From nobody Tue Dec 16 05:46:58 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A401F2253EB for ; Thu, 6 Feb 2025 06:15:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738822526; cv=none; b=oAWkh7PFvyJP3RJ5hLzxketvjuSnChwwT8YdPTDi9xiRQBcQi6Kp4bFgx81eg9XV0MRYwHM+jlsr2Xo0Dc11V862rDPqsUH1ldO77ockxmmkgahh3TLXza4iL4obWmlIkCQPGx20RgCN96lOAWdB6RPdL9glFmZ1M1obrW+dX60= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738822526; c=relaxed/simple; bh=MP/17pf09yAFjnq6HfK1rSNsdKEXlrcNK/A1rjmLh9Y=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=XFmwz9ImJdGaWghZqV/31fkrtmYZoHqHmE06CqRBRzq6l9jKTs6vuOE9qLnKW2muhBPWo6IJicCKd0VYIMXHPkQWVgkch3PQn5q12+O0iUvPZKISAW6GePSMijrwnyydsMa27QGM465306WgbE3sV0rhHaQaoOeJQ6Xgj/RjqUU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=AeS+zBDr; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="AeS+zBDr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E5517C4CEE7; Thu, 6 Feb 2025 06:15:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1738822526; bh=MP/17pf09yAFjnq6HfK1rSNsdKEXlrcNK/A1rjmLh9Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AeS+zBDrcocIE5whSD/5gWTiHktVgl4p1z2AIiKeTcCh7xmQYLD+OXL/RaZfFtNcu hV1sCJcNigWgqPbttaPV4aOO1TIGzB6zT9MtTB+m3BwqfA2+u4O+xc8GLeo8W9DGds x/93/07bnlYUuqh3x8jnyxl6WwwrXLZigIC2mljeqwpA2HmsX3TgbDO+Cm91Gdq4C+ cBU/LRxPoRAAuv426uEieDoORu6nhMXi7jb0qNlNssLt7jWZwV6J4rVPBQ5G9ittRh Sb1TCC8ZuELFpKY3xHwi1CO6RGRYiv1weim8TPZB9h22iVgvfa+V83ScIn6iNEVS0V URqSXH8iKa+hg== From: SeongJae Park To: Andrew Morton Cc: SeongJae Park , "Liam R. Howlett" , David Hildenbrand , Davidlohr Bueso , Lorenzo Stoakes , Shakeel Butt , Vlastimil Babka , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 4/4] mm/madvise: remove redundant mmap_lock operations from process_madvise() Date: Wed, 5 Feb 2025 22:15:17 -0800 Message-Id: <20250206061517.2958-5-sj@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250206061517.2958-1-sj@kernel.org> References: <20250206061517.2958-1-sj@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Optimize redundant mmap lock operations from process_madvise() by directly doing the mmap locking first, and then the remaining works for all ranges in the loop. Reviewed-by: Shakeel Butt Signed-off-by: SeongJae Park Reviewed-by: Liam R. Howlett Reviewed-by: Lorenzo Stoakes --- mm/madvise.c | 26 ++++++++++++++++++++++++-- 1 file changed, 24 insertions(+), 2 deletions(-) diff --git a/mm/madvise.c b/mm/madvise.c index 31e5df75b926..5a0a1fc99d27 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -1754,9 +1754,26 @@ static ssize_t vector_madvise(struct mm_struct *mm, = struct iov_iter *iter, =20 total_len =3D iov_iter_count(iter); =20 + ret =3D madvise_lock(mm, behavior); + if (ret) + return ret; + while (iov_iter_count(iter)) { - ret =3D do_madvise(mm, (unsigned long)iter_iov_addr(iter), - iter_iov_len(iter), behavior); + unsigned long start =3D (unsigned long)iter_iov_addr(iter); + size_t len_in =3D iter_iov_len(iter); + size_t len; + + if (!is_valid_madvise(start, len_in, behavior)) { + ret =3D -EINVAL; + break; + } + + len =3D PAGE_ALIGN(len_in); + if (start + len =3D=3D start) + ret =3D 0; + else + ret =3D madvise_do_behavior(mm, start, len_in, len, + behavior); /* * An madvise operation is attempting to restart the syscall, * but we cannot proceed as it would not be correct to repeat @@ -1772,12 +1789,17 @@ static ssize_t vector_madvise(struct mm_struct *mm,= struct iov_iter *iter, ret =3D -EINTR; break; } + + /* Drop and reacquire lock to unwind race. */ + madvise_unlock(mm, behavior); + madvise_lock(mm, behavior); continue; } if (ret < 0) break; iov_iter_advance(iter, iter_iov_len(iter)); } + madvise_unlock(mm, behavior); =20 ret =3D (total_len - iov_iter_count(iter)) ? : ret; =20 --=20 2.39.5