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>,
Alexander Duyck <alexander.h.duyck@linux.intel.com>,
Minchan Kim <minchan@kernel.org>
Subject: [PATCH v4 5/8] mm/madvise: employ mmget_still_valid for write lock
Date: Wed, 12 Feb 2020 15:39:43 -0800 [thread overview]
Message-ID: <20200212233946.246210-6-minchan@kernel.org> (raw)
In-Reply-To: <20200212233946.246210-1-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 276b9d81c1dd..71f0ba199ae8 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -1120,6 +1120,8 @@ int do_madvise(struct task_struct *task, unsigned long start,
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);
}
@@ -1170,6 +1172,7 @@ int do_madvise(struct task_struct *task, unsigned long start,
}
out:
blk_finish_plug(&plug);
+skip_mm:
if (write)
up_write(&mm->mmap_sem);
else
--
2.25.0.225.g125e21ebc7-goog
next prev parent reply other threads:[~2020-02-12 23:40 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-12 23:39 [PATCH v4 0/8] introduce memory hinting API for external process Minchan Kim
2020-02-12 23:39 ` [PATCH v4 1/8] mm: pass task to do_madvise Minchan Kim
2020-02-13 0:21 ` Alexander Duyck
2020-02-13 17:02 ` Minchan Kim
2020-02-13 17:35 ` Jann Horn
2020-02-12 23:39 ` [PATCH v4 2/8] mm: introduce external memory hinting API Minchan Kim
2020-02-13 14:08 ` Jann Horn
2020-02-13 16:10 ` Minchan Kim
2020-02-12 23:39 ` [PATCH v4 3/8] mm: validate mm in do_madvise Minchan Kim
2020-02-12 23:39 ` [PATCH v4 4/8] mm: check fatal signal pending of target process Minchan Kim
2020-02-12 23:39 ` Minchan Kim [this message]
2020-02-12 23:39 ` [PATCH v4 6/8] mm/madvise: allow KSM hints for remote API Minchan Kim
2020-02-12 23:39 ` [PATCH v4 7/8] pid: export pidfd_get_pid Minchan Kim
2020-02-13 0:25 ` Alexander Duyck
2020-02-13 17:08 ` Minchan Kim
2020-02-12 23:39 ` [PATCH v4 8/8] mm: support both pid and pidfd for process_madvise Minchan Kim
2020-02-13 0:28 ` Alexander Duyck
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