From: Alexander Duyck <alexander.h.duyck@linux.intel.com>
To: linux-mm@kvack.org, akpm@linux-foundation.org
Cc: pavel.tatashin@microsoft.com, mhocko@suse.com,
dave.jiang@intel.com, alexander.h.duyck@linux.intel.com,
linux-kernel@vger.kernel.org, willy@infradead.org,
davem@davemloft.net, yi.z.zhang@linux.intel.com,
khalid.aziz@oracle.com, rppt@linux.vnet.ibm.com, vbabka@suse.cz,
sparclinux@vger.kernel.org, dan.j.williams@intel.com,
ldufour@linux.vnet.ibm.com, mgorman@techsingularity.net,
mingo@kernel.org, kirill.shutemov@linux.intel.com
Subject: [mm PATCH v2 1/6] mm: Use mm_zero_struct_page from SPARC on all 64b architectures
Date: Thu, 11 Oct 2018 15:13:34 -0700 [thread overview]
Message-ID: <20181011221334.1925.31961.stgit@localhost.localdomain> (raw)
In-Reply-To: <20181011221237.1925.85591.stgit@localhost.localdomain>
This change makes it so that we use the same approach that was already in
use on Sparc on all the archtectures that support a 64b long.
This is mostly motivated by the fact that 8 to 10 store/move instructions
are likely always going to be faster than having to call into a function
that is not specialized for handling page init.
An added advantage to doing it this way is that the compiler can get away
with combining writes in the __init_single_page call. As a result the
memset call will be reduced to only about 4 write operations, or at least
that is what I am seeing with GCC 6.2 as the flags, LRU poitners, and
count/mapcount seem to be cancelling out at least 4 of the 8 assignments on
my system.
One change I had to make to the function was to reduce the minimum page
size to 56 to support some powerpc64 configurations.
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
---
arch/sparc/include/asm/pgtable_64.h | 30 ------------------------------
include/linux/mm.h | 34 ++++++++++++++++++++++++++++++++++
2 files changed, 34 insertions(+), 30 deletions(-)
diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
index 1393a8ac596b..22500c3be7a9 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -231,36 +231,6 @@
extern struct page *mem_map_zero;
#define ZERO_PAGE(vaddr) (mem_map_zero)
-/* This macro must be updated when the size of struct page grows above 80
- * or reduces below 64.
- * The idea that compiler optimizes out switch() statement, and only
- * leaves clrx instructions
- */
-#define mm_zero_struct_page(pp) do { \
- unsigned long *_pp = (void *)(pp); \
- \
- /* Check that struct page is either 64, 72, or 80 bytes */ \
- BUILD_BUG_ON(sizeof(struct page) & 7); \
- BUILD_BUG_ON(sizeof(struct page) < 64); \
- BUILD_BUG_ON(sizeof(struct page) > 80); \
- \
- switch (sizeof(struct page)) { \
- case 80: \
- _pp[9] = 0; /* fallthrough */ \
- case 72: \
- _pp[8] = 0; /* fallthrough */ \
- default: \
- _pp[7] = 0; \
- _pp[6] = 0; \
- _pp[5] = 0; \
- _pp[4] = 0; \
- _pp[3] = 0; \
- _pp[2] = 0; \
- _pp[1] = 0; \
- _pp[0] = 0; \
- } \
-} while (0)
-
/* PFNs are real physical page numbers. However, mem_map only begins to record
* per-page information starting at pfn_base. This is to handle systems where
* the first physical page in the machine is at some huge physical address,
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 273d4dbd3883..dee407998366 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -102,8 +102,42 @@ static inline void set_max_mapnr(unsigned long limit) { }
* zeroing by defining this macro in <asm/pgtable.h>.
*/
#ifndef mm_zero_struct_page
+#if BITS_PER_LONG == 64
+/* This function must be updated when the size of struct page grows above 80
+ * or reduces below 64. The idea that compiler optimizes out switch()
+ * statement, and only leaves move/store instructions
+ */
+#define mm_zero_struct_page(pp) __mm_zero_struct_page(pp)
+static inline void __mm_zero_struct_page(struct page *page)
+{
+ unsigned long *_pp = (void *)page;
+
+ /* Check that struct page is either 56, 64, 72, or 80 bytes */
+ BUILD_BUG_ON(sizeof(struct page) & 7);
+ BUILD_BUG_ON(sizeof(struct page) < 56);
+ BUILD_BUG_ON(sizeof(struct page) > 80);
+
+ switch (sizeof(struct page)) {
+ case 80:
+ _pp[9] = 0; /* fallthrough */
+ case 72:
+ _pp[8] = 0; /* fallthrough */
+ default:
+ _pp[7] = 0; /* fallthrough */
+ case 56:
+ _pp[6] = 0;
+ _pp[5] = 0;
+ _pp[4] = 0;
+ _pp[3] = 0;
+ _pp[2] = 0;
+ _pp[1] = 0;
+ _pp[0] = 0;
+ }
+}
+#else
#define mm_zero_struct_page(pp) ((void)memset((pp), 0, sizeof(struct page)))
#endif
+#endif
/*
* Default maximum number of active map areas, this limits the number of vmas
next prev parent reply other threads:[~2018-10-11 22:16 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-11 22:13 [mm PATCH v2 0/6] Deferred page init improvements Alexander Duyck
2018-10-11 22:13 ` Alexander Duyck [this message]
2018-10-13 16:58 ` [mm PATCH v2 1/6] mm: Use mm_zero_struct_page from SPARC on all 64b architectures Pavel Tatashin
2018-10-13 17:18 ` Alexander Duyck
2018-10-13 17:49 ` Pavel Tatashin
2018-10-13 18:46 ` Alexander Duyck
2018-10-11 22:13 ` [mm PATCH v2 2/6] mm: Drop meminit_pfn_in_nid as it is redundant Alexander Duyck
2018-10-11 22:13 ` [mm PATCH v2 3/6] mm: Use memblock/zone specific iterator for handling deferred page init Alexander Duyck
2018-10-11 22:13 ` [mm PATCH v2 4/6] mm: Do not set reserved flag for hotplug memory Alexander Duyck
2018-10-11 22:58 ` Dan Williams
2018-10-11 23:22 ` Alexander Duyck
2018-10-11 22:13 ` [mm PATCH v2 5/6] mm: Move hot-plug specific memory init into separate functions and optimize Alexander Duyck
2018-10-11 22:14 ` [mm PATCH v2 6/6] mm: Use common iterator for deferred_init_pages and deferred_free_pages Alexander Duyck
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20181011221334.1925.31961.stgit@localhost.localdomain \
--to=alexander.h.duyck@linux.intel.com \
--cc=akpm@linux-foundation.org \
--cc=dan.j.williams@intel.com \
--cc=dave.jiang@intel.com \
--cc=davem@davemloft.net \
--cc=khalid.aziz@oracle.com \
--cc=kirill.shutemov@linux.intel.com \
--cc=ldufour@linux.vnet.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@techsingularity.net \
--cc=mhocko@suse.com \
--cc=mingo@kernel.org \
--cc=pavel.tatashin@microsoft.com \
--cc=rppt@linux.vnet.ibm.com \
--cc=sparclinux@vger.kernel.org \
--cc=vbabka@suse.cz \
--cc=willy@infradead.org \
--cc=yi.z.zhang@linux.intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).