From: Andrew Morton <akpm@linux-foundation.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: "Andrey Ryabinin" <aryabinin@virtuozzo.com>,
linux-mm@kvack.org, "Matthew Wilcox" <mawilcox@microsoft.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
"Christoph Lameter" <cl@linux.com>,
"Lai Jiangshan" <jiangshanlai@gmail.com>,
"Pekka Enberg" <penberg@kernel.org>,
"Vlastimil Babka" <vbabka@suse.cz>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"Jérôme Glisse" <jglisse@redhat.com>
Subject: Re: [PATCH v6 17/17] mm: Distinguish VMalloc pages
Date: Tue, 22 May 2018 16:02:34 -0700 [thread overview]
Message-ID: <20180522160234.a1fc9de7626de52cfb3a2e7d@linux-foundation.org> (raw)
In-Reply-To: <20180522214517.GA30913@bombadil.infradead.org>
On Tue, 22 May 2018 14:45:17 -0700 Matthew Wilcox <willy@infradead.org> wrote:
> On Tue, May 22, 2018 at 01:48:38PM -0700, Andrew Morton wrote:
> > -ENOCOMMENT ;)
> >
> > --- a/mm/util.c~mm-distinguish-vmalloc-pages-fix-fix
> > +++ a/mm/util.c
> > @@ -512,6 +512,8 @@ struct address_space *page_mapping(struc
> > mapping = page->mapping;
> > if ((unsigned long)mapping & PAGE_MAPPING_ANON)
> > return NULL;
> > +
> > + /* Don't trip over a vmalloc page's MAPPING_VMalloc cookie */
> > if ((unsigned long)mapping < PAGE_SIZE)
> > return NULL;
> >
> > It's a bit sad to put even more stuff into page_mapping() just for
> > page_types diddling. Is this really justified? How many people will
> > use it, and get significant benefit from it?
>
> We could leave page->mapping NULL for vmalloc pages. We just need to
> find a spot where we can put a unique identifier. The first word of
> the union looks like a string candidate; bit 0 is already reserved for
> PageTail. The other users are list_head.prev, a struct page *, and
> struct dev_pagemap *, so that should work out OK.
>
> If you want to just drop this patch, I'd be OK with that. I can always
> submit it to you again next merge window.
OK, let's park it for now.
next prev parent reply other threads:[~2018-05-22 23:02 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-18 19:45 [PATCH v6 00/17] Rearrange struct page Matthew Wilcox
2018-05-18 19:45 ` [PATCH v6 01/17] s390: Use _refcount for pgtables Matthew Wilcox
2018-05-18 19:45 ` [PATCH v6 02/17] mm: Split page_type out from _mapcount Matthew Wilcox
2018-05-18 19:45 ` [PATCH v6 03/17] mm: Mark pages in use for page tables Matthew Wilcox
2018-05-18 19:45 ` [PATCH v6 04/17] mm: Switch s_mem and slab_cache in struct page Matthew Wilcox
2018-05-18 19:45 ` [PATCH v6 05/17] mm: Move 'private' union within " Matthew Wilcox
2018-05-18 19:45 ` [PATCH v6 06/17] mm: Move _refcount out of struct page union Matthew Wilcox
2018-05-18 19:45 ` [PATCH v6 07/17] mm: Combine first three unions in struct page Matthew Wilcox
2018-05-18 19:45 ` [PATCH v6 08/17] mm: Use page->deferred_list Matthew Wilcox
2018-05-18 19:45 ` [PATCH v6 09/17] mm: Move lru union within struct page Matthew Wilcox
2018-05-18 19:45 ` [PATCH v6 10/17] mm: Combine LRU and main union in " Matthew Wilcox
2018-05-18 19:45 ` [PATCH v6 11/17] mm: Improve struct page documentation Matthew Wilcox
2018-05-18 19:45 ` [PATCH v6 12/17] mm: Add pt_mm to struct page Matthew Wilcox
2018-05-18 19:45 ` [PATCH v6 13/17] mm: Add hmm_data " Matthew Wilcox
2018-05-18 19:45 ` [PATCH v6 14/17] slab,slub: Remove rcu_head size checks Matthew Wilcox
2018-05-18 19:45 ` [PATCH v6 15/17] slub: Remove kmem_cache->reserved Matthew Wilcox
2018-05-18 19:45 ` [PATCH v6 16/17] slub: Remove 'reserved' file from sysfs Matthew Wilcox
2018-05-18 19:45 ` [PATCH v6 17/17] mm: Distinguish VMalloc pages Matthew Wilcox
2018-05-22 16:10 ` Andrey Ryabinin
2018-05-22 17:58 ` Matthew Wilcox
2018-05-22 19:49 ` Andrew Morton
2018-05-22 19:57 ` Andrey Ryabinin
2018-05-22 20:19 ` Matthew Wilcox
2018-05-22 20:48 ` Andrew Morton
2018-05-22 21:45 ` Matthew Wilcox
2018-05-22 23:02 ` Andrew Morton [this message]
2018-05-23 6:36 ` Michal Hocko
2018-05-23 6:34 ` Michal Hocko
2018-05-23 9:14 ` Andrey Ryabinin
2018-05-23 9:25 ` Michal Hocko
2018-05-23 9:28 ` Andrey Ryabinin
2018-05-23 9:52 ` Michal Hocko
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