51 строка
3.3 KiB
Plaintext
51 строка
3.3 KiB
Plaintext
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# Copyright (c) 2013 Mellanox Technologies, Inc.
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# All rights reserved
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# $COPYRIGHT$
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MEMHEAP Infrustructure documentation
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------------------------------------
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MEMHEAP Infrustructure is responsible for managing the symmetric heap.
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The framework currently has following components: buddy and ptmalloc. buddy which uses a buddy allocator in order to manage the Memory allocations on the symmetric heap. Ptmalloc is an adaptation of ptmalloc3.
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Additional components may be added easily to the framework by defining the component's and the module's base and extended structures, and their funtionalities.
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The buddy allocator has the following data structures:
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1. Base component - of type struct mca_memheap_base_component_2_0_0_t
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2. Base module - of type struct mca_memheap_base_module_t
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3. Buddy component - of type struct mca_memheap_base_component_2_0_0_t
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4. Buddy module - of type struct mca_memheap_buddy_module_t extending the base module (struct mca_memheap_base_module_t)
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Each data structure includes the following fields:
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1. Base component - memheap_version, memheap_data and memheap_init
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2. Base module - Holds pointers to the base component and to the functions: alloc, free and finalize
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3. Buddy component - is a base component.
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4. Buddy module - Extends the base module and holds additional data on the components's priority, buddy allocator,
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maximal order of the symmetric heap, symmetric heap, pointer to the symmetric heap and hashtable maintaining the size of each allocated address.
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In the case that the user decides to implement additional components, the Memheap infrastructure chooses a component with the maximal priority.
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Handling the component opening is done under the base directory, in three stages:
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1. Open all available components. Implemented by memheap_base_open.c and called from shmem_init.
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2. Select the maximal priority component. This procedure involves the initialization of all components and then their
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finalization except to the chosen component. It is implemented by memheap_base_select.c and called from shmem_init.
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3. Close the max priority active cmponent. Implemented by memheap_base_close.c and called from shmem finalize.
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Buddy Component/Module
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----------------------
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Responsible for handling the entire activities of the symmetric heap.
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The supported activities are:
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- buddy_init (Initialization)
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- buddy_alloc (Allocates a variable on the symmetric heap)
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- buddy_free (frees a variable previously allocated on the symetric heap)
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- buddy_finalize (Finalization).
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Data members of buddy module: - priority. The module's priority.
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- buddy allocator: bits, num_free, lock and the maximal order (log2 of the maximal size)
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of a variable on the symmetric heap. Buddy Allocator gives the offset in the symmetric heap
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where a variable should be allocated.
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- symmetric_heap: a range of reserved addresses (equal in all executing PE's) dedicated to "shared memory" allocation.
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- symmetric_heap_hashtable (holding the size of an allocated variable on the symmetric heap.
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used to free an allocated variable on the symmetric heap)
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