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rss_stat: add support to detect RSS updates of external mm

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When a process updates the RSS of a different process, the rss_stat
tracepoint appears in the context of the process doing the update.  This
can confuse userspace that the RSS of process doing the update is
updated, while in reality a different process's RSS was updated.

This issue happens in reclaim paths such as with direct reclaim or
background reclaim.

This patch adds more information to the tracepoint about whether the mm
being updated belongs to the current process's context (curr field).  We
also include a hash of the mm pointer so that the process who the mm
belongs to can be uniquely identified (mm_id field).

Also vsprintf.c is refactored a bit to allow reuse of hashing code.

[akpm@linux-foundation.org: remove unused local `str']
[joelaf@google.com: inline call to ptr_to_hashval]
  Link: http://lore.kernel.org/r/20191113153816.14b95acd@gandalf.local.home
  Link: http://lkml.kernel.org/r/20191114164622.GC233237@google.com
Link: http://lkml.kernel.org/r/20191106024452.81923-1-joel@joelfernandes.org
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reported-by: Ioannis Ilkos <ilkos@google.com>
Acked-by: Petr Mladek <pmladek@suse.com>	[lib/vsprintf.c]
Cc: Tim Murray <timmurray@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Carmen Jackson <carmenjackson@google.com>
Cc: Mayank Gupta <mayankgupta@google.com>
Cc: Daniel Colascione <dancol@google.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Joel Fernandes (Google)
2019-11-30 17:50:33 -08:00
committed by Linus Torvalds
parent b3d1411b67
commit e4dcad204d
5 changed files with 69 additions and 23 deletions
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8
include/linux/mm.h
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@@ -1643,27 +1643,27 @@ static inline unsigned long get_mm_counter(struct mm_struct *mm, int member)
return (unsigned long)val;
}
void mm_trace_rss_stat(int member, long count);
void mm_trace_rss_stat(struct mm_struct *mm, int member, long count);
static inline void add_mm_counter(struct mm_struct *mm, int member, long value)
{
long count = atomic_long_add_return(value, &mm->rss_stat.count[member]);
mm_trace_rss_stat(member, count);
mm_trace_rss_stat(mm, member, count);
}
static inline void inc_mm_counter(struct mm_struct *mm, int member)
{
long count = atomic_long_inc_return(&mm->rss_stat.count[member]);
mm_trace_rss_stat(member, count);
mm_trace_rss_stat(mm, member, count);
}
static inline void dec_mm_counter(struct mm_struct *mm, int member)
{
long count = atomic_long_dec_return(&mm->rss_stat.count[member]);
mm_trace_rss_stat(member, count);
mm_trace_rss_stat(mm, member, count);
}
/* Optimized variant when page is already known not to be PageAnon */