On Thu, Nov 10, 2016 at 2:11 PM, Dan Williams <dan.j.willi...@intel.com> wrote: > ZONE_DEVICE pages are mapped into a process via the filesystem-dax and > device-dax mechanisms. There are also proposals to use ZONE_DEVICE > pages for other usages outside of dax. Add statistics to smaps so > applications can debug that they are obtaining the mappings they expect, > or otherwise accounting them. > > Cc: Christoph Hellwig <h...@lst.de>
Christoph, Wanted to get your opinion on this given your earlier concerns about the VM_DAX flag. This instead lets an application know how much of a vma is backed by ZONE_DEVICE pages, but does not make any indications about the vma having DAX semantics or not. I.e. it is possible that 'device' and 'device_huge' are non-zero *and* vma_is_dax() is false. So, it is purely accounting the composition of the present pages in the vma. Another option is to have something like 'shared_thp' just to account for file backed huge pages that dax can map. However if ZONE_DEVICE is leaking into other use cases I think it makes sense to have it be a first class-citizen with respect to accounting alongside 'anonymous_thp'. > Cc: Dave Hansen <dave.han...@intel.com> > Cc: Andrew Morton <a...@linux-foundation.org> > Signed-off-by: Dan Williams <dan.j.willi...@intel.com> > --- > fs/proc/task_mmu.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > index 35b92d81692f..6765cafcf057 100644 > --- a/fs/proc/task_mmu.c > +++ b/fs/proc/task_mmu.c > @@ -445,6 +445,8 @@ struct mem_size_stats { > unsigned long swap; > unsigned long shared_hugetlb; > unsigned long private_hugetlb; > + unsigned long device; > + unsigned long device_huge; > u64 pss; > u64 swap_pss; > bool check_shmem_swap; > @@ -458,6 +460,8 @@ static void smaps_account(struct mem_size_stats *mss, > struct page *page, > > if (PageAnon(page)) > mss->anonymous += size; > + else if (is_zone_device_page(page)) > + mss->device += size; > > mss->resident += size; > /* Accumulate the size in pages that have been accessed. */ > @@ -575,7 +579,7 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long > addr, > else if (PageSwapBacked(page)) > mss->shmem_thp += HPAGE_PMD_SIZE; > else if (is_zone_device_page(page)) > - /* pass */; > + mss->device_huge += HPAGE_PMD_SIZE; > else > VM_BUG_ON_PAGE(1, page); > smaps_account(mss, page, true, pmd_young(*pmd), pmd_dirty(*pmd)); > @@ -774,6 +778,8 @@ static int show_smap(struct seq_file *m, void *v, int > is_pid) > "ShmemPmdMapped: %8lu kB\n" > "Shared_Hugetlb: %8lu kB\n" > "Private_Hugetlb: %7lu kB\n" > + "Device: %8lu kB\n" > + "DeviceHugePages: %7lu kB\n" > "Swap: %8lu kB\n" > "SwapPss: %8lu kB\n" > "KernelPageSize: %8lu kB\n" > @@ -792,6 +798,8 @@ static int show_smap(struct seq_file *m, void *v, int > is_pid) > mss.shmem_thp >> 10, > mss.shared_hugetlb >> 10, > mss.private_hugetlb >> 10, > + mss.device >> 10, > + mss.device_huge >> 10, > mss.swap >> 10, > (unsigned long)(mss.swap_pss >> (10 + PSS_SHIFT)), > vma_kernel_pagesize(vma) >> 10, > _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm