linux_dsm_epyc7002/include/linux/page_ext.h
Sergei Rogachev 94f759d62b mm/page_owner.c: remove unnecessary stack_trace field
Page owner uses the page_ext structure to keep meta-information for every
page in the system.  The structure also contains a field of type 'struct
stack_trace', page owner uses this field during invocation of the function
save_stack_trace.  It is easy to notice that keeping a copy of this
structure for every page in the system is very inefficiently in terms of
memory.

The patch removes this unnecessary field of page_ext and forces page owner
to use a stack_trace structure allocated on the stack.

[akpm@linux-foundation.org: use struct initializers]
Signed-off-by: Sergei Rogachev <rogachevsergei@gmail.com>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-11 17:06:07 -08:00

85 lines
1.8 KiB
C

#ifndef __LINUX_PAGE_EXT_H
#define __LINUX_PAGE_EXT_H
#include <linux/types.h>
#include <linux/stacktrace.h>
struct pglist_data;
struct page_ext_operations {
bool (*need)(void);
void (*init)(void);
};
#ifdef CONFIG_PAGE_EXTENSION
/*
* page_ext->flags bits:
*
* PAGE_EXT_DEBUG_POISON is set for poisoned pages. This is used to
* implement generic debug pagealloc feature. The pages are filled with
* poison patterns and set this flag after free_pages(). The poisoned
* pages are verified whether the patterns are not corrupted and clear
* the flag before alloc_pages().
*/
enum page_ext_flags {
PAGE_EXT_DEBUG_POISON, /* Page is poisoned */
PAGE_EXT_DEBUG_GUARD,
PAGE_EXT_OWNER,
};
/*
* Page Extension can be considered as an extended mem_map.
* A page_ext page is associated with every page descriptor. The
* page_ext helps us add more information about the page.
* All page_ext are allocated at boot or memory hotplug event,
* then the page_ext for pfn always exists.
*/
struct page_ext {
unsigned long flags;
#ifdef CONFIG_PAGE_OWNER
unsigned int order;
gfp_t gfp_mask;
unsigned int nr_entries;
unsigned long trace_entries[8];
#endif
};
extern void pgdat_page_ext_init(struct pglist_data *pgdat);
#ifdef CONFIG_SPARSEMEM
static inline void page_ext_init_flatmem(void)
{
}
extern void page_ext_init(void);
#else
extern void page_ext_init_flatmem(void);
static inline void page_ext_init(void)
{
}
#endif
struct page_ext *lookup_page_ext(struct page *page);
#else /* !CONFIG_PAGE_EXTENSION */
struct page_ext;
static inline void pgdat_page_ext_init(struct pglist_data *pgdat)
{
}
static inline struct page_ext *lookup_page_ext(struct page *page)
{
return NULL;
}
static inline void page_ext_init(void)
{
}
static inline void page_ext_init_flatmem(void)
{
}
#endif /* CONFIG_PAGE_EXTENSION */
#endif /* __LINUX_PAGE_EXT_H */