65 lines
3.3 KiB
Plaintext
65 lines
3.3 KiB
Plaintext
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Tool Name
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===========================================================
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page-nom
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Description
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===========================================================
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page-nom is a memory eater. It can be used to finely allocate large amounts of
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system or vmalloc memory in order to better test applications in low memory
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situations. Memory is allocated in individual blocks of a given size which can
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be tuned. By allocating in chunks it makes it more likely that we can allocate
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as close to the full request as possible and also makes it easy to dynamically
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add and remove blocks without having to free and re-initalize (with all the
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panic that might entail on a system wide basis). New memory is allocated by
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specifying how many chunks one wants allocated. This all happens via debugfs.
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Input
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===========================================================
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- /sys/kernel/debug/page-nom/vmalloc_block_size
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size in bytes of the individual blocks of memory allocated from vmalloc. The
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input size is page aligned. The block size can only be changed when page-nom
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hasn't eaten any vmalloc pages yet.
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- /sys/kernel/debug/page-nom/vmalloc_blocks
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number of 'vmalloc_block_size' blocks to eat from vmalloc. Inputing a number
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higher than the current value will allocate new memory and inputing a number
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lower than the current value will free memory. 0 will free all eaten vmalloc
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memory. The returned value will be the number of allocated blocks regardless
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if this method or the following method was used to allocate the blocks.
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- /sys/kernel/debug/page-nom/vmalloc_percent
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percentage of the vmalloc memory to eat. This is an alternate method to
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'vmalloc_blocks'. Where vmalloc_blocks is more precise, this is easier for
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automation. Just echo a number between 0 and 100 for page-nom to try to consume
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that percentage of total vmalloc memory. The returned value from this file
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is the current percentage of allocated vmalloc memory from either method. This
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number will be appropriately massaged so it ends up being a multiple of
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vmalloc_block_size, so the number written won't always be the precise
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percentage eaten.
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- /sys/kernel/debug/page-nom/mem_block_size
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size in bytes of the individual blocks of memory allocated from memory.
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The input size is order aligned. The block size can only be changed when
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page-nom hasn't eaten any pages yet.
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- /sys/kernel/debug/page-nom/mem_blocks
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number of 'mem_block_size' blocks to eat from memory. Inputing a number higher
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than the current value will allocate new memory and inputing a number lower than
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the current value will free memory. 0 will free all eaten vmalloc memory. The
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returned value will be the number of allocated blocks regardless if this method
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or the following method was used to allocate the blocks.
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- /sys/kernel/debug/page-nom/mem_percent - percentage of the system memory to
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eat. This is an alternate method to 'mem_blocks'. Where mem_blocks is more
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precise, this is easier for automation. Just echo a number between 0 and 100
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for page-nom to try to consume that percentage of system memory. The returned
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value from this file is the current percentage of allocated system memory from
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either method. This number will be appropriately massaged so it ends up being
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a multiple of mem_block_size, so the number written won't always be the precise
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percentage eaten.
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Targets
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===========================================================
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General
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