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linux-next/include/linux/memory.h
David Hildenbrand 68c3a6ac65 drivers/base/memory.c: drop section_count
Patch series "mm: drop superfluous section checks when onlining/offlining".

Let's drop some superfluous section checks on the onlining/offlining path.

This patch (of 3):

Since commit c5e79ef561 ("mm/memory_hotplug.c: don't allow to
online/offline memory blocks with holes") we have a generic check in
offline_pages() that disallows offlining memory blocks with holes.

Memory blocks with missing sections are just another variant of these type
of blocks.  We can stop checking (and especially storing) present
sections.  A proper error message is now printed why offlining failed.

section_count was initially introduced in commit 0768121597 ("Driver
core: Add section count to memory_block struct") in order to detect when
it is okay to remove a memory block.  It was used in commit 26bbe7ef6d
("drivers/base/memory.c: prohibit offlining of memory blocks with missing
sections") to disallow offlining memory blocks with missing sections.  As
we refactored creation/removal of memory devices and have a proper check
for holes in place, we can drop the section_count.

This also removes a leftover comment regarding the mem_sysfs_mutex, which
was removed in commit 848e19ad3c ("drivers/base/memory.c: drop the
mem_sysfs_mutex").

Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Link: http://lkml.kernel.org/r/20200127110424.5757-2-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-07 10:43:40 -07:00

118 lines
3.7 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* include/linux/memory.h - generic memory definition
*
* This is mainly for topological representation. We define the
* basic "struct memory_block" here, which can be embedded in per-arch
* definitions or NUMA information.
*
* Basic handling of the devices is done in drivers/base/memory.c
* and system devices are handled in drivers/base/sys.c.
*
* Memory block are exported via sysfs in the class/memory/devices/
* directory.
*
*/
#ifndef _LINUX_MEMORY_H_
#define _LINUX_MEMORY_H_
#include <linux/node.h>
#include <linux/compiler.h>
#include <linux/mutex.h>
#include <linux/notifier.h>
#define MIN_MEMORY_BLOCK_SIZE (1UL << SECTION_SIZE_BITS)
struct memory_block {
unsigned long start_section_nr;
unsigned long state; /* serialized by the dev->lock */
int online_type; /* for passing data to online routine */
int phys_device; /* to which fru does this belong? */
struct device dev;
int nid; /* NID for this memory block */
};
int arch_get_memory_phys_device(unsigned long start_pfn);
unsigned long memory_block_size_bytes(void);
int set_memory_block_size_order(unsigned int order);
/* These states are exposed to userspace as text strings in sysfs */
#define MEM_ONLINE (1<<0) /* exposed to userspace */
#define MEM_GOING_OFFLINE (1<<1) /* exposed to userspace */
#define MEM_OFFLINE (1<<2) /* exposed to userspace */
#define MEM_GOING_ONLINE (1<<3)
#define MEM_CANCEL_ONLINE (1<<4)
#define MEM_CANCEL_OFFLINE (1<<5)
struct memory_notify {
unsigned long start_pfn;
unsigned long nr_pages;
int status_change_nid_normal;
int status_change_nid_high;
int status_change_nid;
};
struct notifier_block;
struct mem_section;
/*
* Priorities for the hotplug memory callback routines (stored in decreasing
* order in the callback chain)
*/
#define SLAB_CALLBACK_PRI 1
#define IPC_CALLBACK_PRI 10
#ifndef CONFIG_MEMORY_HOTPLUG_SPARSE
static inline void memory_dev_init(void)
{
return;
}
static inline int register_memory_notifier(struct notifier_block *nb)
{
return 0;
}
static inline void unregister_memory_notifier(struct notifier_block *nb)
{
}
static inline int memory_notify(unsigned long val, void *v)
{
return 0;
}
#else
extern int register_memory_notifier(struct notifier_block *nb);
extern void unregister_memory_notifier(struct notifier_block *nb);
int create_memory_block_devices(unsigned long start, unsigned long size);
void remove_memory_block_devices(unsigned long start, unsigned long size);
extern void memory_dev_init(void);
extern int memory_notify(unsigned long val, void *v);
extern struct memory_block *find_memory_block(struct mem_section *);
typedef int (*walk_memory_blocks_func_t)(struct memory_block *, void *);
extern int walk_memory_blocks(unsigned long start, unsigned long size,
void *arg, walk_memory_blocks_func_t func);
extern int for_each_memory_block(void *arg, walk_memory_blocks_func_t func);
#define CONFIG_MEM_BLOCK_SIZE (PAGES_PER_SECTION<<PAGE_SHIFT)
#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
#ifdef CONFIG_MEMORY_HOTPLUG
#define hotplug_memory_notifier(fn, pri) ({ \
static __meminitdata struct notifier_block fn##_mem_nb =\
{ .notifier_call = fn, .priority = pri };\
register_memory_notifier(&fn##_mem_nb); \
})
#define register_hotmemory_notifier(nb) register_memory_notifier(nb)
#define unregister_hotmemory_notifier(nb) unregister_memory_notifier(nb)
#else
#define hotplug_memory_notifier(fn, pri) ({ 0; })
/* These aren't inline functions due to a GCC bug. */
#define register_hotmemory_notifier(nb) ({ (void)(nb); 0; })
#define unregister_hotmemory_notifier(nb) ({ (void)(nb); })
#endif
/*
* Kernel text modification mutex, used for code patching. Users of this lock
* can sleep.
*/
extern struct mutex text_mutex;
#endif /* _LINUX_MEMORY_H_ */