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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Feb 06, 2020 at 07:08:26AM +0800, Baoquan He wrote: >On 02/06/20 at 06:56am, Wei Yang wrote: >> On Wed, Feb 05, 2020 at 10:48:11PM +0800, Baoquan He wrote: >> >Hi Wei Yang, >> > >> >On 02/05/20 at 05:59pm, Wei Yang wrote: >> >> >diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c >> >> >index f294918f7211..8dafa1ba8d9f 100644 >> >> >--- a/mm/memory_hotplug.c >> >> >+++ b/mm/memory_hotplug.c >> >> >@@ -393,6 +393,9 @@ static void shrink_zone_span(struct zone *zone, unsigned long start_pfn, >> >> > if (pfn) { >> >> > zone->zone_start_pfn = pfn; >> >> > zone->spanned_pages = zone_end_pfn - pfn; >> >> >+ } else { >> >> >+ zone->zone_start_pfn = 0; >> >> >+ zone->spanned_pages = 0; >> >> > } >> >> > } else if (zone_end_pfn == end_pfn) { >> >> > /* >> >> >@@ -405,34 +408,11 @@ static void shrink_zone_span(struct zone *zone, unsigned long start_pfn, >> >> > start_pfn); >> >> > if (pfn) >> >> > zone->spanned_pages = pfn - zone_start_pfn + 1; >> >> >+ else { >> >> >+ zone->zone_start_pfn = 0; >> >> >+ zone->spanned_pages = 0; >> >> >+ } >> >> > } >> >> >> >> If it is me, I would like to take out these two similar logic out. >> > >> >I also like this style. >> >> >> >> For example: >> >> >> >> if () { >> >> } else if () { >> >> } else { >> >> goto out; >> >Here the last else is unnecessary, right? >> > >> >> I am afraid not. >> >> If the range is not the first or last, we would leave pfn not initialized. > >Ah, you are right. I forgot that one. Then pfn can be assigned the >zone_start_pfn as the old code. Then the following logic is the same >as the original code, find_smallest_section_pfn()/find_biggest_section_pfn() >have done the iteration the old for loop was doing. > > unsigned long pfn = zone_start_pfn; > if () { > } else if () { > } > > /* The zone has no valid section */ > if (!pfn) { > zone->zone_start_pfn = 0; > zone->spanned_pages = 0; > } This one look better :-) Thanks -- Wei Yang Help you, Help me _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel