From: Andrew Morton <akpm@linux-foundation.org>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Michal Hocko <mhocko@kernel.org>, Hugh Dickins <hughd@google.com>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
"Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Davidlohr Bueso <dave@stgolabs.net>,
Alexander Viro <viro@zeniv.linux.org.uk>,
stable@vger.kernel.org
Subject: Re: [PATCH] hugetlbfs: dirty pages as they are added to pagecache
Date: Thu, 18 Oct 2018 18:47:26 -0700 [thread overview]
Message-ID: <20181018184726.fb8da5c733da5e0c6a235101@linux-foundation.org> (raw)
In-Reply-To: <20181019004621.GA30067@redhat.com>
On Thu, 18 Oct 2018 20:46:21 -0400 Andrea Arcangeli <aarcange@redhat.com> wrote:
> On Thu, Oct 18, 2018 at 04:16:40PM -0700, Mike Kravetz wrote:
> > I was not sure about this, and expected someone could come up with
> > something better. It just seems there are filesystems like huegtlbfs,
> > where it makes no sense wasting cycles traversing the filesystem. So,
> > let's not even try.
> >
> > Hoping someone can come up with a better method than hard coding as
> > I have done above.
>
> It's not strictly required after marking the pages dirty though. The
> real fix is the other one? Could we just drop the hardcoding and let
> it run after the real fix is applied?
>
> The performance of drop_caches doesn't seem critical, especially with
> gigapages. tmpfs doesn't seem to be optimized away from drop_caches
> and the gain would be bigger for tmpfs if THP is not enabled in the
> mount, so I'm not sure if we should worry about hugetlbfs first.
I guess so. I can't immediately see a clean way of expressing this so
perhaps it would need a new BDI_CAP_NO_BACKING_STORE. Such a
thing hardly seems worthwhile for drop_caches.
And drop_caches really shouldn't be there anyway. It's a standing
workaround for ongoing suckage in pagecache and metadata reclaim
behaviour :(
next prev parent reply other threads:[~2018-10-19 1:47 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-18 4:10 [PATCH] hugetlbfs: dirty pages as they are added to pagecache Mike Kravetz
2018-10-18 23:08 ` Andrew Morton
2018-10-18 23:16 ` Mike Kravetz
2018-10-19 0:46 ` Andrea Arcangeli
2018-10-19 1:47 ` Andrew Morton [this message]
2018-10-19 4:50 ` Mike Kravetz
2018-10-23 7:43 ` Michal Hocko
2018-10-23 17:30 ` Mike Kravetz
2018-10-23 17:41 ` Michal Hocko
2018-10-24 5:00 ` Khalid Aziz
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