diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/memory_hotplug.c | 81 | ||||
| -rw-r--r-- | mm/page_alloc.c | 26 | ||||
| -rw-r--r-- | mm/page_isolation.c | 9 |
3 files changed, 106 insertions, 10 deletions
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index c4d5c45820d0..9b34e03e730a 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1201,11 +1201,17 @@ struct zone *test_pages_in_a_zone(unsigned long start_pfn, /* * Scan pfn range [start,end) to find movable/migratable pages (LRU pages, - * non-lru movable pages and hugepages). We scan pfn because it's much - * easier than scanning over linked list. This function returns the pfn - * of the first found movable page if it's found, otherwise 0. + * non-lru movable pages and hugepages). Will skip over most unmovable + * pages (esp., pages that can be skipped when offlining), but bail out on + * definitely unmovable pages. + * + * Returns: + * 0 in case a movable page is found and movable_pfn was updated. + * -ENOENT in case no movable page was found. + * -EBUSY in case a definitely unmovable page was found. */ -static unsigned long scan_movable_pages(unsigned long start, unsigned long end) +static int scan_movable_pages(unsigned long start, unsigned long end, + unsigned long *movable_pfn) { unsigned long pfn; @@ -1217,18 +1223,30 @@ static unsigned long scan_movable_pages(unsigned long start, unsigned long end) continue; page = pfn_to_page(pfn); if (PageLRU(page)) - return pfn; + goto found; if (__PageMovable(page)) - return pfn; + goto found; + + /* + * PageOffline() pages that are not marked __PageMovable() and + * have a reference count > 0 (after MEM_GOING_OFFLINE) are + * definitely unmovable. If their reference count would be 0, + * they could at least be skipped when offlining memory. + */ + if (PageOffline(page) && page_count(page)) + return -EBUSY; if (!PageHuge(page)) continue; head = compound_head(page); if (page_huge_active(head)) - return pfn; + goto found; skip = compound_nr(head) - (page - head); pfn += skip - 1; } + return -ENOENT; +found: + *movable_pfn = pfn; return 0; } @@ -1491,7 +1509,8 @@ static int __ref __offline_pages(unsigned long start_pfn, } do { - for (pfn = start_pfn; pfn;) { + pfn = start_pfn; + do { if (signal_pending(current)) { ret = -EINTR; reason = "signal backoff"; @@ -1501,14 +1520,19 @@ static int __ref __offline_pages(unsigned long start_pfn, cond_resched(); lru_add_drain_all(); - pfn = scan_movable_pages(pfn, end_pfn); - if (pfn) { + ret = scan_movable_pages(pfn, end_pfn, &pfn); + if (!ret) { /* * TODO: fatal migration failures should bail * out */ do_migrate_range(pfn, end_pfn); } + } while (!ret); + + if (ret != -ENOENT) { + reason = "unmovable page"; + goto failed_removal_isolated; } /* @@ -1774,4 +1798,41 @@ int remove_memory(int nid, u64 start, u64 size) return rc; } EXPORT_SYMBOL_GPL(remove_memory); + +/* + * Try to offline and remove a memory block. Might take a long time to + * finish in case memory is still in use. Primarily useful for memory devices + * that logically unplugged all memory (so it's no longer in use) and want to + * offline + remove the memory block. + */ +int offline_and_remove_memory(int nid, u64 start, u64 size) +{ + struct memory_block *mem; + int rc = -EINVAL; + + if (!IS_ALIGNED(start, memory_block_size_bytes()) || + size != memory_block_size_bytes()) + return rc; + + lock_device_hotplug(); + mem = find_memory_block(__pfn_to_section(PFN_DOWN(start))); + if (mem) + rc = device_offline(&mem->dev); + /* Ignore if the device is already offline. */ + if (rc > 0) + rc = 0; + + /* + * In case we succeeded to offline the memory block, remove it. + * This cannot fail as it cannot get onlined in the meantime. + */ + if (!rc) { + rc = try_remove_memory(nid, start, size); + WARN_ON_ONCE(rc); + } + unlock_device_hotplug(); + + return rc; +} +EXPORT_SYMBOL_GPL(offline_and_remove_memory); #endif /* CONFIG_MEMORY_HOTREMOVE */ diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 727751219003..48eb0f1410d4 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -8285,6 +8285,19 @@ struct page *has_unmovable_pages(struct zone *zone, struct page *page, if ((flags & MEMORY_OFFLINE) && PageHWPoison(page)) continue; + /* + * We treat all PageOffline() pages as movable when offlining + * to give drivers a chance to decrement their reference count + * in MEM_GOING_OFFLINE in order to indicate that these pages + * can be offlined as there are no direct references anymore. + * For actually unmovable PageOffline() where the driver does + * not support this, we will fail later when trying to actually + * move these pages that still have a reference count > 0. + * (false negatives in this function only) + */ + if ((flags & MEMORY_OFFLINE) && PageOffline(page)) + continue; + if (__PageMovable(page) || PageLRU(page)) continue; @@ -8516,6 +8529,7 @@ done: pfn_max_align_up(end), migratetype); return ret; } +EXPORT_SYMBOL(alloc_contig_range); static int __alloc_contig_pages(unsigned long start_pfn, unsigned long nr_pages, gfp_t gfp_mask) @@ -8631,6 +8645,7 @@ void free_contig_range(unsigned long pfn, unsigned int nr_pages) } WARN(count != 0, "%d pages are still in use!\n", count); } +EXPORT_SYMBOL(free_contig_range); /* * The zone indicated has a new number of managed_pages; batch sizes and percpu @@ -8703,6 +8718,17 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) offlined_pages++; continue; } + /* + * At this point all remaining PageOffline() pages have a + * reference count of 0 and can simply be skipped. + */ + if (PageOffline(page)) { + BUG_ON(page_count(page)); + BUG_ON(PageBuddy(page)); + pfn++; + offlined_pages++; + continue; + } BUG_ON(page_count(page)); BUG_ON(!PageBuddy(page)); diff --git a/mm/page_isolation.c b/mm/page_isolation.c index 2c11a38d6e87..f6d07c5f0d34 100644 --- a/mm/page_isolation.c +++ b/mm/page_isolation.c @@ -151,6 +151,7 @@ __first_valid_page(unsigned long pfn, unsigned long nr_pages) * a bit mask) * MEMORY_OFFLINE - isolate to offline (!allocate) memory * e.g., skip over PageHWPoison() pages + * and PageOffline() pages. * REPORT_FAILURE - report details about the failure to * isolate the range * @@ -259,6 +260,14 @@ __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn, else if ((flags & MEMORY_OFFLINE) && PageHWPoison(page)) /* A HWPoisoned page cannot be also PageBuddy */ pfn++; + else if ((flags & MEMORY_OFFLINE) && PageOffline(page) && + !page_count(page)) + /* + * The responsible driver agreed to skip PageOffline() + * pages when offlining memory by dropping its + * reference in MEM_GOING_OFFLINE. + */ + pfn++; else break; } |