From 31e369115a8d48e07db687a85484005383a85427 Mon Sep 17 00:00:00 2001 From: Georgi Djakov Date: Tue, 6 Jul 2021 11:33:57 +0000 Subject: [PATCH] mm/page_owner: record the timestamp of all pages during free mainline inclusion from mainline-5.13-rc1 commit 866b485262173a2b873386162b2ddcfbcb542b4a category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I3ZD1N CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=866b485262173a2b873386162b2ddcfbcb542b4a ------------------------------------------------- Collect the time when each allocation is freed, to help with memory analysis with kdump/ramdump. Add the timestamp also in the page_owner debugfs file and print it in dump_page(). 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. Link: https://lkml.kernel.org/r/20210203175905.12267-1-georgi.djakov@linaro.org Signed-off-by: Georgi Djakov Acked-by: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds (cherry picked from commit 866b485262173a2b873386162b2ddcfbcb542b4a) Signed-off-by: Yongqiang Liu Reviewed-by: tong tiangen Signed-off-by: Zheng Zengkai --- Documentation/vm/page_owner.rst | 2 +- mm/page_owner.c | 12 ++++++++---- 2 files changed, 9 insertions(+), 5 deletions(-) diff --git a/Documentation/vm/page_owner.rst b/Documentation/vm/page_owner.rst index 4e67c2e9bbed..2175465c9bf2 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 + 6662 108 29 6799 1a8f 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 af464bb7fbe7..5b93fc85dc73 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); } } @@ -243,6 +246,7 @@ 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 @@ -356,10 +360,10 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn, return -ENOMEM; ret = snprintf(kbuf, count, - "Page allocated via order %u, mask %#x(%pGg), pid %d, ts %llu ns\n", + "Page allocated via order %u, mask %#x(%pGg), pid %d, ts %llu ns, free_ts %llu ns\n", page_owner->order, page_owner->gfp_mask, &page_owner->gfp_mask, page_owner->pid, - page_owner->ts_nsec); + page_owner->ts_nsec, page_owner->free_ts_nsec); if (ret >= count) goto err; @@ -435,9 +439,9 @@ void __dump_page_owner(struct page *page) else pr_alert("page_owner tracks the page as freed\n"); - pr_alert("page last allocated via order %u, migratetype %s, gfp_mask %#x(%pGg), pid %d, ts %llu\n", + pr_alert("page last allocated via order %u, migratetype %s, gfp_mask %#x(%pGg), pid %d, ts %llu, free_ts %llu\n", page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask, - page_owner->pid, page_owner->ts_nsec); + page_owner->pid, page_owner->ts_nsec, page_owner->free_ts_nsec); handle = READ_ONCE(page_owner->handle); if (!handle) { -- GitLab