[PATCH v3 3/4] arm64: kdump: support more than one crash kernel regions
rppt at linux.ibm.com
Sun Apr 14 22:04:18 PDT 2019
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 :(
> Chen Zhou
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