Messages in this thread | | | Date | Mon, 15 Apr 2019 08:04:18 +0300 | From | Mike Rapoport <> | Subject | Re: [PATCH v3 3/4] arm64: kdump: support more than one crash kernel regions |
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Hi,
On Mon, Apr 15, 2019 at 10:05:18AM +0800, Chen Zhou wrote: > Hi Mike, > > On 2019/4/14 20:10, Mike Rapoport wrote: > >> > >> solution A: phys_addr_t start[INIT_MEMBLOCK_RESERVED_REGIONS * 2]; > >> phys_addr_t end[INIT_MEMBLOCK_RESERVED_REGIONS * 2]; > >> start, end is physical addr > >> > >> solution B: int start_rgn[INIT_MEMBLOCK_REGIONS], end_rgn[INIT_MEMBLOCK_REGIONS]; > >> start_rgn, end_rgn is rgn index > >> > >> Solution B do less remove operations and with no warning comparing to solution A. > >> I think solution B is better, could you give some suggestions? > > > > Solution B is indeed better that solution A, but I'm still worried by > > relatively large arrays on stack and the amount of loops :( > > > > The very least we could do is to call memblock_cap_memory_range() to drop > > the memory before and after the ranges we'd like to keep. > > 1. relatively large arrays > As my said above, the start_rgn, end_rgn is rgn index, we could use unsigned char type.
Let's stick to int for now
> 2. loops > Loops always exist, and the solution with fewer loops may be just encapsulated well.
Of course the loops are there, I just hoped we could get rid of the nested loop and get away with single passes in all the cases. Apparently it's not the case :(
> Thanks, > Chen Zhou >
-- Sincerely yours, Mike.
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