Re: [PATCH v6 10/10] mm/memory_hotplug: Cleanup __remove_pages()
From: Oscar Salvador <osalvador@suse.de>
Date: 2020-02-04 09:46:59
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linux-mm, linux-s390, linux-sh, linuxppc-dev, lkml
On Sun, Oct 06, 2019 at 10:56:46AM +0200, David Hildenbrand wrote:
Let's drop the basically unused section stuff and simplify. Also, let's use a shorter variant to calculate the number of pages to the next section boundary. Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Dan Williams <redacted> Cc: Wei Yang <redacted> Signed-off-by: David Hildenbrand <redacted>
I have to confess that it took me while to wrap around my head with the new min() change, but looks ok: Reviewed-by: Oscar Salvador <osalvador@suse.de>
quoted hunk ↗ jump to hunk
--- mm/memory_hotplug.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-)diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 843481bd507d..2275240cfa10 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c@@ -490,25 +490,20 @@ static void __remove_section(unsigned long pfn, unsigned long nr_pages, void __remove_pages(unsigned long pfn, unsigned long nr_pages, struct vmem_altmap *altmap) { + const unsigned long end_pfn = pfn + nr_pages; + unsigned long cur_nr_pages; unsigned long map_offset = 0; - unsigned long nr, start_sec, end_sec; map_offset = vmem_altmap_offset(altmap); if (check_pfn_span(pfn, nr_pages, "remove")) return; - start_sec = pfn_to_section_nr(pfn); - end_sec = pfn_to_section_nr(pfn + nr_pages - 1); - for (nr = start_sec; nr <= end_sec; nr++) { - unsigned long pfns; - + for (; pfn < end_pfn; pfn += cur_nr_pages) { cond_resched(); - pfns = min(nr_pages, PAGES_PER_SECTION - - (pfn & ~PAGE_SECTION_MASK)); - __remove_section(pfn, pfns, map_offset, altmap); - pfn += pfns; - nr_pages -= pfns; + /* Select all remaining pages up to the next section boundary */ + cur_nr_pages = min(end_pfn - pfn, -(pfn | PAGE_SECTION_MASK)); + __remove_section(pfn, cur_nr_pages, map_offset, altmap); map_offset = 0; } }-- 2.21.0
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