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authorOscar Salvador <osalvador@suse.de>2020-12-14 19:11:38 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2020-12-15 12:13:44 -0800
commit8295d535e2aa198bdf65a4045d622df38955ffe2 (patch)
tree801068d24a540a04014c1d6c0b0bfa9952cbc4f4 /mm/memory-failure.c
parent32409cba3f66810626c1c15b728c31968d6bfa92 (diff)
downloadlinux-8295d535e2aa198bdf65a4045d622df38955ffe2.tar.bz2
mm,hwpoison: refactor get_any_page
Patch series "HWPoison: Refactor get page interface", v2. This patch (of 3): 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. While we are it, we can also remove the 'pfn' parameter as it is no longer used. Link: https://lkml.kernel.org/r/20201204102558.31607-1-osalvador@suse.de Link: https://lkml.kernel.org/r/20201204102558.31607-2-osalvador@suse.de Signed-off-by: Oscar Salvador <osalvador@suse.de> Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Acked-by: Vlastimil Babka <Vbabka@suse.cz> Cc: Qian Cai <qcai@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory-failure.c')
-rw-r--r--mm/memory-failure.c99
1 files changed, 42 insertions, 57 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 0b8a1017c2e7..a92874a98b60 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1707,70 +1707,51 @@ 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, int flags)
{
- int ret;
+ int ret = 0, pass = 0;
+ bool count_increased = false;
if (flags & MF_COUNT_INCREASED)
- return 1;
+ count_increased = true;
- /*
- * When the target page is a free hugepage, just remove it
- * from free hugepage list.
- */
- 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 */
+try_again:
+ if (!count_increased && !get_hwpoison_page(p)) {
+ 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);
+ count_increased = false;
+ goto try_again;
+ }
+ put_page(p);
+ ret = -EIO;
}
}
+
return ret;
}
@@ -1939,7 +1920,7 @@ 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;
@@ -1947,16 +1928,20 @@ int soft_offline_page(unsigned long pfn, int flags)
retry:
get_online_mems();
- ret = get_any_page(page, pfn, flags);
+ ret = get_any_page(page, 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;
}