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Wed, 21 Aug 2024 16:54:58 +0800 Message-ID: <6ad159e0-7fa6-4ca9-a2d1-9f65f9d7a3cb@huawei.com> Date: Wed, 21 Aug 2024 16:54:58 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 2/5] mm: memory-failure: add unmap_posioned_folio() Content-Language: en-US To: Miaohe Lin , Andrew Morton CC: David Hildenbrand , Oscar Salvador , Naoya Horiguchi , References: <20240817084941.2375713-1-wangkefeng.wang@huawei.com> <20240817084941.2375713-3-wangkefeng.wang@huawei.com> From: Kefeng Wang In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.177.243] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggpemf100008.china.huawei.com (7.185.36.138) X-Stat-Signature: p93jcak5okk3zgfg9oty76y3yq8ii9w5 X-Rspamd-Queue-Id: CF8E5180016 X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1724230503-964688 X-HE-Meta: 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 n3kd4UuR 0dcFQWI1cMFv9jjO9M7sPNjjQQObec8JO6hikZKCB7b1eBnSfpNiMtsUNAhIddE0QSKYAzggVQzzBWjN+myI8rpAZE6+v/gQ1US6Qa26BobXMStonyC6vbkOEVrN4Gp/amZ1LLyELqpv0xVZgAym9us+snxZ7X3oKPgwb6jUMuYFjCaHh9Lo1g26r+WbgRufee1b41Lm6YAHxn0lCEFE8x5UkS5Vre7mliFCeLMTS857UXkJiq+K2qY1hU6hduDIiMxvfFcBgXxf2io5qjGkiJUoYA4WXFKa3VyZgoRRr0S9pkjfOl6yyjnHVzZKIXi+JQUqtwUaUmxzclv8= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2024/8/21 15:40, Miaohe Lin wrote: > On 2024/8/17 16:49, Kefeng Wang wrote: >> Add unmap_posioned_folio() helper which will be reused by >> do_migrate_range() from memory hotplug soon. >> >> Acked-by: David Hildenbrand >> Signed-off-by: Kefeng Wang >> --- >> mm/internal.h | 9 +++++++++ >> mm/memory-failure.c | 43 ++++++++++++++++++++++++++----------------- >> 2 files changed, 35 insertions(+), 17 deletions(-) >> >> diff --git a/mm/internal.h b/mm/internal.h >> index d7aac802efa5..74490b8ac63d 100644 >> --- a/mm/internal.h >> +++ b/mm/internal.h >> @@ -1045,6 +1045,8 @@ static inline int find_next_best_node(int node, nodemask_t *used_node_mask) >> /* >> * mm/memory-failure.c >> */ >> +#ifdef CONFIG_MEMORY_FAILURE >> +int unmap_posioned_folio(struct folio *folio, enum ttu_flags ttu); >> void shake_folio(struct folio *folio); >> extern int hwpoison_filter(struct page *p); >> >> @@ -1065,6 +1067,13 @@ void add_to_kill_ksm(struct task_struct *tsk, struct page *p, >> unsigned long ksm_addr); >> unsigned long page_mapped_in_vma(struct page *page, struct vm_area_struct *vma); >> >> +#else >> +static inline int unmap_posioned_folio(struct folio *folio, enum ttu_flags ttu) >> +{ >> + return 0; >> +} >> +#endif >> + >> extern unsigned long __must_check vm_mmap_pgoff(struct file *, unsigned long, >> unsigned long, unsigned long, >> unsigned long, unsigned long); >> diff --git a/mm/memory-failure.c b/mm/memory-failure.c >> index 353254537b54..93848330de1f 100644 >> --- a/mm/memory-failure.c >> +++ b/mm/memory-failure.c >> @@ -1554,6 +1554,30 @@ static int get_hwpoison_page(struct page *p, unsigned long flags) >> return ret; >> } >> >> +int unmap_posioned_folio(struct folio *folio, enum ttu_flags ttu) > > Should it be unmap_poisoned_folio ? i.e. s/posioned/poisoned/ :) Oh, my bad. > >> +{ >> + if (folio_test_hugetlb(folio) && !folio_test_anon(folio)) { >> + struct address_space *mapping; >> + /* >> + * For hugetlb pages in shared mappings, try_to_unmap >> + * could potentially call huge_pmd_unshare. Because of >> + * this, take semaphore in write mode here and set >> + * TTU_RMAP_LOCKED to indicate we have taken the lock >> + * at this higher level. >> + */ >> + mapping = hugetlb_folio_mapping_lock_write(folio); >> + if (!mapping) >> + return -EAGAIN; >> + >> + try_to_unmap(folio, ttu|TTU_RMAP_LOCKED); >> + i_mmap_unlock_write(mapping); >> + } else { >> + try_to_unmap(folio, ttu); >> + } >> + >> + return 0; > > It seems return value is not really needed? We will check folio_mapped below. It is just to keep the same as before, but > >> +} >> + >> /* >> * Do all that is necessary to remove user space mappings. Unmap >> * the pages and send SIGBUS to the processes if the data was dirty. >> @@ -1615,23 +1639,8 @@ static bool hwpoison_user_mappings(struct folio *folio, struct page *p, >> */ >> collect_procs(folio, p, &tokill, flags & MF_ACTION_REQUIRED); >> >> - if (folio_test_hugetlb(folio) && !folio_test_anon(folio)) { >> - /* >> - * For hugetlb pages in shared mappings, try_to_unmap >> - * could potentially call huge_pmd_unshare. Because of >> - * this, take semaphore in write mode here and set >> - * TTU_RMAP_LOCKED to indicate we have taken the lock >> - * at this higher level. >> - */ >> - mapping = hugetlb_folio_mapping_lock_write(folio); >> - if (mapping) { >> - try_to_unmap(folio, ttu|TTU_RMAP_LOCKED); >> - i_mmap_unlock_write(mapping); >> - } else >> - pr_info("%#lx: could not lock mapping for mapped huge page\n", pfn); >> - } else { >> - try_to_unmap(folio, ttu); >> - } >> + if (unmap_posioned_folio(folio, ttu)) >> + pr_info("%#lx: could not lock mapping for mapped huge page\n", pfn); > > It might be better to pr_info inside the unmap_posioned_folio? unmap_posioned_folio might fail due > to other reasons in the future anyway. think it again, we have another check and print when recheck folio_mapped(), so killing the return value and this print for hugepage is better, and in memory-hotplug, we don't pr_warn for this case. I will remove return and this print if no objection. > > Thanks. > .