On Thu 08-11-18 13:53:18, Arun KS wrote: > Now totalram_pages and managed_pages are atomic varibles. No need > of managed_page_count spinlock. As explained earlier. Please add a motivation here. Feel free to reuse wording from http://lkml.kernel.org/r/20181107103630.GF2453@xxxxxxxxxxxxxx > > Signed-off-by: Arun KS <arunks@xxxxxxxxxxxxxx> > Reviewed-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx> > Acked-by: Michal Hocko <mhocko@xxxxxxxx> > Acked-by: Vlastimil Babka <vbabka@xxxxxxx> > --- > include/linux/mmzone.h | 6 ------ > mm/page_alloc.c | 5 ----- > 2 files changed, 11 deletions(-) > > diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h > index e73dc31..c71b4d9 100644 > --- a/include/linux/mmzone.h > +++ b/include/linux/mmzone.h > @@ -428,12 +428,6 @@ struct zone { > * Write access to present_pages at runtime should be protected by > * mem_hotplug_begin/end(). Any reader who can't tolerant drift of > * present_pages should get_online_mems() to get a stable value. > - * > - * Read access to managed_pages should be safe because it's unsigned > - * long. Write access to zone->managed_pages and totalram_pages are > - * protected by managed_page_count_lock at runtime. Idealy only > - * adjust_managed_page_count() should be used instead of directly > - * touching zone->managed_pages and totalram_pages. > */ > atomic_long_t managed_pages; > unsigned long spanned_pages; > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index f8b64cc..26c5e14 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -122,9 +122,6 @@ > }; > EXPORT_SYMBOL(node_states); > > -/* Protect totalram_pages and zone->managed_pages */ > -static DEFINE_SPINLOCK(managed_page_count_lock); > - > atomic_long_t _totalram_pages __read_mostly; > EXPORT_SYMBOL(_totalram_pages); > unsigned long totalreserve_pages __read_mostly; > @@ -7065,14 +7062,12 @@ static int __init cmdline_parse_movablecore(char *p) > > void adjust_managed_page_count(struct page *page, long count) > { > - spin_lock(&managed_page_count_lock); > atomic_long_add(count, &page_zone(page)->managed_pages); > totalram_pages_add(count); > #ifdef CONFIG_HIGHMEM > if (PageHighMem(page)) > totalhigh_pages_add(count); > #endif > - spin_unlock(&managed_page_count_lock); > } > EXPORT_SYMBOL(adjust_managed_page_count); > > -- > 1.9.1 -- Michal Hocko SUSE Labs
