Hi all
I have been playing with PACKET_MMAP to see the amount of memory could
handle
Looking at the source code (2.6), the setup funcion ends by calling
__get_free_pages to allocate a number of contiguous memory for a block
of tp_block_size size.
In my tests I always used a req.tp_frame_size of 2048 and a
tp_block_size of 4096, so in each block can hold two frames.
In my allocation tests I always begin trying to allocate an insane
amount of frames req.tp_frame_nr, if setup fails I reduce it the amount
of frames and I try again.
I always setup the number of blocks needed (tp_block_nr) to hold
the number of frames I want to allocate (tp_frame_nr)
In my tests always end by allocating "only" 64MB of frames
this is a i386 machine (Pentium-III) with 1GB of RAM, mostly free.
who imposes this limit? __get_free_pages is called with GFP_KERNEL,
so I understand it can free other page frames, swap, etc... in order
to allocate more memory
any comments?
Thanks
Debian GNU/Linux: a dream come true
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