Messages in this thread | | | Date | Mon, 11 Jan 2016 11:14:34 -0800 | From | Alexei Starovoitov <> | Subject | Re: [PATCH 6/9] bpf: arraymap: introduce BPF_MAP_TYPE_ARRAY_PERCPU |
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On Mon, Jan 11, 2016 at 11:56:58PM +0800, Ming Lei wrote: > This patch introduces percpu array map so that expensive > atomic operations can be avoided in eBPF prog in case of > ARRAY map. > > PERCPU MAP uses the percpu version of update/lookup element > helpers and callbacks to access element in the map, and > the previous update/lookup element helpers and callbacks > don't work at the same time. > > Signed-off-by: Ming Lei <tom.leiming@gmail.com>
useful stuff!
> + if (percpu) { > + if (alloc_percpu_array(array, attr->max_entries, > + attr->value_size)) { > + kvfree(array); > + return ERR_PTR(-ENOMEM); > + } > + array->map.pages = round_up(attr->max_entries * > + attr->value_size * num_possible_cpus(), > + PAGE_SIZE) >> PAGE_SHIFT;
I think it would be more accurate to add it to array_size instead of doing page rounding here.
> - array->map.pages = round_up(array_size, PAGE_SIZE) >> PAGE_SHIFT; > + array->map.pages += round_up(array_size, PAGE_SIZE) >> PAGE_SHIFT;
and this line wouldn't need to change...
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