[PATCH 1/2] uprobes/core: Make background page replacement logic account for rss_stat counters

From: Srikar Dronamraju
Date: Wed Apr 11 2012 - 06:43:02 EST


From: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>

Background page replacement logic adds a new anonymous page instead of a
filebacked(while inserting a breakpoint) / anonymous page(while removing a
breakpoint). Hence logic should take care to update the rss_stat counters
accordingly. This bug became apparent courtesy commit c3f0327f8e9d7

Signed-off-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
---
kernel/events/uprobes.c | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 29e881b..c5caeec 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -160,6 +160,11 @@ static int __replace_page(struct vm_area_struct *vma, struct page *page, struct
get_page(kpage);
page_add_new_anon_rmap(kpage, vma, addr);

+ if (!PageAnon(page)) {
+ dec_mm_counter(mm, MM_FILEPAGES);
+ inc_mm_counter(mm, MM_ANONPAGES);
+ }
+
flush_cache_page(vma, addr, pte_pfn(*ptep));
ptep_clear_flush(vma, addr, ptep);
set_pte_at_notify(mm, addr, ptep, mk_pte(kpage, vma->vm_page_prot));


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