Date: Mon, 21 Mar 2016 19:34:04 +0300
From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Christoph Lameter <cl@linux.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Matthew Wilcox <willy@linux.intel.com>,
        Hugh Dickins <hughd@google.com>, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 0/3] fs, mm: get rid of PAGE_CACHE_* and
 page_cache_{get,release} macros
Message-ID: <20160321163404.GA141069@black.fi.intel.com>
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On Mon, Mar 21, 2016 at 11:25:09AM -0500, Christoph Lameter wrote:
> On Mon, 21 Mar 2016, Kirill A. Shutemov wrote:
> 
> > PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago
> > with promise that one day it will be possible to implement page cache with
> > bigger chunks than PAGE_SIZE.
> >
> > This promise never materialized. And unlikely will.
> 
> So we decided that we are never going to put THP pages on a LRU?

Err?.. What?

We do have anon-THP pages on LRU. My huge tmpfs patchset also put
file-THPs on LRU list.

The patchset has nothing to do with THP or them being on LRU.

> Will this actually work if we have really huge memory (100s of TB) where
> almost everything is a huge page? Guess we have to use hugetlbfs and we
> need to think about this as being exempt from paging.

Sorry, I failed to understand your message.

Look on huge tmpfs patchset. It allows both small and huge pages in page
cache.

Anyway, it's out of scope of the patchset.

-- 
 Kirill A. Shutemov