On Mon, Aug 08, 2022 at 02:42:03PM -0400, Kent Overstreet wrote: > On 8/8/22 13:51, Bjorn Helgaas wrote: > > I don't object to the patch, but it would be nice if the commit log > > hinted at what the advantage is. I assume it's faster/safer/better in > > some way, but I have no idea what. > > Printbufs have some additional features over seq_buf but they're not used > here. The main one you might be interested in is heap allocation: that means > no need to statically allocate buffers on the stack and no need to calculate > the buffer size, printbufs will reallocate as necessary. This doesn't tell me what the advantage of this patch is, since I don't think *this* patch uses heap allocation. As far as I can tell, this particular patch doesn't improve safety or readability, so "convert X to Y even though we don't use any fancy Y features" is a pointless message. But if printbufs are better than seq_buf overall, and converting this gets us closer to the goal of removing seq_buf completely, that's a perfectly acceptable reason. Just say that. > I generally haven't been converting code to use that unless it's obvious > that we're in a context where it's safe to allocate memory and can deal with > allocation failures. > > I notice that in calc_map_type_and_dist() you're using xa_store() which can > fail, but you're not checking for that or returning errors properly :) > perhaps a fix for that could also switch to using printbuf in > heap-allocation mode. > > > Also, cpu_show_meltdown() doesn't appear in this patch, so maybe > > that's relevant to some other patch but not this one? > > Whoops, was copying the commit message from another patch, yeah.n
