When we want to grab a refcount via get_any_page, we call __get_any_page that calls get_hwpoison_page to get the actual refcount. get_any_page is only there because we have a sort of retry mechanism in case the page we met is unknown to us or if we raced with an allocation.
Also __get_any_page prints some messages about the page type in case the page was a free page or the page type was unknown, but if anything, we only need to print a message in case the pagetype was unknown, as that is reporting an error down the chain. Let us merge get_any_page and __get_any_page, and let the message be printed in soft_offline_page. Signed-off-by: Oscar Salvador <[email protected]> --- mm/memory-failure.c | 91 ++++++++++++++++++--------------------------- 1 file changed, 37 insertions(+), 54 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 869ece2a1de2..0d2323ba4b8e 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1707,70 +1707,49 @@ EXPORT_SYMBOL(unpoison_memory); /* * Safely get reference count of an arbitrary page. - * Returns 0 for a free page, -EIO for a zero refcount page - * that is not free, and 1 for any other page type. - * For 1 the page is returned with increased page count, otherwise not. + * Returns 0 for a free page, 1 for an in-use page, -EIO for a page-type we + * cannot handle and -EBUSY if we raced with an allocation. + * We only incremented refcount in case the page was already in-use and it is + * a known type we can handle. */ -static int __get_any_page(struct page *p, unsigned long pfn, int flags) +static int get_any_page(struct page *p, unsigned long pfn, int flags) { - int ret; + int ret = 0, pass = 0; if (flags & MF_COUNT_INCREASED) return 1; - /* - * When the target page is a free hugepage, just remove it - * from free hugepage list. - */ +try_again: if (!get_hwpoison_page(p)) { - if (PageHuge(p)) { - pr_info("%s: %#lx free huge page\n", __func__, pfn); - ret = 0; - } else if (is_free_buddy_page(p)) { - pr_info("%s: %#lx free buddy page\n", __func__, pfn); - ret = 0; - } else if (page_count(p)) { - /* raced with allocation */ + if (page_count(p)) { + /* We raced with an allocation, retry. */ + if (pass++ < 3) + goto try_again; ret = -EBUSY; - } else { - pr_info("%s: %#lx: unknown zero refcount page type %lx\n", - __func__, pfn, p->flags); + } else if (!PageHuge(p) && !is_free_buddy_page(p)) { + /* We raced with put_page, retry. */ + if (pass++ < 3) + goto try_again; ret = -EIO; } } else { - /* Not a free page */ - ret = 1; - } - return ret; -} - -static int get_any_page(struct page *page, unsigned long pfn, int flags) -{ - int ret = __get_any_page(page, pfn, flags); - - if (ret == -EBUSY) - ret = __get_any_page(page, pfn, flags); - - if (ret == 1 && !PageHuge(page) && - !PageLRU(page) && !__PageMovable(page)) { - /* - * Try to free it. - */ - put_page(page); - shake_page(page, 1); - - /* - * Did it turn free? - */ - ret = __get_any_page(page, pfn, 0); - if (ret == 1 && !PageLRU(page)) { - /* Drop page reference which is from __get_any_page() */ - put_page(page); - pr_info("soft_offline: %#lx: unknown non LRU page type %lx (%pGp)\n", - pfn, page->flags, &page->flags); - return -EIO; + if (PageHuge(p) || PageLRU(p) || __PageMovable(p)) { + ret = 1; + } else { + /* + * A page we cannot handle. Check whether we can turn + * it into something we can handle. + */ + if (pass++ < 3) { + put_page(p); + shake_page(p, 1); + goto try_again; + } + put_page(p); + ret = -EIO; } } + return ret; } @@ -1939,7 +1918,7 @@ int soft_offline_page(unsigned long pfn, int flags) return -EIO; if (PageHWPoison(page)) { - pr_info("soft offline: %#lx page already poisoned\n", pfn); + pr_info("%s: %#lx page already poisoned\n", __func__, pfn); if (flags & MF_COUNT_INCREASED) put_page(page); return 0; @@ -1950,13 +1929,17 @@ int soft_offline_page(unsigned long pfn, int flags) ret = get_any_page(page, pfn, flags); put_online_mems(); - if (ret > 0) + if (ret > 0) { ret = soft_offline_in_use_page(page); - else if (ret == 0) + } else if (ret == 0) { if (soft_offline_free_page(page) && try_again) { try_again = false; goto retry; } + } else if (ret == -EIO) { + pr_info("%s: %#lx: unknown page type: %lx (%pGP)\n", + __func__, pfn, page->flags, &page->flags); + } return ret; } -- 2.26.2
