| Message ID | 20210129234548.10054-1-georgi.djakov@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm/page_owner: Record the timestamp of all pages during free | expand |
On 1/30/21 12:45 AM, Georgi Djakov wrote: > Collect the time when each allocation is freed, to help with memory > analysis with kdump/ramdump. > > Having another timestamp when we free the page helps for debugging > page migration issues. For example both alloc and free timestamps > being the same can gave hints that there is an issue with migrating > memory, as opposed to a page just being dropped during migration. Besides crash dump analysis, we should also provide this timestamp in the page_owner file and dump_page()? > Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org> > --- > Documentation/vm/page_owner.rst | 2 +- > mm/page_owner.c | 5 +++++ > 2 files changed, 6 insertions(+), 1 deletion(-) > > diff --git a/Documentation/vm/page_owner.rst b/Documentation/vm/page_owner.rst > index 4e67c2e9bbed..5d7a62c2be28 100644 > --- a/Documentation/vm/page_owner.rst > +++ b/Documentation/vm/page_owner.rst > @@ -47,7 +47,7 @@ size change due to this facility. > > text data bss dec hex filename > 48800 2445 644 51889 cab1 mm/page_alloc.o > - 6574 108 29 6711 1a37 mm/page_owner.o > + 6644 108 29 6777 1a79 mm/page_owner.o > 1025 8 8 1041 411 mm/page_ext.o > > Although, roughly, 8 KB code is added in total, page_alloc.o increase by > diff --git a/mm/page_owner.c b/mm/page_owner.c > index d15c7c4994f5..fbdf064e7494 100644 > --- a/mm/page_owner.c > +++ b/mm/page_owner.c > @@ -27,6 +27,7 @@ struct page_owner { > depot_stack_handle_t handle; > depot_stack_handle_t free_handle; > u64 ts_nsec; > + u64 free_ts_nsec; > pid_t pid; > }; > > @@ -148,6 +149,7 @@ void __reset_page_owner(struct page *page, unsigned int order) > struct page_ext *page_ext; > depot_stack_handle_t handle = 0; > struct page_owner *page_owner; > + u64 free_ts_nsec = local_clock(); > > handle = save_stack(GFP_NOWAIT | __GFP_NOWARN); > > @@ -158,6 +160,7 @@ void __reset_page_owner(struct page *page, unsigned int order) > __clear_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags); > page_owner = get_page_owner(page_ext); > page_owner->free_handle = handle; > + page_owner->free_ts_nsec = free_ts_nsec; > page_ext = page_ext_next(page_ext); > } > } > @@ -177,6 +180,7 @@ static inline void __set_page_owner_handle(struct page *page, > page_owner->last_migrate_reason = -1; > page_owner->pid = current->pid; > page_owner->ts_nsec = local_clock(); > + page_owner->free_ts_nsec = 0; Might be more useful not to reset the time of previous free when the page is reallocated? > __set_bit(PAGE_EXT_OWNER, &page_ext->flags); > __set_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags); > > @@ -243,6 +247,7 @@ void __copy_page_owner(struct page *oldpage, struct page *newpage) > new_page_owner->handle = old_page_owner->handle; > new_page_owner->pid = old_page_owner->pid; > new_page_owner->ts_nsec = old_page_owner->ts_nsec; > + new_page_owner->free_ts_nsec = old_page_owner->ts_nsec; > > /* > * We don't clear the bit on the oldpage as it's going to be freed >
diff --git a/Documentation/vm/page_owner.rst b/Documentation/vm/page_owner.rst index 4e67c2e9bbed..5d7a62c2be28 100644 --- a/Documentation/vm/page_owner.rst +++ b/Documentation/vm/page_owner.rst @@ -47,7 +47,7 @@ size change due to this facility. text data bss dec hex filename 48800 2445 644 51889 cab1 mm/page_alloc.o - 6574 108 29 6711 1a37 mm/page_owner.o + 6644 108 29 6777 1a79 mm/page_owner.o 1025 8 8 1041 411 mm/page_ext.o Although, roughly, 8 KB code is added in total, page_alloc.o increase by diff --git a/mm/page_owner.c b/mm/page_owner.c index d15c7c4994f5..fbdf064e7494 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -27,6 +27,7 @@ struct page_owner { depot_stack_handle_t handle; depot_stack_handle_t free_handle; u64 ts_nsec; + u64 free_ts_nsec; pid_t pid; }; @@ -148,6 +149,7 @@ void __reset_page_owner(struct page *page, unsigned int order) struct page_ext *page_ext; depot_stack_handle_t handle = 0; struct page_owner *page_owner; + u64 free_ts_nsec = local_clock(); handle = save_stack(GFP_NOWAIT | __GFP_NOWARN); @@ -158,6 +160,7 @@ void __reset_page_owner(struct page *page, unsigned int order) __clear_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags); page_owner = get_page_owner(page_ext); page_owner->free_handle = handle; + page_owner->free_ts_nsec = free_ts_nsec; page_ext = page_ext_next(page_ext); } } @@ -177,6 +180,7 @@ static inline void __set_page_owner_handle(struct page *page, page_owner->last_migrate_reason = -1; page_owner->pid = current->pid; page_owner->ts_nsec = local_clock(); + page_owner->free_ts_nsec = 0; __set_bit(PAGE_EXT_OWNER, &page_ext->flags); __set_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags); @@ -243,6 +247,7 @@ void __copy_page_owner(struct page *oldpage, struct page *newpage) new_page_owner->handle = old_page_owner->handle; new_page_owner->pid = old_page_owner->pid; new_page_owner->ts_nsec = old_page_owner->ts_nsec; + new_page_owner->free_ts_nsec = old_page_owner->ts_nsec; /* * We don't clear the bit on the oldpage as it's going to be freed
Collect the time when each allocation is freed, to help with memory analysis with kdump/ramdump. Having another timestamp when we free the page helps for debugging page migration issues. For example both alloc and free timestamps being the same can gave hints that there is an issue with migrating memory, as opposed to a page just being dropped during migration. Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org> --- Documentation/vm/page_owner.rst | 2 +- mm/page_owner.c | 5 +++++ 2 files changed, 6 insertions(+), 1 deletion(-)