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SeongJae Park
1c676e0d9b
PG_idle and PG_young allow the two PTE Accessed bit users, Idle Page Tracking and the reclaim logic concurrently work while not interfering with each other. That is, when they need to clear the Accessed bit, they set PG_young to represent the previous state of the bit, respectively. And when they need to read the bit, if the bit is cleared, they further read the PG_young to know whether the other has cleared the bit meanwhile or not. For yet another user of the PTE Accessed bit, we could add another page flag, or extend the mechanism to use the flags. For the DAMON usecase, however, we don't need to do that just yet. IDLE_PAGE_TRACKING and DAMON are mutually exclusive, so there's only ever going to be one user of the current set of flags. In this commit, we split out the CONFIG options to allow for the use of PG_young and PG_idle outside of idle page tracking. In the next commit, DAMON's reference implementation of the virtual memory address space monitoring primitives will use it. [[email protected]: set PAGE_EXTENSION for non-64BIT] Link: https://lkml.kernel.org/r/[email protected] [[email protected]: tweak Kconfig text] [[email protected]: hide PAGE_IDLE_FLAG from users] Link: https://lkml.kernel.org/r/[email protected] Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: SeongJae Park <[email protected]> Reviewed-by: Shakeel Butt <[email protected]> Reviewed-by: Fernand Sieber <[email protected]> Cc: Alexander Shishkin <[email protected]> Cc: Amit Shah <[email protected]> Cc: Benjamin Herrenschmidt <[email protected]> Cc: Brendan Higgins <[email protected]> Cc: David Hildenbrand <[email protected]> Cc: David Rientjes <[email protected]> Cc: David Woodhouse <[email protected]> Cc: Fan Du <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: Greg Thelen <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Joe Perches <[email protected]> Cc: Jonathan Cameron <[email protected]> Cc: Jonathan Corbet <[email protected]> Cc: Leonard Foerster <[email protected]> Cc: Marco Elver <[email protected]> Cc: Markus Boehme <[email protected]> Cc: Maximilian Heyne <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Minchan Kim <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Rik van Riel <[email protected]> Cc: Shuah Khan <[email protected]> Cc: Steven Rostedt (VMware) <[email protected]> Cc: Vladimir Davydov <[email protected]> Cc: Vlastimil Babka <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
92 lines
1.8 KiB
C
92 lines
1.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __LINUX_PAGE_EXT_H
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#define __LINUX_PAGE_EXT_H
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#include <linux/types.h>
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#include <linux/stacktrace.h>
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#include <linux/stackdepot.h>
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struct pglist_data;
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struct page_ext_operations {
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size_t offset;
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size_t size;
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bool (*need)(void);
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void (*init)(void);
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};
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#ifdef CONFIG_PAGE_EXTENSION
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enum page_ext_flags {
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PAGE_EXT_OWNER,
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PAGE_EXT_OWNER_ALLOCATED,
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#if defined(CONFIG_PAGE_IDLE_FLAG) && !defined(CONFIG_64BIT)
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PAGE_EXT_YOUNG,
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PAGE_EXT_IDLE,
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#endif
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};
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/*
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* Page Extension can be considered as an extended mem_map.
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* A page_ext page is associated with every page descriptor. The
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* page_ext helps us add more information about the page.
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* All page_ext are allocated at boot or memory hotplug event,
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* then the page_ext for pfn always exists.
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*/
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struct page_ext {
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unsigned long flags;
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};
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extern unsigned long page_ext_size;
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extern void pgdat_page_ext_init(struct pglist_data *pgdat);
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#ifdef CONFIG_SPARSEMEM
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static inline void page_ext_init_flatmem(void)
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{
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}
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extern void page_ext_init(void);
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static inline void page_ext_init_flatmem_late(void)
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{
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}
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#else
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extern void page_ext_init_flatmem(void);
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extern void page_ext_init_flatmem_late(void);
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static inline void page_ext_init(void)
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{
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}
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#endif
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struct page_ext *lookup_page_ext(const struct page *page);
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static inline struct page_ext *page_ext_next(struct page_ext *curr)
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{
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void *next = curr;
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next += page_ext_size;
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return next;
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}
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#else /* !CONFIG_PAGE_EXTENSION */
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struct page_ext;
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static inline void pgdat_page_ext_init(struct pglist_data *pgdat)
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{
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}
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static inline struct page_ext *lookup_page_ext(const struct page *page)
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{
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return NULL;
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}
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static inline void page_ext_init(void)
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{
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}
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static inline void page_ext_init_flatmem_late(void)
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{
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}
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static inline void page_ext_init_flatmem(void)
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{
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}
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#endif /* CONFIG_PAGE_EXTENSION */
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#endif /* __LINUX_PAGE_EXT_H */
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