Commit ab475510 authored by Jiri Bohac's avatar Jiri Bohac Committed by Andrew Morton
Browse files

kdump: implement reserve_crashkernel_cma 

reserve_crashkernel_cma() reserves CMA ranges for the crash kernel.  If
allocating the requested size fails, try to reserve in smaller blocks.

Store the reserved ranges in the crashk_cma_ranges array and the number of
ranges in crashk_cma_cnt.

Link: https://lkml.kernel.org/r/aEqpBwOy_ekm0gw9@dwarf.suse.cz


Signed-off-by: default avatarJiri Bohac <jbohac@suse.cz>
Cc: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Donald Dutile <ddutile@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Philipp Rudo <prudo@redhat.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Tao Liu <ltao@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 35c18f29

include/linux/crash_reserve.h

+12 −0
Original line number Diff line number Diff line
@@ -13,12 +13,24 @@ 
 */

extern struct resource crashk_res;

extern struct resource crashk_low_res;

extern struct range crashk_cma_ranges[];

#if defined(CONFIG_CMA) && defined(CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION)

#define CRASHKERNEL_CMA

#define CRASHKERNEL_CMA_RANGES_MAX 4

extern int crashk_cma_cnt;

#else

#define crashk_cma_cnt 0

#define CRASHKERNEL_CMA_RANGES_MAX 0

#endif





int __init parse_crashkernel(char *cmdline, unsigned long long system_ram,

		unsigned long long *crash_size, unsigned long long *crash_base,

		unsigned long long *low_size, unsigned long long *cma_size,

		bool *high);



void __init reserve_crashkernel_cma(unsigned long long cma_size);



#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION

#ifndef DEFAULT_CRASH_KERNEL_LOW_SIZE

#define DEFAULT_CRASH_KERNEL_LOW_SIZE	(128UL << 20)

kernel/crash_reserve.c

+52 −0
Original line number Diff line number Diff line
@@ -14,6 +14,8 @@ 
#include <linux/cpuhotplug.h>

#include <linux/memblock.h>

#include <linux/kmemleak.h>

#include <linux/cma.h>

#include <linux/crash_reserve.h>



#include <asm/page.h>

#include <asm/sections.h>
@@ -469,6 +471,56 @@ void __init reserve_crashkernel_generic(unsigned long long crash_size, 
#endif

}



struct range crashk_cma_ranges[CRASHKERNEL_CMA_RANGES_MAX];

#ifdef CRASHKERNEL_CMA

int crashk_cma_cnt;

void __init reserve_crashkernel_cma(unsigned long long cma_size)

{

	unsigned long long request_size = roundup(cma_size, PAGE_SIZE);

	unsigned long long reserved_size = 0;



	if (!cma_size)

		return;



	while (cma_size > reserved_size &&

	       crashk_cma_cnt < CRASHKERNEL_CMA_RANGES_MAX) {



		struct cma *res;



		if (cma_declare_contiguous(0, request_size, 0, 0, 0, false,

				       "crashkernel", &res)) {

			/* reservation failed, try half-sized blocks */

			if (request_size <= PAGE_SIZE)

				break;



			request_size = roundup(request_size / 2, PAGE_SIZE);

			continue;

		}



		crashk_cma_ranges[crashk_cma_cnt].start = cma_get_base(res);

		crashk_cma_ranges[crashk_cma_cnt].end =

			crashk_cma_ranges[crashk_cma_cnt].start +

			cma_get_size(res) - 1;

		++crashk_cma_cnt;

		reserved_size += request_size;

	}



	if (cma_size > reserved_size)

		pr_warn("crashkernel CMA reservation failed: %lld MB requested, %lld MB reserved in %d ranges\n",

			cma_size >> 20, reserved_size >> 20, crashk_cma_cnt);

	else

		pr_info("crashkernel CMA reserved: %lld MB in %d ranges\n",

			reserved_size >> 20, crashk_cma_cnt);

}



#else /* CRASHKERNEL_CMA */

void __init reserve_crashkernel_cma(unsigned long long cma_size)

{

	if (cma_size)

		pr_warn("crashkernel CMA reservation not supported\n");

}

#endif



#ifndef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY

static __init int insert_crashkernel_resources(void)

{