Messages in this thread | ![/](/images/icornerl.gif) | | Subject | Re: [PATCH] x86: Run checksumming in parallel accross multiple alu's | From | Eric Dumazet <> | Date | Mon, 21 Oct 2013 10:31:38 -0700 |
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On Sun, 2013-10-20 at 17:29 -0400, Neil Horman wrote: > On Fri, Oct 18, 2013 at 02:15:52PM -0700, Eric Dumazet wrote: > > On Fri, 2013-10-18 at 16:11 -0400, Neil Horman wrote: > > > > > #define BUFSIZ_ORDER 4 > > > #define BUFSIZ ((2 << BUFSIZ_ORDER) * (1024*1024*2)) > > > static int __init csum_init_module(void) > > > { > > > int i; > > > __wsum sum = 0; > > > struct timespec start, end; > > > u64 time; > > > struct page *page; > > > u32 offset = 0; > > > > > > page = alloc_pages((GFP_TRANSHUGE & ~__GFP_MOVABLE), BUFSIZ_ORDER); > > > > Not sure what you are doing here, but its not correct. > > > Why not? You asked for a test with 32 hugepages, so I allocated 32 hugepages.
Not really. We cannot allocate 64 Mbytes in a single alloc_pages() call on x86. (MAX_ORDER = 11)
You noticed nothing because you did not write anything on the 64Mbytes area (and corrupt memory) or use CONFIG_DEBUG_PAGEALLOC=y.
Your code read data out of bounds and was lucky, thats all...
You in fact allocated a page of (4096<<4) bytes
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