From f6f34b4387d9e18304451a131b35d7c4f27a0b5a Mon Sep 17 00:00:00 2001 From: Srikar Dronamraju Date: Fri, 7 Oct 2016 16:59:15 -0700 Subject: mm: introduce arch_reserved_kernel_pages() Currently arch specific code can reserve memory blocks but alloc_large_system_hash() may not take it into consideration when sizing the hashes. This can lead to bigger hash than required and lead to no available memory for other purposes. This is specifically true for systems with CONFIG_DEFERRED_STRUCT_PAGE_INIT enabled. One approach to solve this problem would be to walk through the memblock regions and calculate the available memory and base the size of hash system on the available memory. The other approach would be to depend on the architecture to provide the number of pages that are reserved. This change provides hooks to allow the architecture to provide the required info. Link: http://lkml.kernel.org/r/1472476010-4709-2-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Srikar Dronamraju Suggested-by: Mel Gorman Cc: Vlastimil Babka Cc: Michal Hocko Cc: Michael Ellerman Cc: Mahesh Salgaonkar Cc: Hari Bathini Cc: Dave Hansen Cc: Balbir Singh Cc: Benjamin Herrenschmidt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mm.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux/mm.h') diff --git a/include/linux/mm.h b/include/linux/mm.h index 0a063b4e4456..046077b4209d 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1924,6 +1924,9 @@ extern void show_mem(unsigned int flags); extern long si_mem_available(void); extern void si_meminfo(struct sysinfo * val); extern void si_meminfo_node(struct sysinfo *val, int nid); +#ifdef __HAVE_ARCH_RESERVED_KERNEL_PAGES +extern unsigned long arch_reserved_kernel_pages(void); +#endif extern __printf(3, 4) void warn_alloc_failed(gfp_t gfp_mask, unsigned int order, -- cgit v1.2.3