* Re: [PATCH] mm, memory_hotplug: Fix the wrong usage of N_HIGH_MEMORY [not found] <20190320080732.14933-1-bhe@redhat.com> @ 2019-03-20 19:12 ` Andrew Morton 2019-03-20 19:53 ` Michal Hocko 0 siblings, 1 reply; 2+ messages in thread From: Andrew Morton @ 2019-03-20 19:12 UTC (permalink / raw) To: Baoquan He Cc: linux-kernel, osalvador, mhocko, david, richard.weiyang, rppt, linux-mm On Wed, 20 Mar 2019 16:07:32 +0800 Baoquan He <bhe@redhat.com> wrote: > In function node_states_check_changes_online(), N_HIGH_MEMORY is used > to substitute ZONE_HIGHMEM directly. This is not right. N_HIGH_MEMORY > always has value '3' if CONFIG_HIGHMEM=y, while ZONE_HIGHMEM's value > is not. It depends on whether CONFIG_ZONE_DMA/CONFIG_ZONE_DMA32 are > enabled. Obviously it's not true for CONFIG_ZONE_DMA32 on 32bit system, > and CONFIG_ZONE_DMA is also optional. > > Replace it with ZONE_HIGHMEM. > > Fixes: 8efe33f40f3e ("mm/memory_hotplug.c: simplify node_states_check_changes_online") What are the runtime effects of this change? > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -712,7 +712,7 @@ static void node_states_check_changes_online(unsigned long nr_pages, > if (zone_idx(zone) <= ZONE_NORMAL && !node_state(nid, N_NORMAL_MEMORY)) > arg->status_change_nid_normal = nid; > #ifdef CONFIG_HIGHMEM > - if (zone_idx(zone) <= N_HIGH_MEMORY && !node_state(nid, N_HIGH_MEMORY)) > + if (zone_idx(zone) <= ZONE_HIGHMEM && !node_state(nid, N_HIGH_MEMORY)) > arg->status_change_nid_high = nid; > #endif > } ^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] mm, memory_hotplug: Fix the wrong usage of N_HIGH_MEMORY 2019-03-20 19:12 ` [PATCH] mm, memory_hotplug: Fix the wrong usage of N_HIGH_MEMORY Andrew Morton @ 2019-03-20 19:53 ` Michal Hocko 0 siblings, 0 replies; 2+ messages in thread From: Michal Hocko @ 2019-03-20 19:53 UTC (permalink / raw) To: Andrew Morton Cc: Baoquan He, linux-kernel, osalvador, david, richard.weiyang, rppt, linux-mm On Wed 20-03-19 12:12:09, Andrew Morton wrote: > On Wed, 20 Mar 2019 16:07:32 +0800 Baoquan He <bhe@redhat.com> wrote: > > > In function node_states_check_changes_online(), N_HIGH_MEMORY is used > > to substitute ZONE_HIGHMEM directly. This is not right. N_HIGH_MEMORY > > always has value '3' if CONFIG_HIGHMEM=y, while ZONE_HIGHMEM's value > > is not. It depends on whether CONFIG_ZONE_DMA/CONFIG_ZONE_DMA32 are > > enabled. Obviously it's not true for CONFIG_ZONE_DMA32 on 32bit system, > > and CONFIG_ZONE_DMA is also optional. > > > > Replace it with ZONE_HIGHMEM. > > > > Fixes: 8efe33f40f3e ("mm/memory_hotplug.c: simplify node_states_check_changes_online") > > What are the runtime effects of this change? There shouldn't be none. The code is just messy. The newer changelog should make it more clear I believe. > > --- a/mm/memory_hotplug.c > > +++ b/mm/memory_hotplug.c > > @@ -712,7 +712,7 @@ static void node_states_check_changes_online(unsigned long nr_pages, > > if (zone_idx(zone) <= ZONE_NORMAL && !node_state(nid, N_NORMAL_MEMORY)) > > arg->status_change_nid_normal = nid; > > #ifdef CONFIG_HIGHMEM > > - if (zone_idx(zone) <= N_HIGH_MEMORY && !node_state(nid, N_HIGH_MEMORY)) > > + if (zone_idx(zone) <= ZONE_HIGHMEM && !node_state(nid, N_HIGH_MEMORY)) > > arg->status_change_nid_high = nid; > > #endif > > } > -- Michal Hocko SUSE Labs ^ permalink raw reply [flat|nested] 2+ messages in thread
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2019-03-20 19:12 ` [PATCH] mm, memory_hotplug: Fix the wrong usage of N_HIGH_MEMORY Andrew Morton
2019-03-20 19:53 ` Michal Hocko
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