From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: Eric Biggers <ebiggers@kernel.org>
Cc: linux-fscrypt@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-ext4@vger.kernel.org, Victor Hsieh <victorhsieh@google.com>,
linux-f2fs-devel@lists.sourceforge.net
Subject: Re: [PATCH v2] fs-verity: implement readahead of Merkle tree pages
Date: Mon, 13 Jan 2020 19:14:07 -0500 [thread overview]
Message-ID: <20200114001407.GO76141@mit.edu> (raw)
In-Reply-To: <20200106205533.137005-1-ebiggers@kernel.org>
On Mon, Jan 06, 2020 at 12:55:33PM -0800, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
>
> When fs-verity verifies data pages, currently it reads each Merkle tree
> page synchronously using read_mapping_page().
>
> Therefore, when the Merkle tree pages aren't already cached, fs-verity
> causes an extra 4 KiB I/O request for every 512 KiB of data (assuming
> that the Merkle tree uses SHA-256 and 4 KiB blocks). This results in
> more I/O requests and performance loss than is strictly necessary.
>
> Therefore, implement readahead of the Merkle tree pages.
Looks good. Feel free to add:
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
(for the ext4 and fs/verity bits)
WARNING: multiple messages have this Message-ID (diff)
From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: Eric Biggers <ebiggers@kernel.org>
Cc: linux-fsdevel@vger.kernel.org, linux-fscrypt@vger.kernel.org,
linux-ext4@vger.kernel.org, Victor Hsieh <victorhsieh@google.com>,
linux-f2fs-devel@lists.sourceforge.net
Subject: Re: [f2fs-dev] [PATCH v2] fs-verity: implement readahead of Merkle tree pages
Date: Mon, 13 Jan 2020 19:14:07 -0500 [thread overview]
Message-ID: <20200114001407.GO76141@mit.edu> (raw)
In-Reply-To: <20200106205533.137005-1-ebiggers@kernel.org>
On Mon, Jan 06, 2020 at 12:55:33PM -0800, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
>
> When fs-verity verifies data pages, currently it reads each Merkle tree
> page synchronously using read_mapping_page().
>
> Therefore, when the Merkle tree pages aren't already cached, fs-verity
> causes an extra 4 KiB I/O request for every 512 KiB of data (assuming
> that the Merkle tree uses SHA-256 and 4 KiB blocks). This results in
> more I/O requests and performance loss than is strictly necessary.
>
> Therefore, implement readahead of the Merkle tree pages.
Looks good. Feel free to add:
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
(for the ext4 and fs/verity bits)
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next prev parent reply other threads:[~2020-01-14 0:14 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-06 20:55 [PATCH v2] fs-verity: implement readahead of Merkle tree pages Eric Biggers
2020-01-06 20:55 ` [f2fs-dev] " Eric Biggers
2020-01-13 19:25 ` Eric Biggers
2020-01-13 19:25 ` [f2fs-dev] " Eric Biggers
2020-01-14 0:14 ` Theodore Y. Ts'o [this message]
2020-01-14 0:14 ` Theodore Y. Ts'o
2020-01-14 21:31 ` Eric Biggers
2020-01-14 21:31 ` Eric Biggers
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