On Sat, 2014-02-15 at 02:06 -0800, David Rientjes wrote: > On Fri, 14 Feb 2014, Luiz Capitulino wrote: > > > > Again, I think this syntax is horrendous and doesn't couple well with the > > > other hugepage-related kernel command line options. We already have > > > hugepages= and hugepagesz= which you can interleave on the command line > > > to > > > get 100 2M hugepages and 10 1GB hugepages, for example. > > > > > > This patchset is simply introducing another variable to the matter: the > > > node that the hugepages should be allocated on. So just introduce a > > > hugepagesnode= parameter to couple with the others so you can do > > > > > > hugepagesz=<size> hugepagesnode=<nid> hugepages=<#> > > > > That was my first try but it turned out really bad. First, for every node > > you specify you need three options. > > Just like you need two options today to specify a number of hugepages of a > particular non-default size. You only need to use hugepagesz= or > hugepagenode= if you want a non-default size or a specify a particular > node. > > > So, if you want to setup memory for > > three nodes you'll need to specify nine options. > > And you currently need six if you want to specify three different hugepage > sizes (?). But who really specifies three different hugepage sizes on the > command line that are needed to be reserved at boot? > > If that's really the usecase, it seems like you want the old > CONFIG_PAGE_SHIFT patch. > > > And it gets worse, because > > hugepagesz= and hugepages= have strict ordering (which is a mistake, IMHO) > > so > > you have to specify them in the right order otherwise things don't work as > > expected and you have no idea why (have been there myself). > > > > How is that difficult? hugepages= is the "noun", hugepagesz= is the > "adjective". hugepages=100 hugepagesz=1G hugepages=4 makes perfect sense > to me, and I actually don't allocate hugepages on the command line, nor > have I looked at Documentation/kernel-parameters.txt to check if I'm > constructing it correctly. It just makes sense and once you learn it it's > just natural.
This can get annoying _really_ fast for larger systems. > > IMO, hugepages_node=<nid>:<nr_pages>:<size>,... is good enough. It's > > concise, > > and don't depend on any other option to function. Also, there are lots of > > other > > kernel command-line options that require you to specify multiple fields, so > > it's not like hugepages_node= is totally different in that regard. > > Agreed. > > I doubt Andrew is going to want a completely different format for hugepage > allocations that want to specify a node and have to deal with people who > say hugepages_node=2:1:1G and constantly have to lookup if it's 2 > hugepages on node 1 or 1 hugepage on node 2. I guess most users won't even be aware of this new parameter and those who really care will have the choice. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
