From: Matthew Wilcox <willy@infradead.org>
To: Christopher Lameter <cl@linux.com>
Cc: linux-mm@kvack.org, Matthew Wilcox <mawilcox@microsoft.com>,
Andrew Morton <akpm@linux-foundation.org>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Lai Jiangshan <laijs@cn.fujitsu.com>,
Pekka Enberg <penberg@kernel.org>,
Vlastimil Babka <vbabka@suse.cz>
Subject: Re: [PATCH v3 05/14] mm: Move 'private' union within struct page
Date: Fri, 20 Apr 2018 13:27:37 -0700 [thread overview]
Message-ID: <20180420202737.GE10788@bombadil.infradead.org> (raw)
In-Reply-To: <alpine.DEB.2.20.1804201024090.18006@nuc-kabylake>
On Fri, Apr 20, 2018 at 10:25:14AM -0500, Christopher Lameter wrote:
> On Wed, 18 Apr 2018, Matthew Wilcox wrote:
> > + union {
> > + unsigned long private;
> > +#if USE_SPLIT_PTE_PTLOCKS
> > +#if ALLOC_SPLIT_PTLOCKS
> > + spinlock_t *ptl;
> > +#else
> > + spinlock_t ptl;
>
> ^^^^ This used to be defined at the end of the struct so that you could
> have larger structs for spinlocks here (debugging and some such thing).
>
> Could this not misalign the rest?
Nope:
include/linux/mm_types_task.h:#define ALLOC_SPLIT_PTLOCKS (SPINLOCK_SIZE > BITS_PER_LONG/8)
So we'll only store a spinlock here if it's <= sizeof(long); otherwise
we'll store a pointer here.
next prev parent reply other threads:[~2018-04-20 20:27 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-18 18:48 [PATCH v3 00/14] Rearrange struct page Matthew Wilcox
2018-04-18 18:48 ` [PATCH v3 01/14] s390: Use _refcount for pgtables Matthew Wilcox
2018-04-18 18:49 ` [PATCH v3 02/14] mm: Split page_type out from _mapcount Matthew Wilcox
2018-04-19 9:04 ` Vlastimil Babka
2018-04-19 11:16 ` Matthew Wilcox
2018-04-20 15:17 ` Christopher Lameter
2018-04-20 20:43 ` Matthew Wilcox
2018-04-18 18:49 ` [PATCH v3 03/14] mm: Mark pages in use for page tables Matthew Wilcox
2018-04-19 9:30 ` Vlastimil Babka
2018-04-18 18:49 ` [PATCH v3 04/14] mm: Switch s_mem and slab_cache in struct page Matthew Wilcox
2018-04-19 11:06 ` Vlastimil Babka
2018-04-19 11:19 ` Matthew Wilcox
2018-04-18 18:49 ` [PATCH v3 05/14] mm: Move 'private' union within " Matthew Wilcox
2018-04-19 11:31 ` Vlastimil Babka
2018-04-20 15:25 ` Christopher Lameter
2018-04-20 20:27 ` Matthew Wilcox [this message]
2018-04-30 9:38 ` Kirill A. Shutemov
2018-04-18 18:49 ` [PATCH v3 06/14] mm: Move _refcount out of struct page union Matthew Wilcox
2018-04-19 11:37 ` Vlastimil Babka
2018-04-30 9:40 ` Kirill A. Shutemov
2018-04-18 18:49 ` [PATCH v3 07/14] slub: Remove page->counters Matthew Wilcox
2018-04-19 13:42 ` Vlastimil Babka
2018-04-19 14:23 ` Matthew Wilcox
2018-04-18 18:49 ` [PATCH v3 08/14] mm: Combine first three unions in struct page Matthew Wilcox
2018-04-19 13:46 ` Vlastimil Babka
2018-04-19 14:08 ` Matthew Wilcox
2018-04-30 9:42 ` Kirill A. Shutemov
2018-04-18 18:49 ` [PATCH v3 09/14] mm: Use page->deferred_list Matthew Wilcox
2018-04-19 13:23 ` Vlastimil Babka
2018-04-30 9:43 ` Kirill A. Shutemov
2018-04-18 18:49 ` [PATCH v3 10/14] mm: Move lru union within struct page Matthew Wilcox
2018-04-19 13:56 ` Vlastimil Babka
2018-04-30 9:44 ` Kirill A. Shutemov
2018-04-18 18:49 ` [PATCH v3 11/14] mm: Combine first two unions in " Matthew Wilcox
2018-04-19 14:03 ` Vlastimil Babka
2018-04-30 9:47 ` Kirill A. Shutemov
2018-04-30 12:42 ` Matthew Wilcox
2018-04-30 13:12 ` Kirill A. Shutemov
2018-04-18 18:49 ` [PATCH v3 12/14] mm: Improve struct page documentation Matthew Wilcox
2018-04-18 23:32 ` Randy Dunlap
2018-04-18 23:43 ` Matthew Wilcox
2018-04-18 18:49 ` [PATCH v3 13/14] slab,slub: Remove rcu_head size checks Matthew Wilcox
2018-04-18 18:49 ` [PATCH v3 14/14] slub: Remove kmem_cache->reserved Matthew Wilcox
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