On Fri, Jun 26, 2020 at 10:23:43PM +0530, Naresh Kamboju wrote:

On Wed, 24 Jun 2020 at 20:32, nao.horiguchi@gmail.com wrote:

...

From: Oscar Salvador osalvador@suse.de

Merging soft_offline_huge_page and __soft_offline_page let us get rid of quite some duplicated code, and makes the code much easier to follow.

Now, __soft_offline_page will handle both normal and hugetlb pages.

Note that move put_page() block to the beginning of page_handle_poison() with drain_all_pages() in order to make sure that the target page is freed and sent into free list to make take_page_off_buddy() work properly.

Signed-off-by: Oscar Salvador osalvador@suse.de Signed-off-by: Naoya Horiguchi naoya.horiguchi@nec.com

---

ChangeLog v2 -> v3:

• use page_is_file_lru() instead of page_is_file_cache(),
• add description about put_page() and drain_all_pages().
• fix coding style warnings by checkpatch.pl

---

mm/memory-failure.c | 185 ++++++++++++++++++++------------------------ 1 file changed, 86 insertions(+), 99 deletions(-)

diff --git v5.8-rc1-mmots-2020-06-20-21-44/mm/memory-failure.c v5.8-rc1-mmots-2020-06-20-21-44_patched/mm/memory-failure.c index f744eb90c15c..22c904f6d17a 100644 --- v5.8-rc1-mmots-2020-06-20-21-44/mm/memory-failure.c +++ v5.8-rc1-mmots-2020-06-20-21-44_patched/mm/memory-failure.c @@ -78,14 +78,36 @@ EXPORT_SYMBOL_GPL(hwpoison_filter_dev_minor); EXPORT_SYMBOL_GPL(hwpoison_filter_flags_mask); EXPORT_SYMBOL_GPL(hwpoison_filter_flags_value);

-static void page_handle_poison(struct page *page, bool release) +static bool page_handle_poison(struct page *page, bool hugepage_or_freepage, bool release) {

•   if (release) {
  

•           put_page(page);
  

•           drain_all_pages(page_zone(page));
  

•   }
  

•   if (hugepage_or_freepage) {
  

•           /*
  

•            * Doing this check for free pages is also fine since dissolve_free_huge_page
  

•            * returns 0 for non-hugetlb pages as well.
  

•            */
  

•           if (dissolve_free_huge_page(page) || !take_page_off_buddy(page))
  

•           /*
  

•            * The hugetlb page can end up being enqueued back into
  

•            * the freelists by means of:
  

•            * unmap_and_move_huge_page
  

•            *  putback_active_hugepage
  

•            *   put_page->free_huge_page
  

•            *    enqueue_huge_page
  

•            * If this happens, we might lose the race against an allocation.
  

•            */
  

•                   return false;
  

•   }
  
    SetPageHWPoison(page);
  

•   if (release)
  

•           put_page(page);
    page_ref_inc(page);
    num_poisoned_pages_inc();
  

•   return true;
  

}

static int hwpoison_filter_dev(struct page *p) @@ -1718,63 +1740,52 @@ static int get_any_page(struct page *page, unsigned long pfn) return ret; }

-static int soft_offline_huge_page(struct page *page) +static bool isolate_page(struct page *page, struct list_head *pagelist) {

•   int ret;
  

•   unsigned long pfn = page_to_pfn(page);
  

•   struct page *hpage = compound_head(page);
  

•   LIST_HEAD(pagelist);
  

•   bool isolated = false;
  

•   bool lru = PageLRU(page);
  

•   if (PageHuge(page)) {
  

•           isolated = isolate_huge_page(page, pagelist);
  

•   } else {
  

•           if (lru)
  

•                   isolated = !isolate_lru_page(page);
  

•           else
  

•                   isolated = !isolate_movable_page(page, ISOLATE_UNEVICTABLE);
  

•           if (isolated)
  

•                   list_add(&page->lru, pagelist);
  
  

•   /*
  

•    * This double-check of PageHWPoison is to avoid the race with
  

•    * memory_failure(). See also comment in __soft_offline_page().
  

•    */
  

•   lock_page(hpage);
  

•   if (PageHWPoison(hpage)) {
  

•           unlock_page(hpage);
  

•           put_page(hpage);
  

•           pr_info("soft offline: %#lx hugepage already poisoned\n", pfn);
  

•           return -EBUSY;
    }
  

•   unlock_page(hpage);
  
  

•   ret = isolate_huge_page(hpage, &pagelist);
  

•   if (isolated && lru)
  

•           inc_node_page_state(page, NR_ISOLATED_ANON +
  

•                               page_is_file_lru(page));
  

•   /*
  

•    * get_any_page() and isolate_huge_page() takes a refcount each,
  

•    * so need to drop one here.
  

•    * If we succeed to isolate the page, we grabbed another refcount on
  

•    * the page, so we can safely drop the one we got from get_any_pages().
  

•    * If we failed to isolate the page, it means that we cannot go further
  

•    * and we will return an error, so drop the reference we got from
  

•    * get_any_pages() as well.
     */
  

•   put_page(hpage);
  

•   if (!ret) {
  

•           pr_info("soft offline: %#lx hugepage failed to isolate\n", pfn);
  

•           return -EBUSY;
  

•   }
  

•   ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL,
  

•                           MIGRATE_SYNC, MR_MEMORY_FAILURE);
  

•   if (ret) {
  

•           pr_info("soft offline: %#lx: hugepage migration failed %d, type %lx (%pGp)\n",
  

•                   pfn, ret, page->flags, &page->flags);
  

•           if (!list_empty(&pagelist))
  

•                   putback_movable_pages(&pagelist);
  

•           if (ret > 0)
  

•                   ret = -EIO;
  

•   } else {
  

•           /*
  

•            * We set PG_hwpoison only when we were able to take the page
  

•            * off the buddy.
  

•            */
  

•           if (!dissolve_free_huge_page(page) && take_page_off_buddy(page))
  

•                   page_handle_poison(page, false);
  

•           else
  

•                   ret = -EBUSY;
  

•   }
  

•   return ret;
  

•   put_page(page);
  

•   return isolated;
  

}

+/*

• • __soft_offline_page handles hugetlb-pages and non-hugetlb pages.
• • If the page is a non-dirty unmapped page-cache page, it simply invalidates.
• • If the page is mapped, it migrates the contents over.
• */

static int __soft_offline_page(struct page *page) {

•   int ret;
  

•   int ret = 0;
    unsigned long pfn = page_to_pfn(page);
  

•   struct page *hpage = compound_head(page);
  

•   const char *msg_page[] = {"page", "hugepage"};
  

•   bool huge = PageHuge(page);
  

•   LIST_HEAD(pagelist);
  
    /*
     * Check PageHWPoison again inside page lock because PageHWPoison
  

@@ -1783,98 +1794,74 @@ static int __soft_offline_page(struct page *page) * so there's no race between soft_offline_page() and memory_failure(). */ lock_page(page);

•   wait_on_page_writeback(page);
  

•   if (!PageHuge(page))
  

•           wait_on_page_writeback(page);
    if (PageHWPoison(page)) {
            unlock_page(page);
            put_page(page);
            pr_info("soft offline: %#lx page already poisoned\n", pfn);
            return -EBUSY;
    }
  

•   /*
  

•    * Try to invalidate first. This should work for
  

•    * non dirty unmapped page cache pages.
  

•    */
  

•   ret = invalidate_inode_page(page);
  

•   if (!PageHuge(page))
  

•           /*
  

•            * Try to invalidate first. This should work for
  

•            * non dirty unmapped page cache pages.
  

•            */
  

•           ret = invalidate_inode_page(page);
    unlock_page(page);
  

•   /*
     * RED-PEN would be better to keep it isolated here, but we
     * would need to fix isolation locking first.
     */
  

•   if (ret == 1) {
  

•   if (ret) {
            pr_info("soft_offline: %#lx: invalidated\n", pfn);
  

•           page_handle_poison(page, true);
  

•           page_handle_poison(page, false, true);
  

arm64 build failed on linux-next 20200626 tag

make -sk KBUILD_BUILD_USER=TuxBuild -C/linux -j16 ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- HOSTCC=gcc CC="sccache aarch64-linux-gnu-gcc" O=build Image 79 # 80 ../mm/memory-failure.c: In function ‘__soft_offline_page’: 81 ../mm/memory-failure.c:1827:3: error: implicit declaration of function ‘page_handle_poison’; did you mean ‘page_init_poison’? [-Werror=implicit-function-declaration] 82 1827 | page_handle_poison(page, false, true); 83 | ^~~~~~~~~~~~~~~~~~ 84 | page_init_poison

Thanks for reporting, Naresh, Qian Cai.

page_handle_poison() is now defined in #ifdef CONFIG_HWPOISON_INJECT block, which is not correct because this function is used in non-injection code path. I'd like to move this function out of the block and it affects multiple patches in this series, so maybe I have to update/resend the whole series, but I like to wait for a few days for other reviews, so for quick fix for linux-next I suggest the following one.

Andrew, could you append this diff on top of this series on mmotm?

Thanks, Naoya Horiguchi --- diff --git a/mm/memory-failure.c b/mm/memory-failure.c index e90ddddab397..b49590bc5615 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -78,38 +78,6 @@ EXPORT_SYMBOL_GPL(hwpoison_filter_dev_minor); EXPORT_SYMBOL_GPL(hwpoison_filter_flags_mask); EXPORT_SYMBOL_GPL(hwpoison_filter_flags_value);

-static bool page_handle_poison(struct page *page, bool hugepage_or_freepage, bool release) -{ - if (release) { - put_page(page); - drain_all_pages(page_zone(page)); - } - - if (hugepage_or_freepage) { - /* - * Doing this check for free pages is also fine since dissolve_free_huge_page - * returns 0 for non-hugetlb pages as well. - */ - if (dissolve_free_huge_page(page) || !take_page_off_buddy(page)) - /* - * The hugetlb page can end up being enqueued back into - * the freelists by means of: - * unmap_and_move_huge_page - * putback_active_hugepage - * put_page->free_huge_page - * enqueue_huge_page - * If this happens, we might lose the race against an allocation. - */ - return false; - } - - SetPageHWPoison(page); - page_ref_inc(page); - num_poisoned_pages_inc(); - - return true; -} - static int hwpoison_filter_dev(struct page *p) { struct address_space *mapping; @@ -204,6 +172,38 @@ int hwpoison_filter(struct page *p)

EXPORT_SYMBOL_GPL(hwpoison_filter);

+static bool page_handle_poison(struct page *page, bool hugepage_or_freepage, bool release) +{ + if (release) { + put_page(page); + drain_all_pages(page_zone(page)); + } + + if (hugepage_or_freepage) { + /* + * Doing this check for free pages is also fine since dissolve_free_huge_page + * returns 0 for non-hugetlb pages as well. + */ + if (dissolve_free_huge_page(page) || !take_page_off_buddy(page)) + /* + * The hugetlb page can end up being enqueued back into + * the freelists by means of: + * unmap_and_move_huge_page + * putback_active_hugepage + * put_page->free_huge_page + * enqueue_huge_page + * If this happens, we might lose the race against an allocation. + */ + return false; + } + + SetPageHWPoison(page); + page_ref_inc(page); + num_poisoned_pages_inc(); + + return true; +} + /* * Kill all processes that have a poisoned page mapped and then isolate * the page.