From: Mel Gorman <mgorman@suse.de>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Rik van Riel <riel@redhat.com>, Hugh Dickins <hughd@google.com>,
Linux Kernel <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>, Ingo Molnar <mingo@redhat.com>,
Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>,
Sasha Levin <sasha.levin@oracle.com>,
LinuxPPC-dev <linuxppc-dev@lists.ozlabs.org>,
Kirill Shutemov <kirill.shutemov@linux.intel.com>,
Mel Gorman <mgorman@suse.de>
Subject: [PATCH 10/10] mm: numa: Avoid unnecessary TLB flushes when setting NUMA hinting entries
Date: Mon, 5 Jan 2015 10:54:11 +0000 [thread overview]
Message-ID: <1420455251-13644-11-git-send-email-mgorman@suse.de> (raw)
In-Reply-To: <1420455251-13644-1-git-send-email-mgorman@suse.de>
If a PTE or PMD is already marked NUMA when scanning to mark entries
for NUMA hinting then it is not necessary to update the entry and
incur a TLB flush penalty. Avoid the avoidhead where possible.
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
mm/huge_memory.c | 14 ++++++++------
mm/mprotect.c | 4 ++++
2 files changed, 12 insertions(+), 6 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 8546654..f2bf521 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1524,12 +1524,14 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
return 0;
}
- ret = 1;
- entry = pmdp_get_and_clear_notify(mm, addr, pmd);
- entry = pmd_modify(entry, newprot);
- ret = HPAGE_PMD_NR;
- set_pmd_at(mm, addr, pmd, entry);
- BUG_ON(pmd_write(entry));
+ if (!prot_numa || !pmd_protnone(*pmd)) {
+ ret = 1;
+ entry = pmdp_get_and_clear_notify(mm, addr, pmd);
+ entry = pmd_modify(entry, newprot);
+ ret = HPAGE_PMD_NR;
+ set_pmd_at(mm, addr, pmd, entry);
+ BUG_ON(pmd_write(entry));
+ }
spin_unlock(ptl);
}
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 33dfafb..109e7aa 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -86,6 +86,10 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
page = vm_normal_page(vma, addr, oldpte);
if (!page || PageKsm(page))
continue;
+
+ /* Avoid TLB flush if possible */
+ if (pte_protnone(oldpte))
+ continue;
}
ptent = ptep_modify_prot_start(mm, addr, pte);
--
2.1.2
next prev parent reply other threads:[~2015-01-05 10:54 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-05 10:54 [PATCH 0/10] Replace _PAGE_NUMA with PAGE_NONE protections v5 Mel Gorman
2015-01-05 10:54 ` [PATCH 01/10] mm: numa: Do not dereference pmd outside of the lock during NUMA hinting fault Mel Gorman
2015-01-05 10:54 ` [PATCH 02/10] mm: Add p[te|md] protnone helpers for use by NUMA balancing Mel Gorman
2015-01-05 10:54 ` [PATCH 03/10] mm: Convert p[te|md]_numa users to p[te|md]_protnone_numa Mel Gorman
2015-01-05 10:54 ` [PATCH 04/10] ppc64: Add paranoid warnings for unexpected DSISR_PROTFAULT Mel Gorman
2015-01-05 10:54 ` [PATCH 05/10] mm: Convert p[te|md]_mknonnuma and remaining page table manipulations Mel Gorman
2015-01-05 10:54 ` [PATCH 06/10] mm: Remove remaining references to NUMA hinting bits and helpers Mel Gorman
2015-01-05 10:54 ` [PATCH 07/10] mm: numa: Do not trap faults on the huge zero page Mel Gorman
2015-01-05 10:54 ` [PATCH 08/10] x86: mm: Restore original pte_special check Mel Gorman
2015-01-05 10:54 ` [PATCH 09/10] mm: numa: Add paranoid check around pte_protnone_numa Mel Gorman
2015-01-05 10:54 ` Mel Gorman [this message]
-- strict thread matches above, loose matches on Subject: below --
2014-12-04 11:24 [PATCH 0/10] Replace _PAGE_NUMA with PAGE_NONE protections v4 Mel Gorman
2014-12-04 11:24 ` [PATCH 10/10] mm: numa: Avoid unnecessary TLB flushes when setting NUMA hinting entries Mel Gorman
2014-11-21 13:57 [PATCH 0/10] Replace _PAGE_NUMA with PAGE_NONE protections v3 Mel Gorman
2014-11-21 13:57 ` [PATCH 10/10] mm: numa: Avoid unnecessary TLB flushes when setting NUMA hinting entries Mel Gorman
2014-11-20 10:19 [PATCH 0/10] Replace _PAGE_NUMA with PAGE_NONE protections v2 Mel Gorman
2014-11-20 10:19 ` [PATCH 10/10] mm: numa: Avoid unnecessary TLB flushes when setting NUMA hinting entries Mel Gorman
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