| Message ID | 20181211142741.2607-2-mhocko@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | few memory offlining enhancements | expand |
On Tue, Dec 11, 2018 at 03:27:39PM +0100, Michal Hocko wrote: >From: Michal Hocko <mhocko@suse.com> > >do_migrate_range has been limiting the number of pages to migrate to 256 >for some reason which is not documented. Even if the limit made some >sense back then when it was introduced it doesn't really serve a good >purpose these days. If the range contains huge pages then >we break out of the loop too early and go through LRU and pcp >caches draining and scan_movable_pages is quite suboptimal. > >The only reason to limit the number of pages I can think of is to reduce >the potential time to react on the fatal signal. But even then the >number of pages is a questionable metric because even a single page >might migration block in a non-killable state (e.g. __unmap_and_move). > >Remove the limit and offline the full requested range (this is one >membblock worth of pages with the current code). Should we ever get a s/membblock/memblock/ Or memory block is more accurate? May memblock confuse audience with lower level facility? >report that offlining takes too long to react on fatal signal then we >should rather fix the core migration to use killable waits and bailout >on a signal. > >Reviewed-by: David Hildenbrand <david@redhat.com> >Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com> >Reviewed-by: Oscar Salvador <osalvador@suse.de> >Signed-off-by: Michal Hocko <mhocko@suse.com> >--- > mm/memory_hotplug.c | 8 ++------ > 1 file changed, 2 insertions(+), 6 deletions(-) > >diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c >index c82193db4be6..6263c8cd4491 100644 >--- a/mm/memory_hotplug.c >+++ b/mm/memory_hotplug.c >@@ -1339,18 +1339,16 @@ static struct page *new_node_page(struct page *page, unsigned long private) > return new_page_nodemask(page, nid, &nmask); > } > >-#define NR_OFFLINE_AT_ONCE_PAGES (256) > static int > do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) > { > unsigned long pfn; > struct page *page; >- int move_pages = NR_OFFLINE_AT_ONCE_PAGES; > int not_managed = 0; > int ret = 0; > LIST_HEAD(source); > >- for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) { >+ for (pfn = start_pfn; pfn < end_pfn; pfn++) { > if (!pfn_valid(pfn)) > continue; > page = pfn_to_page(pfn); >@@ -1362,8 +1360,7 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) > ret = -EBUSY; > break; > } >- if (isolate_huge_page(page, &source)) >- move_pages -= 1 << compound_order(head); >+ isolate_huge_page(page, &source); > continue; > } else if (PageTransHuge(page)) > pfn = page_to_pfn(compound_head(page)) >@@ -1382,7 +1379,6 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) > if (!ret) { /* Success */ > put_page(page); > list_add_tail(&page->lru, &source); >- move_pages--; > if (!__PageMovable(page)) > inc_node_page_state(page, NR_ISOLATED_ANON + > page_is_file_cache(page)); >-- >2.19.2
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index c82193db4be6..6263c8cd4491 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1339,18 +1339,16 @@ static struct page *new_node_page(struct page *page, unsigned long private) return new_page_nodemask(page, nid, &nmask); } -#define NR_OFFLINE_AT_ONCE_PAGES (256) static int do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) { unsigned long pfn; struct page *page; - int move_pages = NR_OFFLINE_AT_ONCE_PAGES; int not_managed = 0; int ret = 0; LIST_HEAD(source); - for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) { + for (pfn = start_pfn; pfn < end_pfn; pfn++) { if (!pfn_valid(pfn)) continue; page = pfn_to_page(pfn); @@ -1362,8 +1360,7 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) ret = -EBUSY; break; } - if (isolate_huge_page(page, &source)) - move_pages -= 1 << compound_order(head); + isolate_huge_page(page, &source); continue; } else if (PageTransHuge(page)) pfn = page_to_pfn(compound_head(page)) @@ -1382,7 +1379,6 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) if (!ret) { /* Success */ put_page(page); list_add_tail(&page->lru, &source); - move_pages--; if (!__PageMovable(page)) inc_node_page_state(page, NR_ISOLATED_ANON + page_is_file_cache(page));