Re: [PATCH v11 11/14] btrfs: send: write larger chunks when using stream v2
From: Nikolay Borisov <hidden>
Date: 2021-10-18 12:57:22
Also in:
linux-btrfs, linux-fsdevel
From: Nikolay Borisov <hidden>
Date: 2021-10-18 12:57:22
Also in:
linux-btrfs, linux-fsdevel
On 1.09.21 г. 20:01, Omar Sandoval wrote:
From: Omar Sandoval <redacted> The length field of the send stream TLV header is 16 bits. This means that the maximum amount of data that can be sent for one write is 64k minus one. However, encoded writes must be able to send the maximum compressed extent (128k) in one command. To support this, send stream version 2 encodes the DATA attribute differently: it has no length field, and the length is implicitly up to the end of containing command (which has a 32-bit length field). Although this is necessary for encoded writes, normal writes can benefit from it, too. For v2, let's bump up the send buffer to the maximum compressed extent size plus 16k for the other metadata (144k total). Since this will most likely be vmalloc'd (and always will be after the next commit), we round it up to the next page since we might as well use the rest of the page on systems with >16k pages. Signed-off-by: Omar Sandoval <redacted>
Reviewed-by: Nikolay Borisov <redacted>