Messages in this thread | | | Date | Tue, 21 Nov 2023 15:42:43 +0100 | Subject | Re: [PATCH 0/8] implement "memmap on memory" feature on s390 | From | David Hildenbrand <> |
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On 21.11.23 14:21, Sumanth Korikkar wrote: > On Tue, Nov 21, 2023 at 02:13:22PM +0100, Sumanth Korikkar wrote: >> Approach 2: >> =========== >> Shouldnt kasan zero shadow mapping performed first before >> accessing/initializing memmap via page_init_poisining()? If that is >> true, then it is a problem for all architectures and should could be >> fixed like: >> >> >> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c >> index 7a5fc89a8652..eb3975740537 100644 >> --- a/mm/memory_hotplug.c >> +++ b/mm/memory_hotplug.c >> @@ -1093,6 +1093,7 @@ int mhp_init_memmap_on_memory(unsigned long pfn, unsigned long nr_pages, >> if (ret) >> return ret; >> >> + page_init_poison(pfn_to_page(pfn), sizeof(struct page) * nr_pages); >> move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_UNMOVABLE); >> >> for (i = 0; i < nr_pages; i++) >> diff --git a/mm/sparse.c b/mm/sparse.c >> index 77d91e565045..4ddf53f52075 100644 >> --- a/mm/sparse.c >> +++ b/mm/sparse.c >> @@ -906,8 +906,11 @@ int __meminit sparse_add_section(int nid, unsigned long start_pfn, >> /* >> * Poison uninitialized struct pages in order to catch invalid flags >> * combinations. >> + * For altmap, do this later when onlining the memory, as it might >> + * not be accessible at this point. >> */ >> - page_init_poison(memmap, sizeof(struct page) * nr_pages); >> + if (!altmap) >> + page_init_poison(memmap, sizeof(struct page) * nr_pages); >> >> ms = __nr_to_section(section_nr); >> set_section_nid(section_nr, nid); >> >> >> >> Also, if this approach is taken, should page_init_poison() be performed >> with cond_resched() as mentioned in commit d33695b16a9f >> ("mm/memory_hotplug: poison memmap in remove_pfn_range_from_zone()") ? > > Sorry, wrong commit id. > > should page_init_poison() be performed with cond_resched() as mentioned in > Commit b7e3debdd040 ("mm/memory_hotplug.c: fix false softlockup > during pfn range removal") ?
I think people are currently looking into removing all that cond_resched():
https://lore.kernel.org/all/20231107230822.371443-29-ankur.a.arora@oracle.com/T/#mda52da685a142bec9607625386b0b660e5470abe -- Cheers,
David / dhildenb
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