From: Mel Gorman <mgorman@suse.de>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>, Rik van Riel <riel@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
Ingo Molnar <mingo@kernel.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>, Mel Gorman <mgorman@suse.de>
Subject: [PATCH 04/27] mm: numa: Do not migrate or account for hinting faults on the zero page
Date: Thu, 8 Aug 2013 15:00:16 +0100 [thread overview]
Message-ID: <1375970439-5111-5-git-send-email-mgorman@suse.de> (raw)
In-Reply-To: <1375970439-5111-1-git-send-email-mgorman@suse.de>
The zero page is not replicated between nodes and is often shared
between processes. The data is read-only and likely to be cached in
local CPUs if heavily accessed meaning that the remote memory access
cost is less of a concern. This patch stops accounting for numa hinting
faults on the zero page in both terms of counting faults and scheduling
tasks on nodes.
[peterz@infradead.org: Correct use of is_huge_zero_page]
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
mm/huge_memory.c | 9 +++++++++
mm/memory.c | 7 ++++++-
2 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index e52c131..4ebe3aa 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1301,6 +1301,15 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
goto out_unlock;
page = pmd_page(pmd);
+
+ /*
+ * Do not account for faults against the huge zero page. The read-only
+ * data is likely to be read-cached on the local CPUs and it is less
+ * useful to know about local versus remote hits on the zero page.
+ */
+ if (is_huge_zero_page(page))
+ goto clear_pmdnuma;
+
get_page(page);
src_nid = numa_node_id();
count_vm_numa_event(NUMA_HINT_FAULTS);
diff --git a/mm/memory.c b/mm/memory.c
index 1ce2e2a..871b881 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3557,8 +3557,13 @@ int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
set_pte_at(mm, addr, ptep, pte);
update_mmu_cache(vma, addr, ptep);
+ /*
+ * Do not account for faults against the zero page. The read-only data
+ * is likely to be read-cached on the local CPUs and it is less useful
+ * to know about local versus remote hits on the zero page.
+ */
page = vm_normal_page(vma, addr, pte);
- if (!page) {
+ if (!page || is_zero_pfn(page_to_pfn(page))) {
pte_unmap_unlock(ptep, ptl);
return 0;
}
--
1.8.1.4
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2013-08-08 14:00 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-08 14:00 [PATCH 0/27] Basic scheduler support for automatic NUMA balancing V6 Mel Gorman
2013-08-08 14:00 ` [PATCH 01/27] mm: numa: Document automatic NUMA balancing sysctls Mel Gorman
2013-08-08 14:00 ` [PATCH 02/27] sched, numa: Comment fixlets Mel Gorman
2013-08-08 14:00 ` [PATCH 03/27] mm: numa: Account for THP numa hinting faults on the correct node Mel Gorman
2013-08-08 14:00 ` Mel Gorman [this message]
2013-08-08 14:00 ` [PATCH 05/27] mm, numa: Sanitize task_numa_fault() callsites Mel Gorman
2013-08-08 14:00 ` [PATCH 06/27] sched, numa: Mitigate chance that same task always updates PTEs Mel Gorman
2013-08-08 14:00 ` [PATCH 07/27] sched, numa: Continue PTE scanning even if migrate rate limited Mel Gorman
2013-08-08 14:00 ` [PATCH 08/27] Revert "mm: sched: numa: Delay PTE scanning until a task is scheduled on a new node" Mel Gorman
2013-08-08 14:00 ` [PATCH 09/27] sched: numa: Initialise numa_next_scan properly Mel Gorman
2013-08-08 14:00 ` [PATCH 10/27] sched: numa: Slow scan rate if no NUMA hinting faults are being recorded Mel Gorman
2013-08-08 14:00 ` [PATCH 11/27] sched: Set the scan rate proportional to the memory usage of the task being scanned Mel Gorman
2013-08-08 14:00 ` [PATCH 12/27] sched: numa: Correct adjustment of numa_scan_period Mel Gorman
2013-08-08 14:00 ` [PATCH 13/27] mm: Only flush TLBs if a transhuge PMD is modified for NUMA pte scanning Mel Gorman
2013-08-08 14:00 ` [PATCH 14/27] mm: Do not flush TLB during protection change if !pte_present && !migration_entry Mel Gorman
2013-08-08 14:00 ` [PATCH 15/27] sched: Track NUMA hinting faults on per-node basis Mel Gorman
2013-08-08 14:00 ` [PATCH 16/27] sched: Select a preferred node with the most numa hinting faults Mel Gorman
2013-08-08 14:00 ` [PATCH 17/27] sched: Update NUMA hinting faults once per scan Mel Gorman
2013-08-08 14:00 ` [PATCH 18/27] sched: Favour moving tasks towards the preferred node Mel Gorman
2013-08-08 14:00 ` [PATCH 19/27] sched: Resist moving tasks towards nodes with fewer hinting faults Mel Gorman
2013-08-08 14:00 ` [PATCH 20/27] sched: Reschedule task on preferred NUMA node once selected Mel Gorman
2013-08-08 14:00 ` [PATCH 21/27] sched: Add infrastructure for split shared/private accounting of NUMA hinting faults Mel Gorman
2013-08-08 14:00 ` [PATCH 22/27] sched: Check current->mm before allocating NUMA faults Mel Gorman
2013-08-08 14:00 ` [PATCH 23/27] mm: numa: Scan pages with elevated page_mapcount Mel Gorman
2013-08-08 14:00 ` [PATCH 24/27] sched: Remove check that skips small VMAs Mel Gorman
2013-08-08 14:00 ` [PATCH 25/27] sched: Set preferred NUMA node based on number of private faults Mel Gorman
2013-08-08 14:00 ` [PATCH 26/27] sched: Avoid overloading CPUs on a preferred NUMA node Mel Gorman
2013-08-08 14:00 ` [PATCH 27/27] sched: Retry migration of tasks to CPU on a preferred node Mel Gorman
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=1375970439-5111-5-git-send-email-mgorman@suse.de \
--to=mgorman@suse.de \
--cc=a.p.zijlstra@chello.nl \
--cc=aarcange@redhat.com \
--cc=hannes@cmpxchg.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mingo@kernel.org \
--cc=riel@redhat.com \
--cc=srikar@linux.vnet.ibm.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