Messages in this thread Patch in this message | | | From | Wei Yang <> | Date | Thu, 3 Aug 2017 15:12:59 +0800 | Subject | Re: [PATCH] x86/mm: trivial code cleanup for memory_map_top_doown() |
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Hmm.... ping...
On Tue, May 2, 2017 at 9:26 PM, Wei Yang <richard.weiyang@gmail.com> wrote: > Hi, Borislav and all > > Do you agree with my analysis or you have other comments? > > On Tue, Mar 14, 2017 at 11:56:39AM +0800, Wei Yang wrote: >>On Mon, Mar 13, 2017 at 07:50:21PM +0100, Borislav Petkov wrote: >>>On Fri, Feb 17, 2017 at 10:30:33PM +0800, Wei Yang wrote: >>>> In case (last_start <= step_size), start is for sure to be 0. So, it is >>> >> >>Hmm, I may write it more specific: >> >>"start" is for sure to be set to 0 with round_down(last_start - 1, step_size). >> >>>Well, lemme see: >>> >>>[ 0.000000] memory_map_top_down: entry, [0x100000:0x7ffdf000) >>>[ 0.000000] memory_map_top_down: addr: 0x7fc00000, real_end: 0x7fe00000 >>>[ 0.000000] memory_map_top_down: last_start: 0x40000000 <= step_size: 0x2000000000, start: 0x40000000 >>> ^^^^^^^^^^ >>>It doesn't look like 0 to me. >>> >>>--- >>>diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c >>>index 2193799ca800..d3b02a416df3 100644 >>>--- a/arch/x86/mm/init.c >>>+++ b/arch/x86/mm/init.c >>>@@ -527,8 +531,13 @@ static void __init memory_map_top_down(unsigned long map_start, >>> start = round_down(last_start - 1, step_size); >>> if (start < map_start) >>> start = map_start; >>>- } else >>>+ } else { >>>+ pr_info("%s: last_start: 0x%lx <= step_size: 0x%lx, start: 0x%lx\n", >>>+ __func__, last_start, step_size, start); >>>+ >> >>If you change this log with the following >> >> pr_err("%s: last_start: 0x%lx <= step_size: 0x%lx, start: 0x%lx\n", >> __func__, last_start, step_size, >> round_down(last_start - 1, step_size)); >> >>You could see after calculation, start is 0 when (last_start <= step_size). >> >>-- >>Wei Yang >>Help you, Help me > > > > -- > Wei Yang > Help you, Help me
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