From: Minchan Kim <minchan@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
linux-api@vger.kernel.org, oleksandr@redhat.com,
Suren Baghdasaryan <surenb@google.com>,
Tim Murray <timmurray@google.com>,
Daniel Colascione <dancol@google.com>,
Sandeep Patil <sspatil@google.com>,
Sonny Rao <sonnyrao@google.com>,
Brian Geffon <bgeffon@google.com>, Michal Hocko <mhocko@suse.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Shakeel Butt <shakeelb@google.com>,
John Dias <joaodias@google.com>,
Joel Fernandes <joel@joelfernandes.org>,
Minchan Kim <minchan@kernel.org>
Subject: [PATCH v3 3/5] mm/madvise: employ mmget_still_valid for write lock
Date: Mon, 27 Jan 2020 16:16:39 -0800 [thread overview]
Message-ID: <20200128001641.5086-4-minchan@kernel.org> (raw)
In-Reply-To: <20200128001641.5086-1-minchan@kernel.org>
From: Oleksandr Natalenko <oleksandr@redhat.com>
Do the very same trick as we already do since 04f5866e41fb. KSM hints
will require locking mmap_sem for write since they modify vm_flags, so
for remote KSM hinting this additional check is needed.
Signed-off-by: Oleksandr Natalenko <oleksandr@redhat.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
---
mm/madvise.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/mm/madvise.c b/mm/madvise.c
index 00ffa7e92f79..bc0a72dbf80e 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -1061,6 +1061,8 @@ static int madvise_common(struct task_struct *task, struct mm_struct *mm,
if (write) {
if (down_write_killable(&mm->mmap_sem))
return -EINTR;
+ if (current->mm != mm && !mmget_still_valid(mm))
+ goto skip_mm;
} else {
down_read(&mm->mmap_sem);
}
@@ -1111,6 +1113,7 @@ static int madvise_common(struct task_struct *task, struct mm_struct *mm,
}
out:
blk_finish_plug(&plug);
+skip_mm:
if (write)
up_write(&mm->mmap_sem);
else
--
2.25.0.341.g760bfbb309-goog
next prev parent reply other threads:[~2020-01-28 0:17 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-28 0:16 [PATCH v3 0/5] introduce memory hinting API for external process Minchan Kim
2020-01-28 0:16 ` [PATCH v3 1/5] mm: factor out madvise's core functionality Minchan Kim
2020-02-10 23:00 ` Alexander Duyck
2020-02-11 21:08 ` Minchan Kim
2020-01-28 0:16 ` [PATCH v3 2/5] mm: introduce external memory hinting API Minchan Kim
2020-02-10 17:50 ` Suren Baghdasaryan
2020-02-10 21:27 ` Minchan Kim
2020-01-28 0:16 ` Minchan Kim [this message]
2020-01-28 0:16 ` [PATCH v3 4/5] mm/madvise: allow KSM hints for remote API Minchan Kim
2020-01-28 0:16 ` [PATCH v3 5/5] mm: support both pid and pidfd for process_madvise Minchan Kim
2020-02-10 23:12 ` Alexander Duyck
2020-02-11 21:11 ` Minchan Kim
2020-02-10 21:29 ` [PATCH v3 0/5] introduce memory hinting API for external process Minchan Kim
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