JEFF BONWICK SLAB ALLOCATOR PDF

The slab allocator: an object-caching kernel memory allocator . Jeff Bonwick, Jonathan Adams, Magazines and Vmem: Extending the Slab. Implementation of the Slab Allocator as described in “The Slab Allocator: An Object-Caching Kernel Memory Allocator” by Jeff Bonwick. – lucastsa/ slab_allocator. This package provides a simple implementation of a Slab memory allocator (Jeff Bonwick: “The Slab Allocator: An Object-Caching Kernel Memory Allocator”).

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Not to be confused with Slab unit.

The technique is used to retain allocated memory that contains a data object of a certain type for reuse upon subsequent allocations of objects of the same type. This process eliminates the need to search for suitable memory space and greatly alleviates memory fragmentation.

A aloocator slab is exactly one page, and has a defined structure that allows bufctls to be avoided. These same primitives prove equally effective for managing stateless allocatot e.

Advanced Search Include Citations. Slab allocation is a memory management mechanism intended for the efficient memory allocation of kernel objects.

Slab allocation

It represents one memory allocation to the cache from the machine, and whose size is customarily a multiple of the page size. By using this site, you agree to the Terms of Use and Privacy Policy.

It eliminates fragmentation caused by allocations and deallocations. From Wikipedia, the free encyclopedia.

CiteSeerX — The Slab Allocator: An Object-Caching Kernel Memory Allocator

In this context, a slab is one or more contiguous pages in the memory containing pre-allocated memory chunks. Destruction of the object does not free up the memory, but only opens a slot which is put in the list of free slots by the slab allocator. It is analogous to an object poolbut only applies to memory, not other resources. Retrieved 18 November This allows the small slab’s bufctl to be bypassed.

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Slab allocation was first introduced in the Solaris 2. This paper presents a comprehensive design overview of the SunOS 5.

Slab Allocator

A slab is the amount by which a cache can grow or shrink. The last part of the page contains the ‘slab header’, which is the information needed to retain the slab. The primary motivation for slab allocation is that the initialization and destruction of kernel data objects can actually outweigh the cost of allocating memory for them. This allocator is based on a set of object-caching primitives that reduce the cost of allocating complex objects by retaining their state between uses.

The new object gets allocated from this slab, and its location becomes marked aplocator “partial”. This page was last edited on 23 Decemberat These small slabs need to be optimized further from the logical layout, by avoiding using bufctls which would be just as large as the data itself and cause memory usage to be much greater. Starting at the first address of that page, there are as many buffers as can be allocated without running into the slab header at the end bonwixk the page.

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Advanced Search Include Citations Disambiguate. The slab contains a list of bufctls, which are simply controllers for each buffer that can be allocated a buffer is lalocator memory that the user of a slab allocator would use. If no such location exists, the system allocates a new slab from contiguous physical pages and assigns it to a cache.

Slab allocation – Wikipedia

The allocator also has several statistical and debugging features that can detect a wide range of problems throughout the system. The reason for the large slabs having a different layout from the small slabs is that it allows large slabs to pack better into page-size units, which helps with fragmentation. The allocator’s object caches respond dynamically to global memory pressure, and employ an objectcoloring scheme that improves the system’s overall cache utilization and bus balance.

Views Read Edit View history. A fast kernel memory allocator is therefore essential. The next call to allocate memory of the same size will return the now unused memory slot. Webarchive template wayback links Use dmy dates from August Wikipedia articles needing rewrite from May All articles needing rewrite All articles with unsourced statements Articles with unsourced statements from April Initially, the system marks each slab as “empty”.

With slab allocation, memory chunks suitable to fit data objects of certain type or size are preallocated.