identical data structures.Only way is to add "per CPU variable". For slab, it can be expanded to look like this:650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M00/73/41/wKiom1X4iV2xRF9WAAGuLWLD-H4129.jpg "title=" Slab3.jpg "alt=" Wkiom1x4iv2xrf9waagulwld-h4129.jpg "/>If you think it's over, it's pointless.ProblemFirst, let's look at a simple question, if a separate CPU's slab cache has no objects to allocate, but the other CPU's slab cache still has a large number of idle objects, as sh
I. Overview:I received A friend's question in my blog. After phone communication, I learned the approximate situation:. the headquarters has a leased line to partner B. the partner side is not convenient to add a back-to-point route. When the Headquarters accesses the partner, PATC is implemented. now, if you want to connect the branch L2L VPN to the headquarters
After talking about this, many people will surely get confused. What we mentioned above is data structures or conceptual things. Where is the real management mechanism for dynamic pages? In other words, how do I allocate the page boxes of each node and area to processes? To clarify this idea, we must first learn an algorithm-partner system algorithm.
To assign a set of consecutive page boxes to the kernel, a robust and efficient allocation policy mus
Definition
As explained in presentation partner determination in SD can be configured for 8 activities I. e.
1. the settings of these eight projects are basically the same
2. Some views in these settings are the same, that is to say, the setting results can also be seen in other options set in one.
For example, the partner function is View: v_tpar_sd.
The Process
1. Define
One, Partner link type (Partner link Types)1. Interactive processThe interaction process between partners is divided into two typical situations:
The process calls the partner after the synchronization waits for the result to be returned. This is usually the case when a partner can return the results quickly,
The call relationship between Linux memory release functions is shown in. the result is the _ free_pages () function, the following figure shows the workflow of the function execution. the code [cpp] void _ free_pages (structpage * page ,...
The call relationship between Linux memory release functions is shown in. the result is the _ free_pages () function. the execution workflow is shown in.
The following code shows the function: [cpp] void _ free_pages (struct page * page, unsigned int order)
Hi, Buddy!
Hedgehog @ http://blog.csdn.net/littlehedgehog
Bitmap
In the Linux kernel partner algorithm, the bitmap of each order indicates all idle blocks. For example, the memory of my computer is 256 MB (now I can compare the cards on the last qq homepage ), in theory, bitmap with order 0 contains 256 MB/(4 K * 2) blocks. Why divide by two? Because a bitmap corresponds to two partner blocks, 1 indica
1, the role of the partner system:The partner system is primarily designed for efficient use of physical memory, minimizing the generation of memory fragments2, the concept of the partner system:Memory in the system is always 22 grouped, and two memory blocks in each group are called partners3, the principle of the partner
When the coal mine in the house is relocated, it is about to be moved, and the pockets are occupied. The village is built on the second floor, so bricks are moved.
The price in Beijing is too expensive. To buy a house, you can only start one piece now. You can slowly move bricks, complain less, and move more bricks.
Record what you learned every day. Repeat and repeat.
I. Partner Algorithms
1. Partner Syste
For example, BPEL4WS (4) --- what is a partner connection
In BPEL4WS, the interaction service of a business process is represented by a partner connection. Each partner connection is identified by a partner connection type, but many
The connection type of a partner can be
Assuming that the system can use 2 m characters in memory space (from 0 to 2 m addresses), the entire memory zone is an idle block with a size of 2 m at the start of operation, after running for a period of time, it is divided into several occupied blocks and idle blocks. To facilitate searching during allocation, we create all idle blocks of the same size in a subtable. Each sub-table is a double linked list. Such a linked list may contain m + 1, which organizes the m + 1 header pointer into a
one of the important things about kernel memory management is how to avoid fragmentation when you frequently request to release memory. This requires the kernel to adopt a flexible and appropriate memory allocation strategy. Typically, memory allocations generally have two situations: large objects (large contiguous space allocations), small objects (small spatial allocations). For different requirements, Linux has taken the partner system algorithm a
After talking about this, many people will surely get confused. What we mentioned above is data structures or conceptual things. Where is the real management mechanism for dynamic pages? In other words, how do I allocate the page boxes of each node and area to processes? To clarify this idea, we must first learnAlgorithm-- Partner system algorithm.
To assign a set of consecutive page boxes to the kernel, a robust and efficient allocation policy must
shown in:This is possible because the requirement for a single slab is closely related to the processes/threads that are executed on the CPU, such as if CPU0 only handles the network, it will have a large demand for data structures such as SKB, and for the final question, if we choose to assign a new page from the partner system ( or pages, depending on the size of the object and the order of the slab cache, it will cause slab to be unevenly distribu
1. PrefaceThe series of articles about memory management in this article is mainly about the memory management knowledge lecture of Chen Li June teacher.This lecture is divided into three topics on memory management: Hardware foundation of memory management, management of virtual address space, management of physical address space.This paper mainly introduces the X86 architecture as an example to introduce the partner algorithm and slab assignment2. O
Transferred from: http://blog.csdn.net/orange_os/article/details/7392986Advantages and disadvantages of the buddy algorithm:1) Although the partner memory algorithm has done quite well on the memory fragmentation issue, but in this algorithm, a very small block will often hinder a large chunk of the merger, a system, the allocation of memory blocks, the size is random, a piece of memory only a small block of memory is not released, next to the two lar
Advantages and disadvantages of the buddy algorithm:1) Although the partner memory algorithm has done quite well on the memory fragmentation issue, but in this algorithm, a very small block will often hinder a large chunk of the merger, a system, the allocation of memory blocks, the size is random, a piece of memory only a small block of memory is not released, next to the two large can not be merged.2) There is a certain waste in the algorithm, the
_
The following are the definitions of malloc and free functions:
# Include "malloc. H "
Buddy algorithm (partner algorithm)
As described in the reference algorithm, the core idea of the partner algorithm is to set the block size, usually the power of 2.
Here we have a maximum power value, called u, that is, the maximum block is as large as 2 ^ U.
There is a minimum power value called L. The minimum blo
I have introduced the principles of the partner system and the data structure of the Linux partner system. Now I want to see how the partner system allocates pages. In fact, the algorithm for page allocation in the partner system is not complex, but the generation of fragments (involving the Migration Mechanism) should
Related links:Linux partner System (1) -- Partner System Overview (2) -- Partner system initialization http://www.bkjia.com/ OS /201206/135691.html#linux System (3) -- allocate quota (4) -- release page http://www.bkjia.com/ OS /201206/134247.html linux introduces the concept of the migration type (migrate type) in the partne
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