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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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48c96a3685
This is the page owner tracking code which is introduced so far ago. It is resident on Andrew's tree, though, nobody tried to upstream so it remain as is. Our company uses this feature actively to debug memory leak or to find a memory hogger so I decide to upstream this feature. This functionality help us to know who allocates the page. When allocating a page, we store some information about allocation in extra memory. Later, if we need to know status of all pages, we can get and analyze it from this stored information. In previous version of this feature, extra memory is statically defined in struct page, but, in this version, extra memory is allocated outside of struct page. It enables us to turn on/off this feature at boottime without considerable memory waste. Although we already have tracepoint for tracing page allocation/free, using it to analyze page owner is rather complex. We need to enlarge the trace buffer for preventing overlapping until userspace program launched. And, launched program continually dump out the trace buffer for later analysis and it would change system behaviour with more possibility rather than just keeping it in memory, so bad for debug. Moreover, we can use page_owner feature further for various purposes. For example, we can use it for fragmentation statistics implemented in this patch. And, I also plan to implement some CMA failure debugging feature using this interface. I'd like to give the credit for all developers contributed this feature, but, it's not easy because I don't know exact history. Sorry about that. Below is people who has "Signed-off-by" in the patches in Andrew's tree. Contributor: Alexander Nyberg <alexn@dsv.su.se> Mel Gorman <mgorman@suse.de> Dave Hansen <dave@linux.vnet.ibm.com> Minchan Kim <minchan@kernel.org> Michal Nazarewicz <mina86@mina86.com> Andrew Morton <akpm@linux-foundation.org> Jungsoo Son <jungsoo.son@lge.com> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Dave Hansen <dave@sr71.net> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Jungsoo Son <jungsoo.son@lge.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
85 lines
1.8 KiB
C
85 lines
1.8 KiB
C
#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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struct pglist_data;
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struct page_ext_operations {
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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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/*
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* page_ext->flags bits:
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*
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* PAGE_EXT_DEBUG_POISON is set for poisoned pages. This is used to
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* implement generic debug pagealloc feature. The pages are filled with
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* poison patterns and set this flag after free_pages(). The poisoned
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* pages are verified whether the patterns are not corrupted and clear
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* the flag before alloc_pages().
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*/
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enum page_ext_flags {
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PAGE_EXT_DEBUG_POISON, /* Page is poisoned */
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PAGE_EXT_DEBUG_GUARD,
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PAGE_EXT_OWNER,
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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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#ifdef CONFIG_PAGE_OWNER
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unsigned int order;
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gfp_t gfp_mask;
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struct stack_trace trace;
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unsigned long trace_entries[8];
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#endif
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};
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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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#else
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extern void page_ext_init_flatmem(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(struct page *page);
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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(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(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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