From: Vlastimil Babka <vbabka@xxxxxxx> Subject: mm, page_owner: make init_pages_in_zone() faster In init_pages_in_zone() we currently use the generic set_page_owner() function to initialize page_owner info for early allocated pages. This means we needlessly do lookup_page_ext() twice for each page, and more importantly save_stack(), which has to unwind the stack and find the corresponding stack depot handle. Because the stack is always the same for the initialization, unwind it once in init_pages_in_zone() and reuse the handle. Also avoid the repeated lookup_page_ext(). This can significantly reduce boot times with page_owner=on on large machines, especially for kernels built without frame pointer, where the stack unwinding is noticeably slower. [vbabka@xxxxxxx: don't duplicate code of __set_page_owner(), per Michal Hocko] [akpm@xxxxxxxxxxxxxxxxxxxx: coding-style fixes] [vbabka@xxxxxxx: create statically allocated fake stack trace for early allocated pages, per Michal] Link: http://lkml.kernel.org/r/45813564-2342-fc8d-d31a-f4b68a724325@xxxxxxx Link: http://lkml.kernel.org/r/20170720134029.25268-2-vbabka@xxxxxxx Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Cc: Yang Shi <yang.shi@xxxxxxxxxx> Cc: Laura Abbott <labbott@xxxxxxxxxx> Cc: Vinayak Menon <vinmenon@xxxxxxxxxxxxxx> Cc: zhong jiang <zhongjiang@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/page_owner.c | 52 ++++++++++++++++++++++++++++------------------ 1 file changed, 32 insertions(+), 20 deletions(-) diff -puN mm/page_owner.c~mm-page_owner-make-init_pages_in_zone-faster mm/page_owner.c --- a/mm/page_owner.c~mm-page_owner-make-init_pages_in_zone-faster +++ a/mm/page_owner.c @@ -30,6 +30,7 @@ DEFINE_STATIC_KEY_FALSE(page_owner_inite static depot_stack_handle_t dummy_handle; static depot_stack_handle_t failure_handle; +static depot_stack_handle_t early_handle; static void init_early_allocated_pages(void); @@ -53,7 +54,7 @@ static bool need_page_owner(void) return true; } -static noinline void register_dummy_stack(void) +static __always_inline depot_stack_handle_t create_dummy_stack(void) { unsigned long entries[4]; struct stack_trace dummy; @@ -64,21 +65,22 @@ static noinline void register_dummy_stac dummy.skip = 0; save_stack_trace(&dummy); - dummy_handle = depot_save_stack(&dummy, GFP_KERNEL); + return depot_save_stack(&dummy, GFP_KERNEL); } -static noinline void register_failure_stack(void) +static noinline void register_dummy_stack(void) { - unsigned long entries[4]; - struct stack_trace failure; + dummy_handle = create_dummy_stack(); +} - failure.nr_entries = 0; - failure.max_entries = ARRAY_SIZE(entries); - failure.entries = &entries[0]; - failure.skip = 0; +static noinline void register_failure_stack(void) +{ + failure_handle = create_dummy_stack(); +} - save_stack_trace(&failure); - failure_handle = depot_save_stack(&failure, GFP_KERNEL); +static noinline void register_early_stack(void) +{ + early_handle = create_dummy_stack(); } static void init_page_owner(void) @@ -88,6 +90,7 @@ static void init_page_owner(void) register_dummy_stack(); register_failure_stack(); + register_early_stack(); static_branch_enable(&page_owner_inited); init_early_allocated_pages(); } @@ -165,17 +168,13 @@ static noinline depot_stack_handle_t sav return handle; } -noinline void __set_page_owner(struct page *page, unsigned int order, - gfp_t gfp_mask) +static inline void __set_page_owner_handle(struct page_ext *page_ext, + depot_stack_handle_t handle, unsigned int order, gfp_t gfp_mask) { - struct page_ext *page_ext = lookup_page_ext(page); struct page_owner *page_owner; - if (unlikely(!page_ext)) - return; - page_owner = get_page_owner(page_ext); - page_owner->handle = save_stack(gfp_mask); + page_owner->handle = handle; page_owner->order = order; page_owner->gfp_mask = gfp_mask; page_owner->last_migrate_reason = -1; @@ -183,6 +182,19 @@ noinline void __set_page_owner(struct pa __set_bit(PAGE_EXT_OWNER, &page_ext->flags); } +noinline void __set_page_owner(struct page *page, unsigned int order, + gfp_t gfp_mask) +{ + struct page_ext *page_ext = lookup_page_ext(page); + depot_stack_handle_t handle; + + if (unlikely(!page_ext)) + return; + + handle = save_stack(gfp_mask); + __set_page_owner_handle(page_ext, handle, order, gfp_mask); +} + void __set_page_owner_migrate_reason(struct page *page, int reason) { struct page_ext *page_ext = lookup_page_ext(page); @@ -565,12 +577,12 @@ static void init_pages_in_zone(pg_data_t if (unlikely(!page_ext)) continue; - /* Maybe overraping zone */ + /* Maybe overlapping zone */ if (test_bit(PAGE_EXT_OWNER, &page_ext->flags)) continue; /* Found early allocated page */ - set_page_owner(page, 0, 0); + __set_page_owner_handle(page_ext, early_handle, 0, 0); count++; } } _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
