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Commit 85975387 authored by Hari Bathini's avatar Hari Bathini Committed by Michael Ellerman
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powerpc/fadump: Do not use hugepages when fadump is active 



FADump capture kernel boots in restricted memory environment preserving
the context of previous kernel to save vmcore. Supporting hugepages in
such environment makes things unnecessarily complicated, as hugepages
need memory set aside for them. This means most of the capture kernel's
memory is used in supporting hugepages. In most cases, this results in
out-of-memory issues while booting FADump capture kernel. But hugepages
are not of much use in capture kernel whose only job is to save vmcore.
So, disabling hugepages support, when fadump is active, is a reliable
solution for the out of memory issues. Introducing a flag variable to
disable HugeTLB support when fadump is active.

Signed-off-by: default avatarHari Bathini <hbathini@linux.vnet.ibm.com>
Reviewed-by: default avatarMahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent b71a693d

arch/powerpc/include/asm/page.h

+1 −0
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ 


#ifndef __ASSEMBLY__

#ifdef CONFIG_HUGETLB_PAGE

extern bool hugetlb_disabled;

extern unsigned int HPAGE_SHIFT;

#else

#define HPAGE_SHIFT PAGE_SHIFT

arch/powerpc/kernel/fadump.c

+8 −0
Original line number Diff line number Diff line
@@ -402,6 +402,14 @@ int __init fadump_reserve_mem(void) 
	if (fw_dump.dump_active) {

		pr_info("Firmware-assisted dump is active.\n");



#ifdef CONFIG_HUGETLB_PAGE

		/*

		 * FADump capture kernel doesn't care much about hugepages.

		 * In fact, handling hugepages in capture kernel is asking for

		 * trouble. So, disable HugeTLB support when fadump is active.

		 */

		hugetlb_disabled = true;

#endif

		/*

		 * If last boot has crashed then reserve all the memory

		 * above boot_memory_size so that we don't touch it until

arch/powerpc/mm/hash_utils_64.c

+4 −2
Original line number Diff line number Diff line
@@ -572,8 +572,10 @@ static void __init htab_scan_page_sizes(void) 
	}



#ifdef CONFIG_HUGETLB_PAGE

	if (!hugetlb_disabled) {

		/* Reserve 16G huge page memory sections for huge pages */

		of_scan_flat_dt(htab_dt_scan_hugepage_blocks, NULL);

	}

#endif /* CONFIG_HUGETLB_PAGE */

}

arch/powerpc/mm/hugetlbpage.c

+7 −0
Original line number Diff line number Diff line
@@ -35,6 +35,8 @@ 
#define PAGE_SHIFT_16M	24

#define PAGE_SHIFT_16G	34



bool hugetlb_disabled = false;



unsigned int HPAGE_SHIFT;

EXPORT_SYMBOL(HPAGE_SHIFT);
@@ -651,6 +653,11 @@ static int __init hugetlbpage_init(void) 
{

	int psize;



	if (hugetlb_disabled) {

		pr_info("HugeTLB support is disabled!\n");

		return 0;

	}



#if !defined(CONFIG_PPC_FSL_BOOK3E) && !defined(CONFIG_PPC_8xx)

	if (!radix_enabled() && !mmu_has_feature(MMU_FTR_16M_PAGE))

		return -ENODEV;