold are not available to any other process. The occurrence of deadlocks should be controlled effectively by their detection and resolution, but may sometimes lead to a serious system failure. After implying a detection algorithm the deadlock is resolved by a deadlock resolution algorithm whose primary step is to either select the victim then to abort the victim. This step resolves deadlock easily. This paper describes deadlock detection using wait for graph and some deadlock resolution algorithms which resolves the deadlock by selecting victims using different criteria.

Ijca Proceedings on International Conference in Distributed Computing and Internet Technology 2013

Manisha Mohanty

Distributed systems deadlock is similar to single-processor system deadlock, but is worse. It is harder to avoid, prevent or detect and is harder to cure, when it is tracked down because all the relevant information is scattered over many machines. In some systems, such as distributed database systems, it can be extremely serious, so it is important to understand how it differs from ordinary deadlock and what can be done about it. Two important deadlock prevention algorithms in distributed systems are wait-die and wound-wait. Their problem is that they just attend to the time stamp of processes, but not priority of them. In a real operating system, attending to priority of processes is very important. The proposed improved algorithms are attending to both priority and time stamp of processes.

Craig Blewett

Expert systems apply Artificial Intelligence (AI) techniques to an application area, aiming (usually) to mimic the behaviour of a human expert. However, there are some AI techniques which can be used to improve the internal performance of an existing application, not necessarily currently performed by a human. In this paper, we present further research and results of EAGLE (External Advisor for Granting Locks Expertly), an expert system advisor for the lock manager in a database system. By matching lock event sequences received from the lock manager against stored scripted deadlock sequences, EAGLE is able to identify unfolding deadlock sequences. By using this Dynamic Deadlock Avoidance (DDA) approach, EAGLE is able to avoid deadlocks before they occur. Currently, no ideal solution exists to the deadlock problem. Solutions vary in terms of the number of waits for access to resources and the number of deadlock occurrences. By utilising AI techniques, DDA offers a new way of treating the deadlock problem. In this paper we describe the design of EAGLE and present the results, in terms of the number of waits and number of deadlock occurrences, occurring with DDA compared with Deadlock Detection and Resolution

Junaid Malik

Fernando Tricas

When a set of processes must share a set of common resources, deadlock problems can arise. To face them, three approaches are usually applied: deadlock detection and recovery, deadlock prevention or deadlock avoidance. In this paper we present one prevention and two avoidance deadlock algorithms for a class of models that appear in manufacturing systems. We use Petri nets as the tool for both, modelling and controlling the system. The prevention algorithm is based on an intensive use of the structure of the Petri net model. The avoidance algorithms correspond to improvements to the well-known Banker's algorithm introduced by Dijkstra in the framework of Operating Systems.

IEEE Access

Oussama Karoui

Deadlock is an undesired situation in multithreaded software since it can lead to the stoppage of software. This paper studies the problem of deadlock control of multithreaded software based on Gadara nets, which are well studied for modelling concurrent programs. In particular, an iterative deadlock prevention policy based on siphons is proposed for a class of ordinary Gadara nets where the initial marking of each idle place is one. At each iteration, we compute emptiable siphons containing the smallest number of resource places. Then, bad markings are computed based on these siphons. On the basis of the bad markings, a constraint is constructed that forbids not only bad markings that empty one of the siphons but also some other bad markings. The algorithm is carried out until no emptiable siphon exists in the net. Compared with the existing methods, the resultant net derived from the proposed method is live and maximally permissive with a simpler supervisor. Finally, two examples ...

Lecture Notes in Computer Science

Klaus Havelund

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Time based deadlock prevention for Petri nets

Challenges in application of petri nets in manufacturing systems.

Petri nets are a useful mathematical formalism for specification of manufacturing systems, supported by various analysis and verification methods. The progress made in automating control systems and the widespread use of Industry 4.0 pose a number of challenges to their application, starting from the education at university level and ending with modelling of real case studies. The paper aims to present and analyse the most relevant challenges and opportunities related to the use of Petri nets as a modelling technique of manufacturing systems. The review of the literature is primarily based on the years 2019–2020 to reflect the current state of the art. The newest approaches to deadlock prevention and recovering, but also other important analysis problems and difficulties in modelling real industrial processes are discussed. Trends for the future are also identified.

An Agent-Based Simulation Model for Deadlock Prevention in an Aisle-to-Aisle SBS/RS

Robust deadlock prevention for automated manufacturing systems with unreliable resources by using general petri nets, automatic supervisory controller for deadlock control in reconfigurable manufacturing systems with dynamic changes.

In reconfigurable manufacturing systems (RMSs), the architecture of a system can be modified during its operation. This reconfiguration can be caused by many motivations: processing rework and failures, adding new products, adding new machines, etc. In RMSs, sharing of resources may lead to deadlocks, and some operations can therefore remain incomplete. The objective of this article is to develop a novel two-step solution for quick and accurate reconfiguration of supervisory controllers for deadlock control in RMSs with dynamic changes. In the first step, the net rewriting system (NRS) is used to design a reconfigurable Petri net model under dynamic configurations. The obtained model guarantees boundedness behavioral property but may lose the other properties of a Petri net model (i.e., liveness and reversibility). The second step develops an automatic deadlock prevention policy for the reconfigurable Petri net using the siphon control method based on a place invariant to solve the deadlock problem with dynamic structure changes in RMSs and achieve liveness and reversibility behavioral properties for the system. The proposed approach is tested using examples in the literature and the results highlight the ability of the automatic deadlock prevention policy to adapt to RMSs configuration changes.

One Computational Innovation Transition-Based Recovery Policy for Flexible Manufacturing Systems Using Petri nets

In the third and fourth industrial revolutions, smart or artificial intelligence flexible manufacturing systems (FMS) seem to be the key machine equipment for capacity of factory production. However, deadlocks could hence appear due to resources competition between robots. Therefore, how to prevent deadlocks of FMS occurring is a very important and hot issue. Based on Petri nets (PN) theory, in existing literature almost all research adopts control places as their deadlock prevention mean. However, under this strategy the real optimal reachable markings are not achieved even if they claimed that their control policy is maximally permissive. Accordingly, in this paper, the author propose one novel transition-based control policy to solve the deadlock problem of FMS. The proposed control policy could also be viewed as deadlock recovery since it can recover all initial deadlock and quasi-deadlock markings. Furthermore, control transitions can be calculated and obtained once the proposed three-dimension matrix, called generating and comparing aiding matrix (GCAM) in this paper, is built. Finally, an iteration method is used until all deadlock markings become live ones. Experimental results reveal that our control policy seems still the best one among all existing methods in the literature regardless of whether these methods belong to places or transitions based.

Voting–Priority-Based Deadlock Prevention in Multi-server Multi-CS Distributed Systems

Collision-free trajectory planning with deadlock prevention: an adaptive virtual target approach, a deadlock prevention policy for a class of multithreaded software, deadlock prevention controller for automated manufacturing systems modeled by s⁴pr, export citation format, share document.

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A novel resource management technique for deadlock-free systems

Madhavi devi botlagunta.

1 Department of CSE, JNTU Kakinada, Hyderabad, India

Smriti Agrawal

2 Department of IT, ChaitanyaBharathi Institute of Technology, Hyderabad, India

R. Rajeswara Rao

3 Department of CSE, JNTUK UCEV, JNTU Kakinada, Vizianagaram, Andhra Pradesh India

Deadlock in a shared resource system is a well-known problem. It has been extensively studied and recently a new class of resource reservation technique is researched upon for deadlock free resource management. This class of technique reserves a portion of the resources. The unreserved resources are freely allocated to any process demanding it. When the unreserved resources are not sufficient for a process demand the reserve pool resources are used such that the process completes and releases all the resources it is holding. This paper presents a new resource reservation technique resource driven DFRR. This technique estimates the optimal number of resources needed for a deadlock free resource reservation policy. The correctness is proved in the form of theorem 1. The theorem 2, suggests the resource reservation with minimal resources. The overhead of the resource pool estimation is O n and that of resource management is O m which is optimal for any deadlock handling technique. The effectiveness of the proposed technique is shown in the form of examples and simulation results.

Introduction

Computing systems such as real-time [ 1 , 2 ], IoT [ 3 , 4 ], distributed, parallel, cluster, cloud computing systems, share resources for their effective utilization. The computing systems using shared resources, sometimes enter into a Deadlock, after which they are unable to execute further. Deadlocks adversely affect the system performance sometimes making it irresponsive so they are highly undesirable. Deadlock has been a big concern in both computing and non-computing shared resource systems and has been extensively studied for decades. Deadlocks will not always occur but as suggested by Coffman [ 5 ] it occurs if certain necessary conditions hold. These conditions are Mutual exclusion, Hold and wait, No pre-emption, and Circular wait condition. Thus, the first set of the Deadlock prevention (DP) resource management solution for a deadlock problem lies around these conditions. They suggest ensuring that one of the necessary conditions does not hold. The second set of Deadlock avoidance (DA), is a look forward technique to avoid deadlock in the future. The next set of solutions is event based where the system does not do any resource management rather waits for a deadlock event. The system periodically monitors for a deadlock occurrence and performs recovery action in case a deadlock is detected. Recently, a new class of techniques called Resource Reservation Techniques (RR) is also used for deadlock handling. These techniques are neither proactive nor reactive in the absolute sense. They reserve a set of resources and blindly allocate the remaining to processes for successful execution and also reduce the overhead usually caused by all other deadlock avoidance algorithms [ 6 – 9 ].

The main objective of this paper is to find optimal number of resources needed by processes to complete the execution without deadlocks in a system and also estimates how many minimal number resources of each type are sufficient. The correctness of the proposed technique can be proved in form of theorems and with the help of example and simulation results.

The rest of the paper is organized as follows: Sect.  2 , provides a further look at the existing literature. Section  3 presents the proposed Resource driven-Deadlock-free technique and its effectiveness is explained with the help of example along with comparisons of other existing techniques. Section  4 illustrates experimental results and analysis. Finally, the paper concludes with Sect.  5 and Sect.  6 gives the future scope.

Related work

Resource allocation is a critical issue in shared or concurrent systems where resources are shared to avoid deadlocks. Authors [ 10 ] introduced a new metric Mean Normalized Blocking Time to compare locking mechanisms and also provide two different semaphore models for existing real-time systems in the automotive power environment. But these locking mechanisms with significant processing overhead reduce the system performance especially for multi core processing systems where processes execute on different cores in queues waiting to acquire a lock. So this implementation of more than one lock leads the risk of deadlock. The best solution is to eliminate locks. Removing the locks is significant overhead and propose performance based lock-free algorithms [ 11 ] in multi core systems which reduces the possibility of concurrency defects and risk of deadlock. They present a multi core communication API which enhances lock-free messaging and data exchange latency between processes. Authors [ 8 ] implemented resource request algorithm to avoid deadlocks with the help of simulating software. This algorithm grants requesting resources to processes for execution and analyze the state whether in safe or unsafe after every possible situation. But they fail to provide significant improvement in system performance and also deadlock-free. Authors [ 12 ] proposed a technique which is a combination of deadlock prevention and dead- lock avoidance to detect a feasible resources and to reduce the false- positive situations by applying the Banker's algorithm. False- positive situations means it is a request, it may not actually lead to a deadlock, but still be rejected due to a failed deadlock-free test. Authors [ 13 ] proposed a new scheduling method to order products in supply chain system. Deadlocks may arise while managing multiple supply chain flows simultaneously. To prevent capital chain ruptures and increase the suppliers money flow by adopting a famous deadlock avoidance Banker's algorithm and for this method correctness SPIN tool [ 14 ] is used. Youming Li [ 7 , 15 , 16 ] proposed an improved method over traditional Dijkstra's algorithm [ 17 ] in an optimal way without losing the simplicity of the data structures and also a graph-free with the cost of linear dependence on the number of the processes, with fixed number of resources and when the units of requests for resources are bounded by constants. But this is not practically possible with resource requests are constant. Begum et al. [ 18 ] proposed a safety detection algorithm over bankers algorithm [ 17 ] using linked list data structure to store resource requests and applied radix sort for comparisons to find safety sequence with the cost of linear dependence on number of the processes and number of resources. Agrawal.et al. [ 3 ] proposed deadlock free resource reservation technique which is fairly allocating resources to all processes for their successful completion. But this has not give details of how to estimate resources sufficient for deadlock free system.

Another category of resource reservation policies which are improved over traditional deadlock avoidance algorithms by reserving some number of resources proposed by authors [ 19 – 21 ]. In this approach also considering maximum resource requirement known in advance is a major drawback. To overcome this drawback authors [ 22 , 23 ] propose budget concept which is dynamically adjusts and reserve the resources for reducing the safety sequence calls overhead in traditional avoidance algorithms.

The Resource Reservation (RR) Techniques suggest to reserve some resources that can be used to avoid the deadlock. Botlagunta et al. [ 20 ] first introduced this idea and suggested to reserve resources based on a threshold. Agrawal et al. [ 19 ] suggested to use the total need of the processes to reserve the resources. The process with minimum worst case execution time reserved the resources as suggested in [ 21 ]. Kumar et al. [ 24 ], extended the technique suggested in [ 21 ] to reserve the resources based on the remaining resource need. Botlagunta et al. [ 22 , 23 ] extended the RR techniques to dynamically allocate a budget of resources to each incoming process and perform resource reservation as per the technique suggested in [ 19 , 20 ]. These techniques are discussed in detail in the subsequent section. All the deadlock avoidance techniques have high computation time as they must perform some test before each allocation to avoid deadlock. The Resource Reservation (RR) techniques eliminated this test for deadlock avoidance and thus, reduce the turnaround time of the processes.

Both DA and RR techniques presume that the system resource requirement is known in advance. The DA techniques perform some kind of test for ensuring that the deadlock will not occur in the future. However, the Resource Reservation techniques do not perform any test rather use the knowledge of the resource requirement for estimating the portion of resources that must be reserved to avoid deadlock. The resource reserved by different RR Techniques existing so far is not sufficient for completely avoiding the deadlock. The present work extends the idea of the (RR) techniques to use the knowledge of the resource requirement by the processes for estimating the reserve pool strength. The proposed technique ensures that all the processes have the opportunity to complete with the reserved resources.

Proposed resource driven Deadlock free resource reservation (DFRR)

This work is an extension of the Deadlock-free resource reservation techniques (DFRR) [ 3 ]. The DFRR technique is free from deadlocks and its effectiveness is proved in the form of theorems. However, DFRR does not suggests how to estimate the resources that would be sufficient for a deadlock-free system. This work reexamines the DFRR technique from the systems point of view and proposes resource driven Deadlock free resource reservation (DFRR) technique. It considers a system that has a finite set of resources and manages its resources for a process set ensuring deadlock-free implementation. The system model used in this work is the same as used in [ 3 ]. The system consisting of R 1 , R 2 , R 3 ⋯ R m resources with α 1 , α 2 , α 3 ⋯ α m instances of each type. These resources are portioned into Reserve[j] and Available[j] pools. This system executes n independent processes P 1 , P 2 , P 3 ⋯ P n with their maximum resource requirement represented as Max[i][j] .The resources allocated to a process are represented as Allocation[i][j], further resources needed are estimated as Need[i][j] and requested are Request[i][j].

The theorem 1, estimates the optimal resources used for a deadlock-free system. The DFRR further, investigates the systems with lower resources and suggests theorem 2 for a deadlock-free management. The proposed resource driven DFRR works on the same principle as DFRR but it examines the resources required by the processes and that available in the system. It suggested to reserve some resources in the reservation pool. The remaining resources are made available in the available pool. Whenever, a process requests for a set of resources, available pool resources are granted. In case the request cannot be granted only from the available pool then the reserved pool resources are also used such that the maximum resources this process can ever want are granted, giving it the chance to complete.

The theorem 1 is presented below to estimate the optimal number of resources needed for a deadlock-free system.

A system with α 1 , α 2 , α 3 ⋯ α m instances of resource types R 1 , R 2 , R 3 ⋯ R m can schedule a set of independent processes P 1 , P 2 , P 3 ⋯ P n with resource requirement as Max i j , in deadlock-free manner if ∑ i = 1 n Max i j - η j - 1 ∗ Reserve j ≤ α j where

i. η j is the number of processes requesting for the resource R j i.e., c o u n t M a x i j ≠ 0 ∀ i = 1 , 2 ⋯ n

ii. R e s e r v e j = M a x i j ∀ i = 1 , 2 … n , 0

iii. A process P i can acquire either

a. M a x i j - R e s e r v e j resources from the available pool,

b. M a x i j ∀ R j from available and reserve pool put together such that the available pool is consumed first. That is a process must acquire all the resource it might need.

iv. A process P i on completion relinquishes all the resources, M a x i j ∀ R j , that are returned to the reserve and available pools as per condition i.

By definition:

In worst case as per the condition iii. a. the resources any process can acquire is as per Eq. ( 2 ).

Thus, each process needs R e s e r v e j resources to complete it’s execution.

Total number of resources allocated to all the processes is ∑ i = 1 n A l l o c a t i o n i j .

Substituting Eq. ( 1 ) and ( 2 ) in ( 3 )

Thus, ∑ i = 1 n M a x i j - η j - 1 ∗ R e s e r v e j ≤ α j ∀ j = 1 , 2 ⋯ m resources are sufficient for deadlock-free execution. Hence Proved. □

A system with α j ≥ ∑ i = 1 n M a x i j ∀ j = 1 , 2 ⋯ m is a generic deadlock-free system because it has more resources then it can ever consume with all the processes holding their complete set. However, a system with α j = ∑ i = 1 n M a x i j - η j - 1 ∗ R e s e r v e j has optimal number of resources. This is actually under-utilization of resources. This value will always be lower than ∑ i = 1 n M a x i j ∀ j = 1 , 2 ⋯ m , indicating that the DFRR can achieve deadlock-free system with lower number of resources. This estimated α j = ∑ i = 1 n M a x i j - η j - 1 ∗ R e s e r v e j is referred of α opt j . The overhead is only O n for estimating the reserve pool initially. This technique as with all other reservation technique does not perform any kind of testing before allocating the resources and hence, has minimal overhead.

The following example illustrates the effectiveness of the proposed technique and compares it with other existing reservation techniques.

Example: consider a set of processes P 1 , P 2 , P 3 , P 4 , P 5 with the resource requirement as suggested in Table ​ Table1 1 The chronological sequence of resource requests as shown in the Table ​ Table2 2 .

Snapshot of the system at the start time t 0

Sequence of requests

NG * Not Granted (moved to pending queue), GRP ** Grants from Reserve Pool

The resource management by all the existing techniques is examined in the following subsections

Data structures after request Req 16 of (0, 1, 0, 0) is granted to P 1

Data structures before Req 16 of (0, 1, 0, 0) is granted to P 1

Safety sequence <  P 1 , P 2 , P 3 , P 4 , P 5 >

Data structures after Req 17 of (0, 0, 0, 1) is granted to P 5

• Worst-case execution time based resource reservation (ETRR) Technique [ 7 ] : The shortest execution time process is selected for the resource reservation. In the example given in Table ​ Table1, 1 , the shortest process is P 1 thus, (5, 6, 3, 4) resources are reserved. The requests Req 1 t o Req 9 are granted, however request Req 10 for (1, 1, 0, 0) by process P 4 , cannot be satisfied from the available pool. The process is thus, assigned resources from the available and reserve pool put together. It then completes and hand over the resources it was holding. This technique works well when the resource requirement of the shortest process is high. However, if the shortest job was process P 2 then this system would have ended in a deadlock.
• Proposed DFRR: The proposed resource driven DFRR technique considers the nascent system in the Table ​ Table1 1 with no initial allocation. The reserve pool is estimated using equation R e s e r v e j = M a x i j ∀ i = 1 , 2 … n , 0 as (2, 3, 3, 3) and the remaining (10, 6, 4, 4) resources are in the available pool. The requests Req 1 t o Req 15 for the resources are granted and the system state can be seen the Table ​ Table4.It 4 .It may be noted that the safety sequence is never calculated and reserve pool is also estimated only once. When the request Req 16 is made by P 1 the available pool is empty so the resources from the reserve pool are allocated to it to accelerate its completion lowering its turnaround time. Elimination of the SS estimation also lowers the wait time and hence, the turnaround time of all the processes. The process P 1 on its completion releases all the resources it is holding and system continues its operation.

Another interesting question to ask is what happens if number of resources in the system are lower than α opt j that is α j < α opt j ? If the resources can be allocated as per the theorem 1, the system may end up in a deadlock. The resource driven DFRR technique suggests to modify the resource allocation policy whose correctness is proved in the theorem 2.

A system with α 1 , α 2 , α 3 ⋯ α m instances of resource types R 1 , R 2 , R 3 ⋯ R m can schedule a set of independent processes P 1 , P 2 , P 3 ⋯ P n with resource requirement as Max i j , in deadlock-free manner if α j ≥ ⌈ Max i j ⌉ where

a. M a x i j - R e s e r v e j - α o p t j - α j η j - 1 , 0 where α opt = ∑ i = 1 n M a x i j - η j - 1 ∗ R e s e r v e j resources from the available pool such that α j ≤ α opt j ,

Proving by contradiction that total resources allocated are greater than available in the system:

Substituting in (4): A v a i l a b l e j = α j - R e s e r v e j , ∀ R j

Substituting in (5): A l l o c a t i o n i j  = M a x i j - R e s e r v e j - α opt j - α j n - 1

as per the equation iii. a. from theorem 2.

In worst case η j = n implying that the resource is being used by all the processes in the system.

Substituting as suggested in the theorem 2 iii. a. ; α opt = ∑ i = 1 n M a x i j - η j - 1 ∗ R e s e r v e j

In worst case η j = n implying that the resource is being used by all the processes in the system. Therefore,

Thus, ⇒ α opt j - n ∗ α opt j - α j n - 1 > α j , ∀ R j

However, α j < α opt j , hence contradiction. Therefore, ∑ i = 1 n A l l o c a t i o n i j ≤ A v a i l a b l e j , ∀ R j , implying that the system remains feasible. Hence Proved. □

In the above example if the resources are reduced from α opt = 12 , 9 , 7 , 7 to α = ( 10 , 8 , 6 , 6 ) . The total allocation possible is ∑ i = 1 n A l l o c a t i o n i [ ] = ( 6 , 4 , 2 , 1 ) , as per condition iii. a. from theorem 2, therefore the remaining resources are 10 , 8 , 6 , 6 - 6 , 4 , 2 , 1 = ( 4 , , 4 , 4 , 5 ) , sufficient for any process to complete hence, this system remains deadlock free with lower resources also. The following section present the simulation results.

Simulations results

This section presents the results of the simulations performed on the synthesized process sets generated. The performance of the proposed DFRR is compared with various existing techniques.

Resource instances Vs. Avg. turnaround time:

Resource instances Vs Avg. turnaround time

Resource bound Vs Avg.turnaround time

This paper presented a new resource reservation technique for resource management in shared resource systems. The proposed DFRR technique is a deadlock-free resource management technique. Unlike other resource reservation techniques, DFRR suggests resource management based on the resources in the system. It suggests a deadlock free resource management for minimal resource system. It also suggests the optimal number of resources needed for a process set to efficiently execute on a system. The correctness of the technique is proved in the form of two theorems. The theorem 1, answers, given a process set how many resources will be sufficient for its efficient execution. While theorem 2, suggest resource management based on the resources available in the system to the demanding process set. Its effectiveness is demonstrated by an example and simulation results.

The DFRR belongs to resource reservation class of deadlock handling techniques. This class of techniques eliminate the excessive overhead incurred by the Deadlock Prevention and Avoidance techniques as well as the uncertainty of deadlock occurrence in the deadlock detection and recovery techniques. In other words, the proposed technique achieved deadlock freeness as any deadlock avoidance technique with the overhead of a deadlock detection and recovery technique, which is optimal. The overhead in these technique is only for the reservation pool estimation. The proposed technique estimates the reservation pool by finding a minimum in an array of ‘n’ where ‘n’ is the number of processes in the system. Hence, the overhead for reservation pool estimation is O ( n ) .The simulation results indicate that the turnaround time of the proposed DFRR is approximately 18% better than the existing Banker’s algorithm. Thus, the proposed technique is a deadlock-free technique with optimal overhead.

Future work

This work considers resource management based on the resources available in the system to the demanding process set. This work can be applied to study resource management during hospitalization due to the present pandemic of Covid-19.

Contributor Information

Madhavi Devi Botlagunta, Email: [email protected] .

Smriti Agrawal, Email: [email protected] .

R. Rajeswara Rao, Email: [email protected] .

Middle East Crisis U.N. Security Council Passes U.S.-Backed Cease-Fire Resolution

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• Palestinians searching through rubble on Sunday after an Israeli raid to release hostages in the Nuseirat area. Eyad Baba/Agence France-Presse — Getty Images
• Secretary of State Antony J. Blinken arriving in Cairo at the start of another regional tour. Pool photo by Amr Nabil
• Mourning over the bodies of Palestinians killed in an Israeli airstrike, outside a hospital in Deir al Balah, in central Gaza. Jehad Alshrafi/Associated Press
• Smoke rising over Al Fara'a, in the occupied West Bank, following an Israeli military raid. Majdi Mohammed/Associated Press
• A screen in Tel Aviv displaying a picture of Andrey Kozlov, one of four hostages rescued by Israeli forces on Saturday, Marko Djurica/Reuters
• Posters in Tel Aviv of Israeli hostages being held in Gaza. Marko Djurica/Reuters
• A woman in her damaged home in the Nuseirat area of central Gaza on Sunday. Abed Khaled/Reuters

Fourteen of the 15 members voted in favor, with Russia abstaining.

United nations security council backs gaza cease-fire resolution, fourteen of the 15 members on the u.n. security council, with russia abstaining, voted in favor of adopting a proposal calling for a permanent cease-fire in gaza. neither israel nor hamas has formally embraced the plan..

“14 votes in favor, zero votes against, one abstention. The draft resolution has been adopted as resolution 2735.” “Colleagues, the cease-fire deal would pave the way toward an enduring cessation of hostilities and a better future for all. As President Biden acknowledged just the other day, the Palestinian people have endured sheer hell in this war started by Hamas. There’s an opportunity to chart a different course.”

The U.N. Security Council on Monday adopted a U.S.-backed cease-fire plan for the Gaza Strip after Russia opted not to block it, adding extra heft to a growing international push for an end to the fighting.

Fourteen of the 15 Council members voted in favor, with Russia — which has veto power — abstaining.

In passing the resolution, the Council delivered a diplomatic victory to Washington, which had vetoed three previous cease-fire resolutions before the Council.

“The only way to end this cycle of violence and build a durable peace is through a political settlement,” said Linda Thomas-Greenfield, the U.S. ambassador to the United Nations.

Ms. Thomas-Greenfield said that the United States would work to make sure that Israel agreed to the deal and that Qatar and Egypt would work to bring Hamas to the negotiating table.

“Colleagues, today we voted for peace,” she said.

The resolution laid out a three-phase plan that begins with an immediate cease-fire, the release of all hostages in exchange for Palestinians being held in Israeli prisons, the return of displaced Gazans to their homes and the full withdrawal of Israeli forces from Gaza.

The second phase calls for a permanent cease-fire with the agreement of both parties, and the third phase would consist of a multiyear reconstruction plan for Gaza and return of the remains of deceased hostages.

“The proposal says if the negotiations take longer than six weeks for phase one, the cease-fire will still continue as long as negotiations continue,” the resolution said. It also rejected “any attempt at demographic or territorial change in the Gaza Strip, including any actions that reduce the territory of Gaza.”

Israel’s representative to the U.N., Reut Shapir Ben-Naftaly, did not say that Israel had accepted the terms, but said her country’s goals in the war had not changed and that it would use military operations to free hostages as it did just two days ago.

“We will continue until all of the hostages are returned and Hamas’s military capabilities are dismantled,” Ms. Shapir Ben-Naftaly told the Council. She said if Hamas leaders freed all hostages and turned themselves in, “not one shot would be fired.”

In a statement, Hamas said it “welcomes what is included in the Security Council resolution that affirmed the permanent cease-fire in Gaza, the complete withdrawal, the prisoners’ exchange, the reconstruction, the return of the displaced to their areas of residence, the rejection of any demographic change or reduction in the area of the Gaza Strip, and the delivery of needed aid to our people in the Strip.”

The Russian ambassador to the United Nations, Vasily Nebenzya, said that the Council remained in the dark about the details of the U.S.’s agreement with Israel and had “essentially voted for a cat in the bag.”

But Mr. Nebenzya said Russia had decided to abstain because the resolution had widespread support by Arab countries.

The American Mission to the United Nations began drafting the resolution and negotiating over it in the days after President Biden announced on May 31 that Israel had put forth a cease-fire deal. The resolution follows the same framework that Mr. Biden set out, according to Nate Evans, the spokesman for the U.S. mission.

“This deal is how we will achieve the cease-fire with the release of hostages,” said Mr. Evans. “Israel has accepted the deal. Now it’s time for Hamas to do it.”

Israeli officials have not publicly endorsed the cease-fire plan, and they have not said whether they would abide by the deal if Hamas accepts it. A day after Mr. Biden’s announcement, the office of Prime Minister Benjamin Netanyahu issued a statement that appeared to undercut the proposal, calling a permanent cease-fire a “nonstarter.”

Diplomats said that during negotiations, the United States asked Security Council members to take its word that Israel was on board, and refused to incorporate clear language in the text that Israel accept the deal.

The draft resolution states only that Israel has accepted the U.S. proposal, but it “calls” for Hamas to accept the deal. Russia and China and Algeria, the only Arab member of the Security Council, had said in back-channel negotiations that the text appeared too lopsided in favor of Israel.

Ever since the war started eight months ago, the Security Council has been in a deadlock over finding a way to end the conflict and fulfill its mandate to uphold international peace and stability.

China, which vetoed a cease-fire resolution put forth by the United States in March because it said the proposal did not go far enough, said that it had voted in favor of this one because it wants to see the fighting end and the hostages released.

Its ambassador to the U.N., Fu Cong, said China supported it even though the resolution was “ambiguous in many aspects.”

“We still have valid concerns on whether the parties concerned will accept the terms of the cease-fire and whether the arrangement can be carried out smoothly,” he said.

The United States has vetoed three resolutions calling for a cease-fire. In March, after the U.S. abstained, the Council passed a resolution calling for a humanitarian cease-fire and more desperately needed aid to be allowed into Gaza during Ramadan.

Neither of the parties has abided by that resolution.

— Farnaz Fassihi

Blinken urges Mideast leaders to press Hamas over a cease-fire.

Secretary of State Antony J. Blinken met with Israeli Prime Minister Benjamin Netanyahu on Monday in Jerusalem, as the United States sought to put pressure on Hamas and Israel to agree to a cease-fire in Gaza.

Mr. Blinken reiterated that the United States and other world leaders will stand behind the proposal outlined by President Biden that would lead to an immediate cease-fire in Gaza, the release of all hostages, and a sustained increase in humanitarian assistance for Gaza.

It was the second stop of Mr. Blinken’s three-day Mideast tour; he and the prime minister met late in the evening and Mr. Blinken was expected to meet later with Defense Minister Yoav Gallant in Tel Aviv, the State Department said.

During the meeting, Mr. Blinken underscored the United States’ ironclad commitment to Israel’s security, including ensuring that Oct. 7 can never be repeated. The proposal, he added, would unlock the possibility of calm along Israel’s northern border and further integration with countries in the region.

Mr. Blinken also updated the prime minister on diplomatic efforts to plan for the post-conflict period, emphasizing the importance of those efforts to providing long-term peace, security, and stability to Israelis and Palestinians alike. Mr. Blinken also emphasized the importance of preventing the conflict from spreading.

Earlier on Monday, Mr. Blinken held talks in Cairo with President Abdel Fattah el-Sisi, whose government has helped mediate negotiations between Israel and Hamas over a proposed cease-fire deal offered by Israel and backed by the United States.

“My message to governments throughout the region is: If you want a cease-fire, press Hamas to say yes,” Mr. Blinken told reporters before departing Cairo.

But Mr. Blinken was also expected to press Israeli officials over the proposal, which President Biden has endorsed.

More than two weeks have passed since Israel presented the deal to Hamas, and even Mr. Netanyahu’s government has not formally embraced it. The Israeli prime minister, under pressure from far-right members of his government, has said publicly that the Israeli assault in Gaza should continue until Hamas’s military and governing capabilities are destroyed.

There has also been no official response to the proposal from Hamas. Some Hamas officials have suggested that they cannot agree to a limited halt to the fighting without greater assurances that Israel is prepared to negotiate an end to the war. U.S. officials say they are awaiting more definitive word from Hamas.

It was also unclear whether the Israeli raid on Saturday, which freed four hostages from Hamas captivity but killed dozens of Palestinians, might have further set back the chances that the militant group would agree to a deal.

Tensions have grown between Mr. Biden and Mr. Netanyahu over the number of Palestinian civilians killed by Israel’s military during the war in Gaza. Mr. Biden said last month that he had paused the delivery to Israel of some larger bombs to ensure that they were not used in an assault on the Gazan city of Rafah.

Mr. Blinken is visiting Israel at a time of domestic tumult , following the move by Benny Gantz, a Netanyahu rival, and his centrist National Unity party to leave the emergency wartime government in protest of Mr. Netanyahu’s handling of the war.

On his eighth trip to the region since the Oct. 7 Hamas-led attacks, Mr. Blinken also plans to visit Qatar, another Arab nation mediating between Israel and Hamas. Qatar hosts Hamas’s political leaders, though the group’s ultimate decisions are made by its leader in Gaza, Yahya Sinwar.

Mr. Blinken’s efforts come a few days after inconclusive visits to Egypt and Qatar last week by the C.IA. director, William J. Burns, and Brett McGurk, the top White House official for Middle East affairs, in pursuit of a cease-fire deal.

In Jordan, Mr. Blinken will attend a conference Tuesday on humanitarian aid for Gaza co-hosted by Jordan, Egypt and the United Nations.

— Michael Crowley

Israel’s Parliament revives a bill on drafting ultra-Orthodox men into the military.

Israel’s Parliament on Tuesday voted to revive a bill that would enable ultra-Orthodox men to be drafted into the military, a divisive issue that has become especially contentious since the war in Gaza began last October.

The vote, which passed 63-57, was a procedural step aimed at keeping the hot-button issue in the hands of legislators instead of judges, who have repeatedly determined that the exemption, dating to the founding of Israel, should not stand .

Many secular Israelis have long lamented the draft exemptions for the most religious members of society. The issue has taken new prominence since the Hamas-led attack in Israel on Oct. 7 set off a war that has prompted repeated call-ups of reserve soldiers.

The bill, which revives a proposal made in 2022, would limit the exemption for young ultra-Orthodox men enrolled in religious study, establish recruitment quotas for them and provide alternative service options, among other changes. Some critics contend, however, that the proposal would not significantly increase military service among the ultra-Orthodox, known in Hebrew as Haredim.

The bill was advanced in May by Prime Minister Benjamin Netanyahu, in an apparent effort to deter Israel’s Supreme Court from taking the lead on the matter. The justices are currently considering whether the government must immediately begin drafting the ultra-Orthodox, following the expiration of a law last year that was temporarily extended and has expired again.

The vote on Tuesday was widely seen as intended to send a signal to the court that the Knesset was addressing the issue. The court ordered the government to address it long ago, but years of legislative efforts have failed to produce meaningful change.

Some members of Mr. Netanyahu’s Likud party said that they would support the bill’s revival in order to speed up the legislative process, but they promised to demand changes before it advanced.

The Israeli attorney general, Gali Baharav-Miara, has pressed for immediate conscription of the country’s ultra-Orthodox, arguing that the government’s inability to pass new legislation did not excuse the failure to begin drafting the Haredim after the expiration of the previous exemption law.

The dispute is rooted in decisions made in the years surrounding Israel’s founding, when the country’s secular leadership promised autonomy and privileges to the ultra-Orthodox minority in exchange for their support in creating a largely secular state. Along with being exempted from the draft, the Haredim are allowed to run their own education system.

When the numbers of the Haredim were relatively small, their privileges mattered less to the Israeli mainstream. But they are Israel’s fastest-growing population, now numbering more than one million, or roughly 13 percent of the population, up from 40,000, or 5 percent, in 1948. They are expected to make up about 16 percent of the nation by 2030.

If the Supreme Court can be persuaded that Mr. Netanyahu’s government is making a serious effort to address the issue, the justices may give the Knesset time to pass a law. If not, the court may decide to order immediate action, and that could lead to a crisis for Mr. Netanyahu, whose coalition relies on the support of the ultra-Orthodox.

— Ephrat Livni

Gazans in the area where hostages were rescued plead for an end to the war.

Gazans describe deadly israeli raid in nuseirat, palestinians pleaded for an end to the war in gaza after an israeli raid to release hostages in the nuseirat area in central gaza left more than 200 people dead, according to palestinian health officials..

Yesterday, It was a horrible situation. Happened about around 10 o’clock in our local time. Began bombing everywhere and the airstrikes were everywhere. The people were running in fear, and a lot of horrible things are going on the streets. I hope, I hope that human person, human leaders will interfere to cease-fire soon. Soon because you don’t know what the miserable situation that the people live in here in Gaza.

As a neighborhood in central Gaza reeled on Monday in the aftermath of Israeli attacks that accompanied the rescue of four hostages, residents pleaded for an end to the fighting.

Dozens of people picked through the rubble of buildings in Nuseirat after part of the neighborhood was shattered during the Saturday raid. Video by Reuters showed people walking through streets full of crumbled masonry and glass, and cars that had been crushed by blocks of concrete.

Mohamed al Tahrani, a resident of the neighborhood, said that he had spent months seeking safety from the fighting. “For the millionth time, we deliver a message to the international community,” he said. “We don’t want aid. We want you to stop the war.”

Gazan health officials said that more than 200 people had been killed in the raid. The Israel military said it was aware of fewer than 100 casualties, but gave no further details. It was unclear how many of the casualties were civilians.

— Nader Ibrahim ,  Erika Solomon and Matthew Mpoke Bigg

Israel’s military says 3 recently rescued hostages were held in a home of a Hamas member.

Following the Israeli rescue of four hostages in Gaza on Saturday, Israel’s military said that three of them had been held in the home of a member of Hamas, which it said showed that the armed group was using civilian homes to shield its activity.

Israeli special forces, backed by the military, intelligence and air force, raided two buildings in a neighborhood in Nuseirat, a refugee camp in central Gaza on Saturday, rescuing Almog Meir Jan, 22; Andrey Kozlov, 27; and Shlomi Ziv, 41, from the home of Abdallah Aljamal, the military said. A fourth hostage, Noa Argamani, 26, was also freed, apparently from a nearby building.

More than 274 people were killed during the raid, according to Gaza’s health ministry. The Israeli military said that the death toll was less than 100. Neither the Israeli military nor Palestinian health officials provided a breakdown of civilians and combatants killed in the raid.

Mr. Aljamal’s death was confirmed by Gaza’s Government Media Office on Sunday, which said he had worked for the Hamas-affiliated news agency, Palestine Now.

On Sunday, the Israeli military said in a statement on the Telegram messaging app: “The hostages were held captive by Abdallah Aljamal and members of his family in their home. This is further evidence of the deliberate use of civilian homes and buildings by the Hamas terrorist organization to hold Israeli hostages captive in the Gaza Strip.”

Israel’s military has said for months that civilian casualties in Gaza are inevitable because Hamas hides its forces within the population.

However, the Israeli military appeared to be stepping back on Monday from its post a day earlier on the X platform, formerly Twitter, that implied that Mr. Aljamal was a journalist for Al Jazeera, an influential news organization based in Qatar.

In that post, the military showed what appeared to be a screenshot of a photo and brief biography of Mr. Aljamal on the news organization’s website. “No press vest can make him innocent of the crimes he has committed,” the post said, adding, “Al Jazeera: what’s this terrorist doing on your website.”

Al Jazeera refuted the accusation on Sunday, saying that “these allegations are completely unfounded” and that Mr. Aljamal had “never worked” for the network. Rather, it said, he had contributed to an op-ed in 2019. A search of Al Jazeera’s website for his byline surfaces a co-written opinion piece from January of that year collecting accounts of six Palestinians who had been held in Israeli prisons. News organizations frequently publish opinion pieces from contributors who are not on staff and with whom they have no ongoing contractual relationship.

Al Jazeera is a major source of news in the Arab world and has highlighted civilian suffering in Gaza. Prime Minister Benjamin Netanyahu has accused it of harming Israel’s security and inciting violence against its soldiers. The news organization has been under a temporary ban from operating in Israel since May 5 — an unusual step that critics denounced as anti-democratic and part of a broader crackdown on dissent over Israel’s war against Hamas in Gaza.

A 35-day ban on Al Jazeera’s operations in Israel was extended by an additional 45 days last Wednesday, after the Israeli cabinet agreed Al Jazeera’s broadcasts posed a threat to security.

On Monday, the Israeli military said it had no comment on Al Jazeera’s rebuttal, referring a Times reporter back to its Sunday Telegram post, which identified Mr. Aljamal only as a member of Hamas. However, Israel’s Ministry of Foreign Affairs continued to amplify the accusation that he was connected to Al Jazeera, reposting on Monday a report by The New York Post that cited the military’s Sunday post on X.

It was not possible to ascertain independently whether the hostages had been held in Mr. Aljamal’s home and, if so, under what circumstances.

Given that Abdallah Aljamal is a relatively common name in Gaza, it was also not possible to be certain that the person who wrote the op-ed was the same person whose home Israel’s military said was used to hold the hostages.

According to a preliminary estimate by the Committee to Protect Journalists, more than 100 journalists and media workers have been killed during Israel’s campaign in Gaza, which began on Oct. 7 when Hamas launched an attack on Israel. It calls that an unprecedented toll on Palestinian journalists.

Israeli officials have said that they believed that some of those journalists were also members of Hamas, an assertion that serves to cast doubt on the neutrality of some of the reporting conducted by Palestinian journalists. Because foreign media are barred from entering the enclave outside of special tours closely monitored by the military, Palestinian journalists have become a crucial source of information about prosecution of the war and its impact on civilians.

Aaron Boxerman contributed reporting.

— Matthew Mpoke Bigg

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