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 12/63] mm: numa: Do not migrate or account for hinting faults on the zero page
Date: Fri, 27 Sep 2013 14:26:57 +0100 [thread overview]
Message-ID: <1380288468-5551-13-git-send-email-mgorman@suse.de> (raw)
In-Reply-To: <1380288468-5551-1-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 prevents trapping faults on the zero pages. For
tasks using the zero page this will reduce the number of PTE updates,
TLB flushes and hinting faults.
[peterz@infradead.org: Correct use of is_huge_zero_page]
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
mm/huge_memory.c | 10 +++++++++-
mm/memory.c | 1 +
2 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index ac5af18..dd94f4e 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1303,6 +1303,7 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
goto out_unlock;
page = pmd_page(pmd);
+ BUG_ON(is_huge_zero_page(page));
page_nid = page_to_nid(page);
count_vm_numa_event(NUMA_HINT_FAULTS);
if (page_nid == this_nid)
@@ -1493,8 +1494,15 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
} else {
struct page *page = pmd_page(*pmd);
- /* only check non-shared pages */
+ /*
+ * Only check non-shared pages. Do not trap faults
+ * against the zero page. The read-only data is likely
+ * to be read-cached on the local CPU cache and it is
+ * less useful to know about local vs remote hits on
+ * the zero page.
+ */
if (page_mapcount(page) == 1 &&
+ !is_huge_zero_page(page) &&
!pmd_numa(*pmd)) {
entry = pmdp_get_and_clear(mm, addr, pmd);
entry = pmd_mknuma(entry);
diff --git a/mm/memory.c b/mm/memory.c
index c20f872..86c3caf 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3575,6 +3575,7 @@ int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
pte_unmap_unlock(ptep, ptl);
return 0;
}
+ BUG_ON(is_zero_pfn(page_to_pfn(page)));
page_nid = page_to_nid(page);
target_nid = numa_migrate_prep(page, vma, addr, page_nid);
--
1.8.1.4
next prev parent reply other threads:[~2013-09-27 13:43 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-27 13:26 [PATCH 0/63] Basic scheduler support for automatic NUMA balancing V8 Mel Gorman
2013-09-27 13:26 ` [PATCH 01/63] sched: monolithic code dump of what is being pushed upstream Mel Gorman
2013-09-27 13:26 ` [PATCH 02/63] mm: numa: Document automatic NUMA balancing sysctls Mel Gorman
2013-09-27 13:26 ` [PATCH 03/63] sched, numa: Comment fixlets Mel Gorman
2013-09-27 13:26 ` [PATCH 04/63] mm: numa: Do not account for a hinting fault if we raced Mel Gorman
2013-09-27 13:26 ` [PATCH 05/63] mm: Wait for THP migrations to complete during NUMA hinting faults Mel Gorman
2013-09-27 13:26 ` [PATCH 06/63] mm: Prevent parallel splits during THP migration Mel Gorman
2013-09-27 13:26 ` [PATCH 07/63] mm: Account for a THP NUMA hinting update as one PTE update Mel Gorman
2013-09-27 13:26 ` [PATCH 08/63] mm: Do not flush TLB during protection change if !pte_present && !migration_entry Mel Gorman
2013-09-27 13:26 ` [PATCH 09/63] mm: Only flush TLBs if a transhuge PMD is modified for NUMA pte scanning Mel Gorman
2013-09-27 13:26 ` [PATCH 10/63] mm: numa: Sanitize task_numa_fault() callsites Mel Gorman
2013-09-27 13:26 ` [PATCH 11/63] mm: Close races between THP migration and PMD numa clearing Mel Gorman
2013-09-30 8:52 ` Mel Gorman
2013-09-30 14:10 ` Rik van Riel
2013-09-30 15:18 ` Mel Gorman
2013-09-27 13:26 ` Mel Gorman [this message]
2013-09-27 13:26 ` [PATCH 13/63] sched: numa: Mitigate chance that same task always updates PTEs Mel Gorman
2013-09-27 13:26 ` [PATCH 14/63] sched: numa: Continue PTE scanning even if migrate rate limited Mel Gorman
2013-09-27 13:27 ` [PATCH 15/63] Revert "mm: sched: numa: Delay PTE scanning until a task is scheduled on a new node" Mel Gorman
2013-09-27 13:27 ` [PATCH 16/63] sched: numa: Initialise numa_next_scan properly Mel Gorman
2013-09-27 13:27 ` [PATCH 17/63] sched: Set the scan rate proportional to the memory usage of the task being scanned Mel Gorman
2013-09-27 13:27 ` [PATCH 18/63] sched: numa: Slow scan rate if no NUMA hinting faults are being recorded Mel Gorman
2013-09-27 13:27 ` [PATCH 19/63] sched: Track NUMA hinting faults on per-node basis Mel Gorman
2013-09-27 13:27 ` [PATCH 20/63] sched: Select a preferred node with the most numa hinting faults Mel Gorman
2013-09-27 13:27 ` [PATCH 21/63] sched: Update NUMA hinting faults once per scan Mel Gorman
2013-09-27 13:27 ` [PATCH 22/63] sched: Favour moving tasks towards the preferred node Mel Gorman
2013-09-27 13:27 ` [PATCH 23/63] sched: Resist moving tasks towards nodes with fewer hinting faults Mel Gorman
2013-09-27 13:27 ` [PATCH 24/63] sched: Reschedule task on preferred NUMA node once selected Mel Gorman
2013-09-27 13:27 ` [PATCH 25/63] sched: Add infrastructure for split shared/private accounting of NUMA hinting faults Mel Gorman
2013-09-27 13:27 ` [PATCH 26/63] sched: Check current->mm before allocating NUMA faults Mel Gorman
2013-09-27 13:27 ` [PATCH 27/63] mm: numa: Scan pages with elevated page_mapcount Mel Gorman
2013-09-27 13:27 ` [PATCH 28/63] sched: Remove check that skips small VMAs Mel Gorman
2013-09-27 13:27 ` [PATCH 29/63] sched: Set preferred NUMA node based on number of private faults Mel Gorman
2013-09-27 13:27 ` [PATCH 30/63] sched: Do not migrate memory immediately after switching node Mel Gorman
2013-09-27 13:27 ` [PATCH 31/63] mm: numa: only unmap migrate-on-fault VMAs Mel Gorman
2013-09-27 13:27 ` [PATCH 32/63] sched: Avoid overloading CPUs on a preferred NUMA node Mel Gorman
2013-09-27 13:27 ` [PATCH 33/63] sched: Retry migration of tasks to CPU on a preferred node Mel Gorman
2013-09-27 13:27 ` [PATCH 34/63] sched: numa: increment numa_migrate_seq when task runs in correct location Mel Gorman
2013-09-27 13:27 ` [PATCH 35/63] sched: numa: Do not trap hinting faults for shared libraries Mel Gorman
2013-09-27 13:27 ` [PATCH 36/63] mm: numa: Only trap pmd hinting faults if we would otherwise trap PTE faults Mel Gorman
2013-09-27 13:27 ` [PATCH 37/63] stop_machine: Introduce stop_two_cpus() Mel Gorman
2013-09-27 13:27 ` [PATCH 38/63] sched: Introduce migrate_swap() Mel Gorman
2013-09-27 13:27 ` [PATCH 39/63] sched: numa: Use a system-wide search to find swap/migration candidates Mel Gorman
2013-09-27 13:27 ` [PATCH 40/63] sched: numa: Favor placing a task on the preferred node Mel Gorman
2013-09-27 13:27 ` [PATCH 41/63] sched: numa: fix placement of workloads spread across multiple nodes Mel Gorman
2013-09-27 13:27 ` [PATCH 42/63] mm: numa: Change page last {nid,pid} into {cpu,pid} Mel Gorman
2013-09-27 13:27 ` [PATCH 43/63] sched: numa: Use {cpu, pid} to create task groups for shared faults Mel Gorman
2013-09-27 13:27 ` [PATCH 44/63] sched: numa: Report a NUMA task group ID Mel Gorman
2013-09-27 13:27 ` [PATCH 45/63] mm: numa: copy cpupid on page migration Mel Gorman
2013-09-27 13:27 ` [PATCH 46/63] mm: numa: Do not group on RO pages Mel Gorman
2013-09-27 13:27 ` [PATCH 47/63] mm: numa: Do not batch handle PMD pages Mel Gorman
2013-09-27 13:27 ` [PATCH 48/63] sched: numa: stay on the same node if CLONE_VM Mel Gorman
2013-09-27 13:27 ` [PATCH 49/63] sched: numa: use group fault statistics in numa placement Mel Gorman
2013-09-27 13:27 ` [PATCH 50/63] sched: numa: call task_numa_free from do_execve Mel Gorman
2013-09-27 13:27 ` [PATCH 51/63] sched: numa: Prevent parallel updates to group stats during placement Mel Gorman
2013-09-27 13:27 ` [PATCH 52/63] sched: numa: add debugging Mel Gorman
2013-09-27 13:27 ` [PATCH 53/63] sched: numa: Decide whether to favour task or group weights based on swap candidate relationships Mel Gorman
2013-09-27 13:27 ` [PATCH 54/63] sched: numa: fix task or group comparison Mel Gorman
2013-09-27 13:27 ` [PATCH 55/63] sched: numa: Avoid migrating tasks that are placed on their preferred node Mel Gorman
2013-09-27 13:27 ` [PATCH 56/63] sched: numa: be more careful about joining numa groups Mel Gorman
2013-09-27 13:27 ` [PATCH 57/63] sched: numa: Take false sharing into account when adapting scan rate Mel Gorman
2013-09-27 13:27 ` [PATCH 58/63] sched: numa: adjust scan rate in task_numa_placement Mel Gorman
2013-09-27 13:27 ` [PATCH 59/63] sched: numa: Remove the numa_balancing_scan_period_reset sysctl Mel Gorman
2013-09-27 13:27 ` [PATCH 60/63] mm: numa: revert temporarily disabling of NUMA migration Mel Gorman
2013-09-27 13:27 ` [PATCH 61/63] sched: numa: skip some page migrations after a shared fault Mel Gorman
2013-09-27 13:27 ` [PATCH 62/63] sched: numa: use unsigned longs for numa group fault stats Mel Gorman
2013-09-27 13:27 ` [PATCH 63/63] sched: numa: periodically retry task_numa_migrate Mel Gorman
2013-10-24 4:32 ` [PATCH 0/63] Basic scheduler support for automatic NUMA balancing V8 Chegu Vinod
2013-10-07 10:28 [PATCH 0/63] Basic scheduler support for automatic NUMA balancing V9 Mel Gorman
2013-10-07 10:28 ` [PATCH 12/63] mm: numa: Do not migrate or account for hinting faults on the zero page Mel Gorman
2013-10-07 17:10 ` Rik van Riel
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=1380288468-5551-13-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;
as well as URLs for NNTP newsgroup(s).