From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Andrew Morton <akpm@linux-foundation.org>,
Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>,
Dave Hansen <dave.hansen@intel.com>,
Vlastimil Babka <vbabka@suse.cz>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@suse.cz>,
David Rientjes <rientjes@google.com>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: [PATCHv5 7/7] mm: use 'unsigned int' for compound_dtor/compound_order on 64BIT
Date: Thu, 3 Sep 2015 15:35:58 +0300 [thread overview]
Message-ID: <1441283758-92774-8-git-send-email-kirill.shutemov@linux.intel.com> (raw)
In-Reply-To: <1441283758-92774-1-git-send-email-kirill.shutemov@linux.intel.com>
On 64 bit system we have enough space in struct page to encode
compound_dtor and compound_order with unsigned int.
On x86-64 it leads to slightly smaller code size due usesage of plain
MOV instead of MOVZX (zero-extended move) or similar effect.
allyesconfig:
text data bss dec hex filename
159520446 48146736 72196096 279863278 10ae5fee vmlinux.pre
159520382 48146736 72196096 279863214 10ae5fae vmlinux.post
On other architectures without native support of 16-bit data types the
difference can be bigger.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
---
include/linux/mm_types.h | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index ecaf3b1d0216..39b0db74ba5e 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -150,8 +150,13 @@ struct page {
/* First tail page of compound page */
struct {
unsigned long compound_head; /* If bit zero is set */
+#ifdef CONFIG_64BIT
+ unsigned int compound_dtor;
+ unsigned int compound_order;
+#else
unsigned short int compound_dtor;
unsigned short int compound_order;
+#endif
};
#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS
--
2.5.0
WARNING: multiple messages have this Message-ID (diff)
From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Andrew Morton <akpm@linux-foundation.org>,
Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>,
Dave Hansen <dave.hansen@intel.com>,
Vlastimil Babka <vbabka@suse.cz>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@suse.cz>,
David Rientjes <rientjes@google.com>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: [PATCHv5 7/7] mm: use 'unsigned int' for compound_dtor/compound_order on 64BIT
Date: Thu, 3 Sep 2015 15:35:58 +0300 [thread overview]
Message-ID: <1441283758-92774-8-git-send-email-kirill.shutemov@linux.intel.com> (raw)
In-Reply-To: <1441283758-92774-1-git-send-email-kirill.shutemov@linux.intel.com>
On 64 bit system we have enough space in struct page to encode
compound_dtor and compound_order with unsigned int.
On x86-64 it leads to slightly smaller code size due usesage of plain
MOV instead of MOVZX (zero-extended move) or similar effect.
allyesconfig:
text data bss dec hex filename
159520446 48146736 72196096 279863278 10ae5fee vmlinux.pre
159520382 48146736 72196096 279863214 10ae5fae vmlinux.post
On other architectures without native support of 16-bit data types the
difference can be bigger.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
---
include/linux/mm_types.h | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index ecaf3b1d0216..39b0db74ba5e 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -150,8 +150,13 @@ struct page {
/* First tail page of compound page */
struct {
unsigned long compound_head; /* If bit zero is set */
+#ifdef CONFIG_64BIT
+ unsigned int compound_dtor;
+ unsigned int compound_order;
+#else
unsigned short int compound_dtor;
unsigned short int compound_order;
+#endif
};
#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS
--
2.5.0
--
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next prev parent reply other threads:[~2015-09-03 12:36 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-03 12:35 [PATCHv5 0/7] Fix compound_head() race Kirill A. Shutemov
2015-09-03 12:35 ` Kirill A. Shutemov
2015-09-03 12:35 ` [PATCHv5 1/7] mm: drop page->slab_page Kirill A. Shutemov
2015-09-03 12:35 ` Kirill A. Shutemov
2015-09-07 5:00 ` Alexander Duyck
2015-09-07 5:00 ` Alexander Duyck
2015-09-07 12:19 ` Kirill A. Shutemov
2015-09-07 12:19 ` Kirill A. Shutemov
2015-09-03 12:35 ` [PATCHv5 2/7] slub: use page->rcu_head instead of page->lru plus cast Kirill A. Shutemov
2015-09-03 12:35 ` Kirill A. Shutemov
2015-09-03 12:35 ` [PATCHv5 3/7] zsmalloc: use page->private instead of page->first_page Kirill A. Shutemov
2015-09-03 12:35 ` Kirill A. Shutemov
2015-09-03 12:35 ` [PATCHv5 4/7] mm: pack compound_dtor and compound_order into one word in struct page Kirill A. Shutemov
2015-09-03 12:35 ` Kirill A. Shutemov
2015-09-10 9:41 ` Vlastimil Babka
2015-09-10 9:41 ` Vlastimil Babka
2015-09-03 12:35 ` [PATCHv5 5/7] mm: make compound_head() robust Kirill A. Shutemov
2015-09-03 12:35 ` Kirill A. Shutemov
2015-09-10 10:54 ` Vlastimil Babka
2015-09-10 10:54 ` Vlastimil Babka
2015-09-11 13:35 ` Kirill A. Shutemov
2015-09-11 13:35 ` Kirill A. Shutemov
2015-09-14 13:31 ` Vlastimil Babka
2015-09-14 13:31 ` Vlastimil Babka
2015-09-03 12:35 ` [PATCHv5 6/7] mm: use 'unsigned int' for page order Kirill A. Shutemov
2015-09-03 12:35 ` Kirill A. Shutemov
2015-09-10 11:04 ` Vlastimil Babka
2015-09-10 11:04 ` Vlastimil Babka
2015-09-03 12:35 ` Kirill A. Shutemov [this message]
2015-09-03 12:35 ` [PATCHv5 7/7] mm: use 'unsigned int' for compound_dtor/compound_order on 64BIT Kirill A. Shutemov
2015-09-10 11:34 ` Vlastimil Babka
2015-09-10 11:34 ` Vlastimil Babka
2015-09-04 13:43 ` [PATCHv5 0/7] Fix compound_head() race Andrea Arcangeli
2015-09-04 13:43 ` Andrea Arcangeli
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