Messages in this thread | | | From | Naoya Horiguchi <> | Subject | Re: [PATCH] Hugetlb pages rss accounting is incorrect in /proc/<pid>/smaps | Date | Wed, 25 Oct 2017 22:45:10 +0000 |
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On Wed, Oct 25, 2017 at 08:55:27AM +0200, Michal Hocko wrote: > [CCing Naoya] > > On Tue 24-10-17 16:56:08, Prakash Sangappa wrote: > > Resident set size(Rss) accounting of hugetlb pages is not done > > currently in /proc/<pid>/smaps. The pmap command reads rss from > > this file and so it shows Rss to be 0 in pmap -x output for > > hugetlb mapped vmas. This patch fixes it. > > We do not account in rss because we do have a dedicated counters > depending on whether the hugetlb page is mapped privately or it is > shared. The reason this is not in RSS IIRC is that a large unexpected > RSS from hugetlb pages might confuse system monitors.
Yes, that was the intention of separate counters for hugetlb.
> This is one of > those backward compatibility issues when you start accounting something > too late.
So new monitoring applications are supposed to check the new counters to track hugetlb usages.
Thanks, Naoya Horiguchi
> > > Signed-off-by: Prakash Sangappa <prakash.sangappa@oracle.com> > > --- > > fs/proc/task_mmu.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > > index 5589b4b..c7e1048 100644 > > --- a/fs/proc/task_mmu.c > > +++ b/fs/proc/task_mmu.c > > @@ -724,6 +724,7 @@ static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask, > > mss->shared_hugetlb += huge_page_size(hstate_vma(vma)); > > else > > mss->private_hugetlb += huge_page_size(hstate_vma(vma)); > > + mss->resident += huge_page_size(hstate_vma(vma)); > > } > > return 0; > > } > > -- > > 2.7.4 > > > > -- > Michal Hocko > SUSE Labs > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
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