On Wed, Feb 27, 2019 at 07:36:50PM +0100, David Sterba wrote: > On Wed, Feb 27, 2019 at 01:29:16PM -0500, Dennis Zhou wrote: > > > I've noticed while reading the code, why do you use the indirect call > > > here? The wsm.ops points to btrfs_zstd_compress so free_workspace is > > > always zstd_free_workspace. > > > > > > The compiler is usually smart to replace such things by direct call if > > > the type has not escaped, but this is not true for btrfs_compress_op so > > > the indirect function call must be preserved. > > > > I don't have a strong reason to use the indirect call here. It was just > > to make it consistent for everyone to use the indirection. This at least > > is in the cleanup path, so I don't think performance is that important? > > It's not just that, the timer uses it too and there are indirect calls > of the alloc_workspace callback. The indirection is not used by lzo nor > zlib code, so I don't see what 'everyone' you mean. In the generic > compression code it makes sense, I see that. > > > But I don't feel strongly for or against calling zstd_free_workspace() > > directly. > > I feel strongly about not using the indirection when not necessary :)
Great :). I sent you a patch just now to remove the indirection [1]. [1] https://lore.kernel.org/linux-btrfs/20190227212128.38491-1-den...@kernel.org Thanks, Dennis
