From: Wei Yang <richardw.yang@linux.intel.com>
To: akpm@linux-foundation.org, aneesh.kumar@linux.ibm.com,
kirill@shutemov.name, dan.j.williams@intel.com,
yang.shi@linux.alibaba.com, thellstrom@vmware.com,
richardw.yang@linux.intel.com
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, digetx@gmail.com
Subject: [Patch v2 3/4] mm/mremap: calculate extent in one place
Date: Wed, 29 Jan 2020 08:26:41 +0800 [thread overview]
Message-ID: <20200129002642.13508-4-richardw.yang@linux.intel.com> (raw)
In-Reply-To: <20200129002642.13508-1-richardw.yang@linux.intel.com>
Page tables is moved on the base of PMD. This requires both source
and destination range should meet the requirement.
Current code works well since move_huge_pmd() and move_normal_pmd()
would check old_addr and new_addr again. And then return to move_ptes()
if the either of them is not aligned.
In stead of calculating the extent separately, it is better to calculate
in one place, so we know it is not necessary to try move pmd. By doing
so, the logic seems a little clear.
Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
---
mm/mremap.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/mm/mremap.c b/mm/mremap.c
index c2af8ba4ba43..b2f3344d090a 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -258,6 +258,9 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
extent = next - old_addr;
if (extent > old_end - old_addr)
extent = old_end - old_addr;
+ next = (new_addr + PMD_SIZE) & PMD_MASK;
+ if (extent > next - new_addr)
+ extent = next - new_addr;
old_pmd = get_old_pmd(vma->vm_mm, old_addr);
if (!old_pmd)
continue;
@@ -301,9 +304,6 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
if (pte_alloc(new_vma->vm_mm, new_pmd))
break;
- next = (new_addr + PMD_SIZE) & PMD_MASK;
- if (extent > next - new_addr)
- extent = next - new_addr;
move_ptes(vma, old_pmd, old_addr, old_addr + extent, new_vma,
new_pmd, new_addr, need_rmap_locks);
}
--
2.17.1
next prev parent reply other threads:[~2020-01-29 0:27 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-29 0:26 [Patch v2 0/4] mm/mremap: cleanup move_page_tables() a little Wei Yang
2020-01-29 0:26 ` [Patch v2 1/4] mm/mremap: format the check in move_normal_pmd() same as move_huge_pmd() Wei Yang
2020-01-29 0:26 ` [Patch v2 2/4] mm/mremap: it is sure to have enough space when extent meets requirement Wei Yang
2020-01-29 0:26 ` Wei Yang [this message]
2020-01-29 0:26 ` [Patch v2 4/4] mm/mremap: start addresses are properly aligned Wei Yang
2020-01-30 22:18 ` [Patch v2 0/4] mm/mremap: cleanup move_page_tables() a little Dmitry Osipenko
2020-01-30 23:05 ` Wei Yang
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