[PATCH 2/2] mm: Generate events when tasks change their memory
From: Pavel Emelyanov <hidden>
Date: 2012-11-30 17:56:39
Subsystem:
memory management, memory management - core, memory management - thp (transparent huge page), memory mapping, memory mapping - madvise (memory advice), the rest, tracing · Maintainers:
Andrew Morton, David Hildenbrand, Lorenzo Stoakes, Liam R. Howlett, Linus Torvalds, Steven Rostedt, Masami Hiramatsu
When vma tracing is ON, the vma memory is remaped to read-only state. Later in the pagefault handlers the event is sent via tracing engine. With the existing on/off events this makes it possible to monitor how processes modify their memory contents. Signed-off-by: Pavel Emelyanov <redacted> --- include/linux/mm.h | 3 +++ include/trace/events/mmu.h | 18 ++++++++++++++++++ mm/huge_memory.c | 4 ++++ mm/madvise.c | 11 +++++++++++ mm/memory.c | 2 ++ mm/mprotect.c | 2 +- 6 files changed, 39 insertions(+), 1 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index c7fad8d..7e5fe10 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h@@ -1082,6 +1082,9 @@ extern unsigned long do_mremap(unsigned long addr, extern int mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, unsigned long start, unsigned long end, unsigned long newflags); +void change_protection(struct vm_area_struct *vma, + unsigned long addr, unsigned long end, pgprot_t newprot, + int dirty_accountable); /* * doesn't attempt to fault and will return short.
diff --git a/include/trace/events/mmu.h b/include/trace/events/mmu.h
index 71b1ba6..d1bff37 100644
--- a/include/trace/events/mmu.h
+++ b/include/trace/events/mmu.h@@ -24,6 +24,24 @@ TRACE_EVENT_CONDITION(mmu_trace_on, TP_printk("start %#lx", __entry->start) ); +TRACE_EVENT_CONDITION(mmu_page_mod, + TP_PROTO(struct vm_area_struct *vma, unsigned long vaddr), + + TP_ARGS(vma, vaddr), + + TP_CONDITION(vma->vm_flags & VM_TRACE), + + TP_STRUCT__entry( + __field(unsigned long, vaddr) + ), + + TP_fast_assign( + __entry->vaddr = vaddr; + ), + + TP_printk("vaddr %#lx", __entry->vaddr) +); + TRACE_EVENT_CONDITION(mmu_trace_off, TP_PROTO(struct vm_area_struct *vma),
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 40f17c3..7a93683 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c@@ -22,6 +22,8 @@ #include <asm/pgalloc.h> #include "internal.h" +#include <trace/events/mmu.h> + /* * By default transparent hugepage support is enabled for all mappings * and khugepaged scans all mappings. Defrag is only invoked by
@@ -888,6 +890,8 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long mmun_start; /* For mmu_notifiers */ unsigned long mmun_end; /* For mmu_notifiers */ + trace_mmu_page_mod(vma, address); + VM_BUG_ON(!vma->anon_vma); spin_lock(&mm->page_table_lock); if (unlikely(!pmd_same(*pmd, orig_pmd)))
diff --git a/mm/madvise.c b/mm/madvise.c
index 65633e9..05361c2 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c@@ -64,6 +64,17 @@ static long madvise_behavior(struct vm_area_struct * vma, new_flags |= VM_DONTCOPY; break; case MADV_DOTRACE: + /* + * Protect pages to be read-only and force tasks to generate + * #PFs on modification. + * + * It should be done before issuing trace-on event. Otherwise + * we're leaving a short window after the 'on' event when tasks + * can still modify pages. + */ + change_protection(vma, start, end, + vm_get_page_prot(vma->vm_flags & ~VM_READ), + vma_wants_writenotify(vma)); trace_mmu_trace_on(vma); new_flags |= VM_TRACE; break;
diff --git a/mm/memory.c b/mm/memory.c
index a6f5951..1dd30ae 100644
--- a/mm/memory.c
+++ b/mm/memory.c@@ -2533,6 +2533,8 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long mmun_start = 0; /* For mmu_notifiers */ unsigned long mmun_end = 0; /* For mmu_notifiers */ + trace_mmu_page_mod(vma, address); + old_page = vm_normal_page(vma, address, orig_pte); if (!old_page) { /*
diff --git a/mm/mprotect.c b/mm/mprotect.c
index a409926..91c2266 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c@@ -119,7 +119,7 @@ static inline void change_pud_range(struct vm_area_struct *vma, pgd_t *pgd, } while (pud++, addr = next, addr != end); } -static void change_protection(struct vm_area_struct *vma, +void change_protection(struct vm_area_struct *vma, unsigned long addr, unsigned long end, pgprot_t newprot, int dirty_accountable) {
--
1.7.6.5
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