Revision d483da5bc78b86fe4200d2947f193a745f711713 authored by Alexander Duyck on 26 October 2018, 22:07:48 UTC, committed by Linus Torvalds on 26 October 2018, 23:26:34 UTC
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 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. Link: http://lkml.kernel.org/r/20180925202018.3576.11607.stgit@localhost.localdomain Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com> Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent f682a97
COPYING
The Linux Kernel is provided under:
SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note
Being under the terms of the GNU General Public License version 2 only,
according with:
LICENSES/preferred/GPL-2.0
With an explicit syscall exception, as stated at:
LICENSES/exceptions/Linux-syscall-note
In addition, other licenses may also apply. Please see:
Documentation/process/license-rules.rst
for more details.
![swh spinner](/static/img/swh-spinner.gif)
Computing file changes ...