Commit cd1a72f5 authored by Ma Wupeng's avatar Ma Wupeng Committed by Wupeng Ma
Browse files

mm: mem_reliable: Introduce fallback mechanism for memory reliable 

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8USBA


CVE: NA

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

Introduce fallback mechanism for memory reliable. memory allocation will
fallback to non-mirrored region if zone's low watermark is reached and
kswapd will be awakened at this time.

This mechanism is enabled by default and can be disabled by adding
"reliable_debug=F" to the kernel parameters. This mechanism rely on
CONFIG_MEMORY_RELIABLE and need "kernelcore=reliable" in the kernel
parameters.

Signed-off-by: default avatarMa Wupeng <mawupeng1@huawei.com>
parent 200321e8

Documentation/admin-guide/kernel-parameters.txt

+3 −1
Original line number Diff line number Diff line
@@ -5519,11 +5519,13 @@ 
			See Documentation/admin-guide/cgroup-v1/cpusets.rst.



	reliable_debug=	[ARM64]

			Format: [P][,S]

			Format: [P][,S][,F]

			Only works with CONFIG_MEMORY_RELIABLE and

			"kernelcore=reliable" is configured.

			P: Page cache does not use the reliable memory.

			S: The shmem does not use the reliable memory.

			F: User memory allocation(special user task, tmpfs) will

			not allocate memory from non-mirrored region if failed.



	reserve=	[KNL,BUGS] Force kernel to ignore I/O ports or memory

			Format: <base1>,<size1>[,<base2>,<size2>,...]

include/linux/mem_reliable.h

+10 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ DECLARE_STATIC_KEY_FALSE(mem_reliable); 
extern bool reliable_enabled;

extern struct file_operations proc_reliable_operations;

extern bool shmem_reliable;

extern bool reliable_allow_fallback;

extern bool pagecache_reliable;

extern struct percpu_counter pagecache_reliable_pages;

extern struct percpu_counter anon_reliable_pages;
@@ -91,6 +92,11 @@ static inline bool skip_non_mirrored_zone(gfp_t gfp, struct zoneref *z) 
	return false;

}



static inline bool reliable_allow_fb_enabled(void)

{

	return reliable_allow_fallback;

}



static inline bool mem_reliable_shmem_limit_check(void)

{

	return percpu_counter_read_positive(&shmem_reliable_pages) <
@@ -116,6 +122,9 @@ static inline bool shmem_prepare_alloc(gfp_t *gfp_mask) 
		return true;

	}



	if (reliable_allow_fb_enabled())

		return true;



	return false;

}
@@ -207,6 +216,7 @@ static inline void mem_reliable_out_of_memory(gfp_t gfp_mask, 
					      unsigned int order,

					      int preferred_nid,

					      nodemask_t *nodemask) {}

static inline bool reliable_allow_fb_enabled(void) { return false; }

#endif



#endif

mm/mem_reliable.c

+5 −0
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ unsigned long pagecache_reliable_limit = ULONG_MAX; 
/* reliable user limit for user tasks with reliable flag */

unsigned long task_reliable_limit = ULONG_MAX;

unsigned long shmem_reliable_limit = ULONG_MAX;

bool reliable_allow_fallback __read_mostly = true;



bool mem_reliable_counter_initialized(void)

{
@@ -301,6 +302,10 @@ static int __init setup_reliable_debug(char *str) 
			shmem_reliable = false;

			pr_info("disable shmem use reliable memory\n");

			break;

		case 'F':

			reliable_allow_fallback = false;

			pr_info("disable memory reliable fallback\n");

			break;

		default:

			pr_err("reliable_debug option '%c' unknown. skipped\n",

			       *str);

mm/page_alloc.c

+53 −3
Original line number Diff line number Diff line
@@ -4041,6 +4041,52 @@ check_retry_cpuset(int cpuset_mems_cookie, struct alloc_context *ac) 
	return false;

}



#ifdef CONFIG_MEMORY_RELIABLE

/*

 * if fallback is enabled, fallback to movable zone if no dma/normal zone

 * found

 */

static inline struct zone *mem_reliable_fallback_zone(gfp_t gfp_mask,

						      struct alloc_context *ac)

{

	if (!reliable_allow_fb_enabled())

		return NULL;



	if (!(gfp_mask & GFP_RELIABLE))

		return NULL;



	ac->highest_zoneidx = gfp_zone(gfp_mask & ~GFP_RELIABLE);

	ac->preferred_zoneref = first_zones_zonelist(

		ac->zonelist, ac->highest_zoneidx, ac->nodemask);

	return ac->preferred_zoneref->zone;

}



static inline void mem_reliable_fallback_slowpath(gfp_t gfp_mask,

						  struct alloc_context *ac)

{

	if (!reliable_allow_fb_enabled())

		return;



	if (gfp_mask & __GFP_NOFAIL)

		return;



	if ((ac->highest_zoneidx == ZONE_NORMAL) && (gfp_mask & GFP_RELIABLE)) {

		ac->highest_zoneidx = gfp_zone(gfp_mask & ~GFP_RELIABLE);

		ac->preferred_zoneref = first_zones_zonelist(

			ac->zonelist, ac->highest_zoneidx, ac->nodemask);

		return;

	}

}

#else

static inline struct zone *mem_reliable_fallback_zone(gfp_t gfp_mask,

						      struct alloc_context *ac)

{

	return NULL;

}

static inline void mem_reliable_fallback_slowpath(gfp_t gfp_mask,

						  struct alloc_context *ac) {}

#endif



static inline struct page *

__alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,

						struct alloc_context *ac)
@@ -4080,8 +4126,10 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, 
	 */

	ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,

					ac->highest_zoneidx, ac->nodemask);

	if (!ac->preferred_zoneref->zone)

	if (!ac->preferred_zoneref->zone) {

		if (!mem_reliable_fallback_zone(gfp_mask, ac))

			goto nopage;

	}



	/*

	 * Check for insane configurations where the cpuset doesn't contain
@@ -4099,6 +4147,8 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, 
	if (alloc_flags & ALLOC_KSWAPD)

		wake_all_kswapds(order, gfp_mask, ac);



	mem_reliable_fallback_slowpath(gfp_mask, ac);



	/*

	 * The adjusted alloc_flags might result in immediate success, so try

	 * that first
@@ -4619,7 +4669,7 @@ static inline bool check_after_alloc(gfp_t *gfp, unsigned int order, 
	*_page = NULL;



out_retry:

	if (is_global_init(current)) {

	if (reliable_allow_fb_enabled() || is_global_init(current)) {

		*gfp &= ~GFP_RELIABLE;

		return true;

	}