From: Alexander Duyck <alexander.h.duyck@linux.intel.com>
To: linux-mm@kvack.org, akpm@linux-foundation.org,
linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org
Cc: pavel.tatashin@microsoft.com, mhocko@suse.com,
dave.jiang@intel.com, dave.hansen@intel.com, jglisse@redhat.com,
rppt@linux.vnet.ibm.com, dan.j.williams@intel.com,
logang@deltatee.com, mingo@kernel.org,
kirill.shutemov@linux.intel.com
Subject: [PATCH v5 3/4] mm: Create non-atomic version of SetPageReserved for init use
Date: Tue, 25 Sep 2018 13:20:47 -0700 [thread overview]
Message-ID: <20180925202018.3576.11607.stgit@localhost.localdomain> (raw)
In-Reply-To: <20180925200551.3576.18755.stgit@localhost.localdomain>
It doesn't make much sense to use the atomic SetPageReserved at init time
when we are using memset to clear the memory and manipulating the page
flags via simple "&=" and "|=" operations in __init_single_page.
This patch adds a non-atomic version __SetPageReserved that can be used
during page init and shows about a 10% improvement in initialization times
on the systems I have available for testing. On those systems I saw
initialization times drop from around 35 seconds to around 32 seconds to
initialize a 3TB block of persistent memory. I believe the main advantage
of this is that it allows for more compiler optimization as the __set_bit
operation can be reordered whereas the atomic version cannot.
I tried adding a bit of documentation based on commit <f1dd2cd13c4> ("mm,
memory_hotplug: do not associate hotadded memory to zones until online").
Ideally the reserved flag should be set earlier since there is a brief
window where the page is initialization via __init_single_page and we have
not set the PG_Reserved flag. I'm leaving that for a future patch set as
that will require a more significant refactor.
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
---
v4: Added comment about __set_bit vs set_bit to the patch description
v5: No change
include/linux/page-flags.h | 1 +
mm/page_alloc.c | 9 +++++++--
2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 934f91ef3f54..50ce1bddaf56 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -303,6 +303,7 @@ static inline void page_init_poison(struct page *page, size_t size)
PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
__CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
+ __SETPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
PAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
__CLEARPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
__SETPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 511447ac02cf..926ad3083b28 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1238,7 +1238,12 @@ void __meminit reserve_bootmem_region(phys_addr_t start, phys_addr_t end)
/* Avoid false-positive PageTail() */
INIT_LIST_HEAD(&page->lru);
- SetPageReserved(page);
+ /*
+ * no need for atomic set_bit because the struct
+ * page is not visible yet so nobody should
+ * access it yet.
+ */
+ __SetPageReserved(page);
}
}
}
@@ -5512,7 +5517,7 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
page = pfn_to_page(pfn);
__init_single_page(page, pfn, zone, nid);
if (context == MEMMAP_HOTPLUG)
- SetPageReserved(page);
+ __SetPageReserved(page);
/*
* Mark the block movable so that blocks are reserved for
next prev parent reply other threads:[~2018-09-25 20:21 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-25 20:18 [PATCH v5 0/4] Address issues slowing persistent memory initialization Alexander Duyck
2018-09-25 20:19 ` [PATCH v5 1/4] mm: Remove now defunct NO_BOOTMEM from depends list for deferred init Alexander Duyck
2018-09-25 21:05 ` Mike Rapoport
2018-09-25 20:20 ` [PATCH v5 2/4] mm: Provide kernel parameter to allow disabling page init poisoning Alexander Duyck
2018-09-25 20:26 ` Dave Hansen
2018-09-25 20:38 ` Alexander Duyck
2018-09-25 22:14 ` Dave Hansen
2018-09-25 22:27 ` Alexander Duyck
2018-09-26 7:38 ` Michal Hocko
2018-09-26 15:24 ` Alexander Duyck
2018-09-26 15:39 ` Michal Hocko
2018-09-26 15:41 ` Dave Hansen
2018-09-26 16:18 ` Alexander Duyck
2018-09-26 15:36 ` Dave Hansen
2018-09-26 22:36 ` Andrew Morton
2018-09-25 20:20 ` Alexander Duyck [this message]
2018-09-25 20:21 ` [PATCH v5 4/4] mm: Defer ZONE_DEVICE page initialization to the point where we init pgmap Alexander Duyck
2018-09-26 7:55 ` Michal Hocko
2018-09-26 18:25 ` Alexander Duyck
2018-09-26 18:52 ` Dan Williams
2018-09-27 11:20 ` Michal Hocko
2018-09-27 11:09 ` Michal Hocko
2018-09-27 12:25 ` Oscar Salvador
2018-09-27 13:13 ` Michal Hocko
2018-09-27 14:50 ` Oscar Salvador
2018-09-27 15:41 ` David Hildenbrand
2018-09-28 8:12 ` Oscar Salvador
2018-09-28 8:44 ` Oscar Salvador
2018-09-28 15:50 ` Dan Williams
2018-09-27 12:32 ` Oscar Salvador
2018-10-08 21:01 ` Dan Williams
2018-10-08 21:38 ` Alexander Duyck
2018-10-08 22:00 ` Dan Williams
2018-10-08 22:07 ` Alexander Duyck
2018-10-08 22:36 ` Alexander Duyck
2018-10-08 22:59 ` Dan Williams
2018-10-08 23:34 ` [mm PATCH] memremap: Fix reference count for pgmap in devm_memremap_pages Alexander Duyck
2018-10-09 0:20 ` Dan Williams
2018-10-09 17:00 ` [PATCH v5 4/4] mm: Defer ZONE_DEVICE page initialization to the point where we init pgmap Yi Zhang
2018-10-09 18:04 ` Dan Williams
2018-10-09 20:26 ` Alexander Duyck
2018-10-09 21:19 ` Dan Williams
2018-10-10 12:52 ` Yi Zhang
2018-10-10 15:27 ` Alexander Duyck
2018-10-11 8:17 ` Yi Zhang
2018-10-10 9:58 ` Michal Hocko
2018-10-10 16:39 ` Alexander Duyck
2018-10-10 17:24 ` Michal Hocko
2018-10-10 17:39 ` Alexander Duyck
2018-10-10 17:53 ` Michal Hocko
2018-10-10 18:13 ` Alexander Duyck
2018-10-10 18:52 ` Michal Hocko
2018-10-11 8:55 ` Michal Hocko
2018-10-11 17:38 ` Alexander Duyck
2018-10-11 18:22 ` Dan Williams
2018-10-17 7:52 ` Michal Hocko
2018-10-17 15:02 ` Alexander Duyck
2018-10-29 14:12 ` Michal Hocko
2018-10-29 15:59 ` Alexander Duyck
2018-10-29 16:35 ` Michal Hocko
2018-10-29 17:01 ` Alexander Duyck
2018-10-29 17:24 ` Michal Hocko
2018-10-29 17:34 ` Dan Williams
2018-10-29 17:45 ` Michal Hocko
2018-10-29 17:42 ` Alexander Duyck
2018-10-29 18:18 ` Michal Hocko
2018-10-29 19:59 ` Alexander Duyck
2018-10-30 6:29 ` Michal Hocko
2018-10-30 6:55 ` Dan Williams
2018-10-30 8:17 ` Michal Hocko
2018-10-30 15:57 ` Dan Williams
2018-10-30 8:05 ` Oscar Salvador
2018-10-29 15:49 ` Dan Williams
2018-10-29 15:56 ` Michal Hocko
2018-10-10 18:18 ` Dan Williams
2018-10-11 8:39 ` Yi Zhang
2018-10-11 15:38 ` Alexander Duyck
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