mm: don't do zero_resv_unavail if memmap is not allocated (d1b47a7c) · Commits · 戴 / test

Moving zero_resv_unavail before memmap_init_zone(), caused a regression on x86-32. The cause is that we access struct pages before they are allocated when CONFIG_FLAT_NODE_MEM_MAP is used. free_area_init_nodes() zero_resv_unavail() mm_zero_struct_page(pfn_to_page(pfn)); <- struct page is not alloced free_area_init_node() if CONFIG_FLAT_NODE_MEM_MAP alloc_node_mem_map() memblock_virt_alloc_node_nopanic() <- struct page alloced here On the other hand memblock_virt_alloc_node_nopanic() zeroes all the memory that it returns, so we do not need to do zero_resv_unavail() here. Fixes: ("mm: zero unavailable pages before memmap init") Signed-off-by:

Pavel Tatashin <pasha.tatashin@oracle.com> Tested-by:

Matt Hart <matt@mattface.org> Acked-by:

Michal Hocko <mhocko@suse.com> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

include/linux/mm.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -2132,7 +2132,7 @@ extern int __meminit __early_pfn_to_nid(unsigned long pfn,
		struct mminit_pfnnid_cache *state);
		#endif

		#ifdef CONFIG_HAVE_MEMBLOCK
		#if defined(CONFIG_HAVE_MEMBLOCK) && !defined(CONFIG_FLAT_NODE_MEM_MAP)
		void zero_resv_unavail(void);
		#else
		static inline void zero_resv_unavail(void) {}

mm/page_alloc.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -6383,7 +6383,7 @@ void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
		free_area_init_core(pgdat);
		}

		#ifdef CONFIG_HAVE_MEMBLOCK
		#if defined(CONFIG_HAVE_MEMBLOCK) && !defined(CONFIG_FLAT_NODE_MEM_MAP)
		/*
		* Only struct pages that are backed by physical memory are zeroed and
		* initialized by going through __init_single_page(). But, there are some
		@@ -6421,7 +6421,7 @@ void __paginginit zero_resv_unavail(void)
		if (pgcnt)
		pr_info("Reserved but unavailable: %lld pages", pgcnt);
		}
		#endif /* CONFIG_HAVE_MEMBLOCK */
		#endif /* CONFIG_HAVE_MEMBLOCK && !CONFIG_FLAT_NODE_MEM_MAP */

		#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP

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