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Wed, 21 Aug 2024 15:40:50 +0800 Subject: Re: [PATCH v2 2/5] mm: memory-failure: add unmap_posioned_folio() To: Kefeng Wang , 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: Miaohe Lin Message-ID: Date: Wed, 21 Aug 2024 15:40:49 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <20240817084941.2375713-3-wangkefeng.wang@huawei.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.173.127.72] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To kwepemd200019.china.huawei.com (7.221.188.193) X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: AA1321A0009 X-Stat-Signature: gphb3qefir4cumoq5ciqkzqd7q7uefd3 X-Rspam-User: X-HE-Tag: 1724226054-409376 X-HE-Meta: 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 jXX22U92 ADeGad+FGdMzHnEAs6qVS+WR46syA5q+4+Ak5+Ijbpi+iDvHuy53KYHoNpI1Fq5IFbpJz5WKHY+2QxkCae9g+myXFdzFWdCdvTQ05KMbPSjq4tNkEP6unltritT8NmZkHhu74X9928Dqd2jVegRBPylWFFvzCVi7Qlq0YNvaMHq6gWPloDDiwNjSIwR756oCbvoybQCwr2suUIlidVZF+cfFdK4wsffHOtrZUKFIgV4CoVqv+/CL2DZV7jQvzyNWyIoqmdm++Ptee1xmV09RM+rYtPAICaSc+5FCWWOjtuYgukP4= 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 2024/8/17 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/ :) > +{ > + 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. > +} > + > /* > * 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. Thanks. .