On Mon, Jan 05, 2015 at 03:20:37PM -0800, Andrew Morton wrote: > On Mon, 5 Jan 2015 17:55:05 -0500 Rafael Aquini <aqu...@redhat.com> wrote: > > > On Mon, Jan 05, 2015 at 01:35:00PM -0800, Andrew Morton wrote: > > > On Mon, 5 Jan 2015 12:44:31 -0500 Rafael Aquini <aqu...@redhat.com> > > > wrote: > > > > > > > This patch introduces 'kernelpagesize_kB' line element to > > > > /proc/<pid>/numa_maps > > > > report file in order to help identifying the size of pages that are > > > > backing > > > > memory areas mapped by a given task. This is specially useful to > > > > help differentiating between HUGE and GIGANTIC page backed VMAs. > > > > > > > > This patch is based on Dave Hansen's proposal and reviewer's follow-ups > > > > taken from the following dicussion threads: > > > > * https://lkml.org/lkml/2011/9/21/454 > > > > > > Dave's changelog contains useful information which this one lacked. I > > > stole some of it. > > > > > > : The output of /proc/$pid/numa_maps is in terms of number of pages like > > > : anon=22 or dirty=54. Here's some output: > > > : > > > : 7f4680000000 default file=/hugetlb/bigfile anon=50 dirty=50 N0=50 > > > : 7f7659600000 default file=/anon_hugepage\040(deleted) anon=50 dirty=50 > > > N0=50 > > > : 7fff8d425000 default stack anon=50 dirty=50 N0=50 > > > : Looks like we have a stack and a couple of anonymous hugetlbfs > > > : areas page which both use the same amount of memory. They don't. > > > : > > > : The 'bigfile' uses 1GB pages and takes up ~50GB of space. The > > > : anon_hugepage uses 2MB pages and takes up ~100MB of space while the > > > stack > > > : uses normal 4k pages. You can go over to smaps to figure out what the > > > : page size _really_ is with KernelPageSize or MMUPageSize. But, I think > > > : this is a pretty nasty and counterintuitive interface as it stands. > > > : > > > : This patch introduces 'kernelpagesize_kB' line element to > > > : /proc/<pid>/numa_maps report file in order to help identifying the size > > > of > > > : pages that are backing memory areas mapped by a given task. This is > > > : specially useful to help differentiating between HUGE and GIGANTIC page > > > : backed VMAs. > > > : > > > : This patch is based on Dave Hansen's proposal and reviewer's follow-ups > > > : taken from the following dicussion threads: > > > : * https://lkml.org/lkml/2011/9/21/454 > > > : * https://lkml.org/lkml/2014/12/20/66 > > > > > > > > > > + seq_printf(m, " kernelpagesize_kB=%lu", > > > > vma_kernel_pagesize(vma) >> 10); > > > > > > This changes the format of the numa_maps file and can potentially break > > > existing parsers. Please discuss. > > ^^ ?? > Sorry I overlooked it.
Parsers indeed would have to be adjusted to cope with an extra line element (they already have to do so, similarly, for the conditional 'huge' hint). Despite I don't think of it as a showstopper (as is), I think we can consider moving it to EOL, if its actual printout position turns out to be an issue. For instance, with this patch a numa_maps line would look like the following: 7ff965200000 default file=/anon_hugepage\040(deleted) huge kernelpagesize_kB=2048 anon=5 dirty=5 N0=5 or it could look like this, if we decide to switch kernelpagesize_kB position to EOL, for the sake of parsers: 7ff965200000 default file=/anon_hugepage\040(deleted) huge anon=5 dirty=5 N0=5 kernelpagesize_kB=2048 Cheers, -- Rafael -- 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/
