From 69afade72a3e13e96a065f757891d384d466123f Mon Sep 17 00:00:00 2001 From: Jiang Liu Date: Mon, 29 Apr 2013 15:06:21 -0700 Subject: [PATCH] mm: introduce common help functions to deal with reserved/managed pages The original goal of this patchset is to fix the bug reported by https://bugzilla.kernel.org/show_bug.cgi?id=53501 Now it has also been expanded to reduce common code used by memory initializion. This is the first part, which applies to v3.9-rc1. It introduces following common helper functions to simplify free_initmem() and free_initrd_mem() on different architectures: adjust_managed_page_count(): will be used to adjust totalram_pages, totalhigh_pages, zone->managed_pages when reserving/unresering a page. __free_reserved_page(): free a reserved page into the buddy system without adjusting page statistics info free_reserved_page(): free a reserved page into the buddy system and adjust page statistics info mark_page_reserved(): mark a page as reserved and adjust page statistics info free_reserved_area(): free a continous ranges of pages by calling free_reserved_page() free_initmem_default(): default method to free __init pages. We have only tested these patchset on x86 platforms, and have done basic compliation tests using cross-compilers from ftp.kernel.org. That means some code may not pass compilation on some architectures. So any help to test this patchset are welcomed! There are several other parts still under development: Part2: introduce free_highmem_page() to simplify freeing highmem pages Part3: refine code to manage totalram_pages, totalhigh_pages and zone->managed_pages Part4: introduce helper functions to simplify mem_init() and remove the global variable num_physpages. This patch: Code to deal with reserved/managed pages are duplicated by many architectures, so introduce common help functions to reduce duplicated code. These common help functions will also be used to concentrate code to modify totalram_pages and zone->managed_pages, which makes the code much more clear. Signed-off-by: Jiang Liu Acked-by: Geert Uytterhoeven Cc: "H. Peter Anvin" Cc: "James E.J. Bottomley" Cc: Anatolij Gustschin Cc: Aurelien Jacquiot Cc: Benjamin Herrenschmidt Cc: Catalin Marinas Cc: Chen Liqin Cc: Chris Zankel Cc: David Howells Cc: David S. Miller Cc: Eric Biederman Cc: Fenghua Yu Cc: Guan Xuetao Cc: Haavard Skinnemoen Cc: Hans-Christian Egtvedt Cc: Heiko Carstens Cc: Helge Deller Cc: Hirokazu Takata Cc: Ingo Molnar Cc: Ivan Kokshaysky Cc: James Hogan Cc: Jeff Dike Cc: Jiang Liu Cc: Jiang Liu Cc: Jonas Bonn Cc: Koichi Yasutake Cc: Lennox Wu Cc: Mark Salter Cc: Martin Schwidefsky Cc: Matt Turner Cc: Max Filippov Cc: Michal Simek Cc: Mikael Starvik Cc: Mike Frysinger Cc: Paul Mackerras Cc: Paul Mundt Cc: Ralf Baechle Cc: Richard Henderson Cc: Russell King Cc: Sam Ravnborg Cc: Thomas Gleixner Cc: Tony Luck Cc: Vineet Gupta Cc: Will Deacon Cc: Yoshinori Sato Cc: Zhang Yanfei Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mm.h | 48 ++++++++++++++++++++++++++++++++++++++++++++++ mm/page_alloc.c | 20 +++++++++++++++++++ 2 files changed, 68 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index f3c7b1f9d1d8..d064c73c925e 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1295,6 +1295,54 @@ extern void free_area_init_node(int nid, unsigned long * zones_size, unsigned long zone_start_pfn, unsigned long *zholes_size); extern void free_initmem(void); +/* + * Free reserved pages within range [PAGE_ALIGN(start), end & PAGE_MASK) + * into the buddy system. The freed pages will be poisoned with pattern + * "poison" if it's non-zero. + * Return pages freed into the buddy system. + */ +extern unsigned long free_reserved_area(unsigned long start, unsigned long end, + int poison, char *s); + +static inline void adjust_managed_page_count(struct page *page, long count) +{ + totalram_pages += count; +} + +/* Free the reserved page into the buddy system, so it gets managed. */ +static inline void __free_reserved_page(struct page *page) +{ + ClearPageReserved(page); + init_page_count(page); + __free_page(page); +} + +static inline void free_reserved_page(struct page *page) +{ + __free_reserved_page(page); + adjust_managed_page_count(page, 1); +} + +static inline void mark_page_reserved(struct page *page) +{ + SetPageReserved(page); + adjust_managed_page_count(page, -1); +} + +/* + * Default method to free all the __init memory into the buddy system. + * The freed pages will be poisoned with pattern "poison" if it is + * non-zero. Return pages freed into the buddy system. + */ +static inline unsigned long free_initmem_default(int poison) +{ + extern char __init_begin[], __init_end[]; + + return free_reserved_area(PAGE_ALIGN((unsigned long)&__init_begin) , + ((unsigned long)&__init_end) & PAGE_MASK, + poison, "unused kernel"); +} + #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP /* * With CONFIG_HAVE_MEMBLOCK_NODE_MAP set, an architecture may initialise its diff --git a/mm/page_alloc.c b/mm/page_alloc.c index da7a2fe7332e..5c660f5ba3d3 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5121,6 +5121,26 @@ early_param("movablecore", cmdline_parse_movablecore); #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */ +unsigned long free_reserved_area(unsigned long start, unsigned long end, + int poison, char *s) +{ + unsigned long pages, pos; + + pos = start = PAGE_ALIGN(start); + end &= PAGE_MASK; + for (pages = 0; pos < end; pos += PAGE_SIZE, pages++) { + if (poison) + memset((void *)pos, poison, PAGE_SIZE); + free_reserved_page(virt_to_page(pos)); + } + + if (pages && s) + pr_info("Freeing %s memory: %ldK (%lx - %lx)\n", + s, pages << (PAGE_SHIFT - 10), start, end); + + return pages; +} + /** * set_dma_reserve - set the specified number of pages reserved in the first zone * @new_dma_reserve: The number of pages to mark reserved -- GitLab