[tip:perf/uprobes] uprobes/core: Make background page replacement logic account for rss_stat counters

[tip-bot for Srikar Dronamraju]

Commit-ID:  7396fa818d6278694a44840f389ddc40a3269a9a
Gitweb:     http://git.kernel.org/tip/7396fa818d6278694a44840f389ddc40a3269a9a
Author:     Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
AuthorDate: Wed, 11 Apr 2012 16:05:16 +0530
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Sat, 14 Apr 2012 13:25:47 +0200

uprobes/core: Make background page replacement logic account for rss_stat counters

Background page replacement logic adds a new anonymous page
instead of a file backed (while inserting a breakpoint) /
anonymous page (while removing a breakpoint).

Hence the uprobes logic should take care to update the
task->ss_stat counters accordingly.

This bug became apparent courtesy of commit c3f0327f8e9d
("mm: add rss counters consistency check").

Signed-off-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxx>
Cc: Jim Keniston <jkenisto@xxxxxxxxxxxxxxxxxx>
Cc: Linux-mm <linux-mm@xxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxxxxx>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: Anton Arapov <anton@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20120411103516.23245.2700.sendpatchset@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 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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