From: Wei Yang <richardw.yang@linux.intel.com>
To: akpm@linux-foundation.org, dan.j.williams@intel.com,
aneesh.kumar@linux.ibm.com, kirill@shutemov.name,
yang.shi@linux.alibaba.com, richardw.yang@linux.intel.com,
thellstrom@vmware.com
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: [PATCH 4/5] mm/mremap: calculate extent in one place
Date: Sat, 18 Jan 2020 07:22:53 +0800 [thread overview]
Message-ID: <20200117232254.2792-5-richardw.yang@linux.intel.com> (raw)
In-Reply-To: <20200117232254.2792-1-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 | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/mm/mremap.c b/mm/mremap.c
index a258914f3ee1..37335a10779d 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -240,7 +240,7 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
unsigned long new_addr, unsigned long len,
bool need_rmap_locks)
{
- unsigned long extent, next, old_end;
+ unsigned long extent, old_next, new_next, old_end;
struct mmu_notifier_range range;
pmd_t *old_pmd, *new_pmd;
@@ -253,8 +253,9 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
for (; old_addr < old_end; old_addr += extent, new_addr += extent) {
cond_resched();
- next = pmd_addr_end(old_addr, old_end);
- extent = next - old_addr;
+ old_next = pmd_addr_end(old_addr, old_end);
+ new_next = pmd_addr_end(new_addr, new_addr + len);
+ extent = min((old_next - old_addr), (new_next - new_addr));
old_pmd = get_old_pmd(vma->vm_mm, old_addr);
if (!old_pmd)
continue;
@@ -298,9 +299,6 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
if (pte_alloc(new_vma->vm_mm, new_pmd))
break;
- next = pmd_addr_end(new_addr, new_addr + len);
- 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:[~2020-01-17 23:23 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-17 23:22 [PATCH 0/5] mm/mremap.c: cleanup move_page_tables() a little Wei Yang
2020-01-17 23:22 ` [PATCH 1/5] mm/mremap: format the check in move_normal_pmd() same as move_huge_pmd() Wei Yang
2020-01-17 23:22 ` [PATCH 2/5] mm/mremap: it is sure to have enough space when extent meets requirement Wei Yang
2020-01-17 23:22 ` [PATCH 3/5] mm/mremap: use pmd_addr_end to calculate next in move_page_tables() Wei Yang
2020-01-26 14:47 ` Dmitry Osipenko
2020-01-27 2:59 ` Andrew Morton
2020-01-29 17:18 ` Dmitry Osipenko
2020-01-29 23:59 ` Andrew Morton
2020-01-30 0:28 ` Stephen Rothwell
2020-01-28 0:43 ` Wei Yang
2020-01-28 15:59 ` Dmitry Osipenko
2020-01-28 23:29 ` Wei Yang
2020-01-28 23:35 ` Dmitry Osipenko
2020-01-29 0:28 ` Wei Yang
2020-01-29 18:56 ` Dmitry Osipenko
2020-01-29 9:47 ` Russell King - ARM Linux admin
2020-01-29 14:21 ` Dmitry Osipenko
2020-01-29 21:57 ` Wei Yang
2020-01-29 23:24 ` Russell King - ARM Linux admin
2020-01-30 1:30 ` Wei Yang
2020-01-30 14:15 ` Russell King - ARM Linux admin
2020-01-30 21:57 ` Wei Yang
2020-01-17 23:22 ` Wei Yang [this message]
2020-01-17 23:22 ` [PATCH 5/5] mm/mremap: start addresses are properly aligned Wei Yang
2020-01-19 0:07 ` [PATCH 0/5] mm/mremap.c: cleanup move_page_tables() a little Andrew Morton
2020-01-19 2:11 ` Wei Yang
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