From: Alexander Duyck <alexander.duyck@gmail.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux-nvdimm@lists.01.org
Cc: pavel.tatashin@microsoft.com, mhocko@suse.com,
dave.hansen@intel.com, jglisse@redhat.com,
akpm@linux-foundation.org, mingo@kernel.org,
kirill.shutemov@linux.intel.com
Subject: [PATCH 2/4] mm: Create non-atomic version of SetPageReserved for init use
Date: Mon, 10 Sep 2018 16:43:48 -0700 [thread overview]
Message-ID: <20180910234348.4068.92164.stgit@localhost.localdomain> (raw)
In-Reply-To: <20180910232615.4068.29155.stgit@localhost.localdomain>
From: Alexander Duyck <alexander.h.duyck@intel.com>
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 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>
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
---
include/linux/page-flags.h | 1 +
mm/page_alloc.c | 17 +++++++++++++++--
2 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index d00216cf00f8..1b1f8e0378ae 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -300,6 +300,7 @@ 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 89d2a2ab3fe6..a9b095a72fd9 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1231,7 +1231,12 @@ 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);
}
}
}
@@ -5517,8 +5522,16 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
not_early:
page = pfn_to_page(pfn);
__init_single_page(page, pfn, zone, nid);
+
+ /*
+ * Mark page reserved as it will need to wait for onlining
+ * phase for it to be fully associated with a zone.
+ *
+ * We can use the non-atomic __set_bit operation for setting
+ * the flag as we are still initializing the pages.
+ */
if (context == MEMMAP_HOTPLUG)
- SetPageReserved(page);
+ __SetPageReserved(page);
/*
* Mark the block movable so that blocks are reserved for
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next prev parent reply other threads:[~2018-09-10 23:43 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-10 23:43 [PATCH 0/4] Address issues slowing persistent memory initialization Alexander Duyck
2018-09-10 23:43 ` [PATCH 1/4] mm: Provide kernel parameter to allow disabling page init poisoning Alexander Duyck
2018-09-11 0:35 ` Alexander Duyck
2018-09-11 16:50 ` Dan Williams
2018-09-11 20:01 ` Alexander Duyck
2018-09-11 20:24 ` Dan Williams
2018-09-12 13:24 ` Pasha Tatashin
2018-09-12 14:10 ` Michal Hocko
2018-09-12 14:49 ` Alexander Duyck
2018-09-12 15:23 ` Dave Hansen
2018-09-12 16:36 ` Alexander Duyck
2018-09-12 16:43 ` Dave Hansen
2018-09-10 23:43 ` Alexander Duyck [this message]
2018-09-12 13:28 ` [PATCH 2/4] mm: Create non-atomic version of SetPageReserved for init use Pasha Tatashin
2018-09-10 23:43 ` [PATCH 3/4] mm: Defer ZONE_DEVICE page initialization to the point where we init pgmap Alexander Duyck
2018-09-11 7:49 ` kbuild test robot
2018-09-11 7:54 ` kbuild test robot
2018-09-11 22:35 ` Dan Williams
2018-09-12 0:51 ` Alexander Duyck
2018-09-12 0:59 ` Dan Williams
2018-09-12 13:59 ` Pasha Tatashin
2018-09-12 15:48 ` Alexander Duyck
2018-09-12 15:54 ` Pasha Tatashin
2018-09-12 16:44 ` Alexander Duyck
2018-09-12 16:50 ` Dan Williams
2018-09-12 17:46 ` Pasha Tatashin
2018-09-12 19:11 ` Dan Williams
2018-09-10 23:44 ` [PATCH 4/4] nvdimm: Trigger the device probe on a cpu local to the device Alexander Duyck
2018-09-11 0:37 ` Alexander Duyck
2018-09-12 5:48 ` Dan Williams
2018-09-12 13:44 ` Pasha Tatashin
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