Commit c37d1a01 authored by Usama Arif's avatar Usama Arif Committed by Jinjiang Tu
Browse files

memblock: introduce MEMBLOCK_RSRV_NOINIT flag 

mainline inclusion
from mainline-v6.7-rc1
commit 77e6c43e137c130138c3fbadc847351a83c4befe
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8JXRC
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=77e6c43e137c130138c3fbadc847351a83c4befe

-------------------------------------------

For reserved memory regions marked with this flag, reserve_bootmem_region
is not called during memmap_init_reserved_pages.  This can be used to
avoid struct page initialization for regions which won't need them, for
e.g.  hugepages with Hugepage Vmemmap Optimization enabled.

Link: https://lkml.kernel.org/r/20230913105401.519709-4-usama.arif@bytedance.com


Signed-off-by: default avatarUsama Arif <usama.arif@bytedance.com>
Acked-by: default avatarMuchun Song <songmuchun@bytedance.com>
Reviewed-by: default avatarMike Rapoport (IBM) <rppt@kernel.org>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Punit Agrawal <punit.agrawal@bytedance.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarJinjiang Tu <tujinjiang@huawei.com>
parent ec2f3919

include/linux/memblock.h

+9 −0
Original line number Diff line number Diff line
@@ -40,6 +40,8 @@ extern unsigned long long max_possible_pfn; 
 * via a driver, and never indicated in the firmware-provided memory map as

 * system RAM. This corresponds to IORESOURCE_SYSRAM_DRIVER_MANAGED in the

 * kernel resource tree.

 * @MEMBLOCK_RSRV_NOINIT: memory region for which struct pages are

 * not initialized (only for reserved regions).

 */

enum memblock_flags {

	MEMBLOCK_NONE		= 0x0,	/* No special request */
@@ -47,6 +49,7 @@ enum memblock_flags { 
	MEMBLOCK_MIRROR		= 0x2,	/* mirrored region */

	MEMBLOCK_NOMAP		= 0x4,	/* don't add to kernel direct mapping */

	MEMBLOCK_DRIVER_MANAGED = 0x8,	/* always detected via a driver */

	MEMBLOCK_RSRV_NOINIT	= 0x10,	/* don't initialize struct pages */

};



/**
@@ -125,6 +128,7 @@ int memblock_clear_hotplug(phys_addr_t base, phys_addr_t size); 
int memblock_mark_mirror(phys_addr_t base, phys_addr_t size);

int memblock_mark_nomap(phys_addr_t base, phys_addr_t size);

int memblock_clear_nomap(phys_addr_t base, phys_addr_t size);

int memblock_reserved_mark_noinit(phys_addr_t base, phys_addr_t size);



void memblock_free_all(void);

void memblock_free(void *ptr, size_t size);
@@ -259,6 +263,11 @@ static inline bool memblock_is_nomap(struct memblock_region *m) 
	return m->flags & MEMBLOCK_NOMAP;

}



static inline bool memblock_is_reserved_noinit(struct memblock_region *m)

{

	return m->flags & MEMBLOCK_RSRV_NOINIT;

}



static inline bool memblock_is_driver_managed(struct memblock_region *m)

{

	return m->flags & MEMBLOCK_DRIVER_MANAGED;

mm/memblock.c

+28 −5
Original line number Diff line number Diff line
@@ -997,6 +997,24 @@ int __init_memblock memblock_clear_nomap(phys_addr_t base, phys_addr_t size) 
	return memblock_setclr_flag(&memblock.memory, base, size, 0, MEMBLOCK_NOMAP);

}



/**

 * memblock_reserved_mark_noinit - Mark a reserved memory region with flag

 * MEMBLOCK_RSRV_NOINIT which results in the struct pages not being initialized

 * for this region.

 * @base: the base phys addr of the region

 * @size: the size of the region

 *

 * struct pages will not be initialized for reserved memory regions marked with

 * %MEMBLOCK_RSRV_NOINIT.

 *

 * Return: 0 on success, -errno on failure.

 */

int __init_memblock memblock_reserved_mark_noinit(phys_addr_t base, phys_addr_t size)

{

	return memblock_setclr_flag(&memblock.reserved, base, size, 1,

				    MEMBLOCK_RSRV_NOINIT);

}



static bool should_skip_region(struct memblock_type *type,

			       struct memblock_region *m,

			       int nid, int flags)
@@ -2113,8 +2131,12 @@ static void __init memmap_init_reserved_pages(void) 
		memblock_set_node(start, end, &memblock.reserved, nid);

	}



	/* initialize struct pages for the reserved regions */

	/*

	 * initialize struct pages for reserved regions that don't have

	 * the MEMBLOCK_RSRV_NOINIT flag set

	 */

	for_each_reserved_mem_region(region) {

		if (!memblock_is_reserved_noinit(region)) {

			nid = memblock_get_region_node(region);

			start = region->base;

			end = start + region->size;
@@ -2122,6 +2144,7 @@ static void __init memmap_init_reserved_pages(void) 
			reserve_bootmem_region(start, end, nid);

		}

	}

}



static unsigned long __init free_low_memory_core_early(void)

{