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Commit 3f74e0bd authored by Sudarshan Rajagopalan's avatar Sudarshan Rajagopalan Committed by Gerrit - the friendly Code Review server
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arm64: Override memory limit set by boot parameter 



To guarantee successful hot-plugging of memory blocks, these blocks
should belong to ZONE_MOVABLE which has migratable pages. Linux kernel
during boot initializes all the available memory blocks to ZONE_DMA and
ZONE_NORMAL. Hence, boot the system with less memory whose percentage
is given by mem-offline DT property 'mem-percent' and override any memory
limit imposed by kernel boot params and let mem-offline driver initialize
the remaining with ZONE_MOVABLE. The memory blocks in this zone are
applicable for memory offlining.

Change-Id: Ia7b804522fe9425101ee83d1ee354ed09483df13
Signed-off-by: default avatarSudarshan Rajagopalan <sudaraja@codeaurora.org>
parent ad35f441

arch/arm64/mm/init.c

+48 −0
Original line number Diff line number Diff line
@@ -40,6 +40,8 @@ 
#include <linux/mm.h>

#include <linux/kexec.h>

#include <linux/crash_dump.h>

#include <linux/memory.h>

#include <linux/libfdt.h>



#include <asm/boot.h>

#include <asm/fixmap.h>
@@ -315,6 +317,51 @@ static void __init arm64_memory_present(void) 
static phys_addr_t memory_limit = (phys_addr_t)ULLONG_MAX;

phys_addr_t bootloader_memory_limit;



#ifdef CONFIG_OVERRIDE_MEMORY_LIMIT

static void __init update_memory_limit(void)

{

	unsigned long dt_root = of_get_flat_dt_root();

	unsigned long node, mp;

	const char *p;

	unsigned long long ram_sz, sz;

	int ret;



	ram_sz = memblock_end_of_DRAM() - memblock_start_of_DRAM();

	node = of_get_flat_dt_subnode_by_name(dt_root, "mem-offline");

	if (node == -FDT_ERR_NOTFOUND) {

		pr_err("mem-offine node not found in FDT\n");

		return;

	}

	p = of_get_flat_dt_prop(node, "mem-percent", NULL);

	if (!p) {

		pr_err("mem-offine: mem-percent property not found in FDT\n");

		return;

	}



	ret = kstrtoul(p, 10, &mp);

	if (ret) {

		pr_err("mem-offine: kstrtoul failed\n");

		return;

	}



	if (mp > 100) {

		pr_err("mem-offine: Invalid mem-percent DT property\n");

		return;

	}

	sz = ram_sz - ((ram_sz * mp) / 100);

	memory_limit = (phys_addr_t)sz;

	memory_limit = ALIGN(memory_limit, MIN_MEMORY_BLOCK_SIZE);



	pr_notice("Memory limit set/overridden to %lldMB\n",

							memory_limit >> 20);

}

#else

static void __init update_memory_limit(void)

{



}

#endif



/*

 * Limit the memory size that was specified via FDT.

 */
@@ -396,6 +443,7 @@ void __init arm64_memblock_init(void) 
		memblock_remove(0, memstart_addr);

	}



	update_memory_limit();

	/*

	 * Save bootloader imposed memory limit before we overwirte

	 * memblock.

drivers/soc/qcom/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -12,6 +12,16 @@ config QCOM_MEM_OFFLINE 
	  helps reduce power consumption during idle mode of the system.

	  If unsure, say N



config OVERRIDE_MEMORY_LIMIT

	bool "Override memory limit set by the kernel boot parameter"

	depends on QCOM_MEM_OFFLINE

	help

	  Override any memory limit set by the kernel boot parameter with

	  limit set by mem-offline dt entry so that memory offline framework

	  can initialize remaining memory with movable pages for memory

	  hot-plugging.

	  If unsure, say N



config QCOM_CPUSS_DUMP

	bool "CPU Subsystem Dumping support"

	help