Messages in this thread | | | Subject | Re: [PATCH v5 4/4] mm/sparse: Optimize memmap allocation during sparse_init() | From | Pavel Tatashin <> | Date | Fri, 29 Jun 2018 14:01:14 -0400 |
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On 06/29/2018 01:52 PM, Dave Hansen wrote: > On 06/29/2018 10:48 AM, Pavel Tatashin wrote: >> Here is example: >> Node1: >> map_map[0] -> Struct pages ... >> map_map[1] -> NULL >> Node2: >> map_map[2] -> Struct pages ... >> >> We always want to configure section from Node2 with struct pages from >> Node2. Even, if there are holes in-between. The same with usemap. > > Right... But your example consumes two mem_map[]s. > > But, from scanning the code, we increment nr_consumed_maps three times. > Correct?
Correct: it should be incremented on every iteration of the loop. No matter if the entries contained valid data or NULLs. So we increment in three places:
if map_map[] has invalid entry, increment, continue if usemap_map[] has invalid entry, increment, continue at the end of the loop, everything was valid we increment it
This is done so nr_consumed_maps does not get out of sync with the current pnum. pnum does not equal to nr_consumed_maps, as there are may be holes in pnums, but there is one-to-one correlation.
Pavel
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