From: Wei Yang <richard.weiyang@linux.alibaba.com>
To: akpm@linux-foundation.org, kirill.shutemov@linux.intel.com,
vbabka@suse.cz, yang.shi@linux.alibaba.com,
thomas_os@shipmail.org, anshuman.khandual@arm.com,
sean.j.christopherson@intel.com,
richard.weiyang@linux.alibaba.com, peterx@redhat.com,
aneesh.kumar@linux.ibm.com, willy@infradead.org,
thellstrom@vmware.com
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, digetx@gmail.com
Subject: [Patch v4 4/4] mm/mremap: use pmd_addr_end to simplify the calculate of extent
Date: Wed, 8 Jul 2020 17:50:28 +0800 [thread overview]
Message-ID: <20200708095028.41706-5-richard.weiyang@linux.alibaba.com> (raw)
In-Reply-To: <20200708095028.41706-1-richard.weiyang@linux.alibaba.com>
The purpose of this code is to calculate the smaller extent in old and
new range. Let's leverage pmd_addr_end() to do the calculation.
Hope this would make the code easier to read.
Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
---
v4: remove redundant parentheses pointed by Kirill
---
mm/mremap.c | 16 +++++++---------
1 file changed, 7 insertions(+), 9 deletions(-)
diff --git a/mm/mremap.c b/mm/mremap.c
index f5f17d050617..f6f56aa0b893 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -237,11 +237,12 @@ 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, new_end;
struct mmu_notifier_range range;
pmd_t *old_pmd, *new_pmd;
old_end = old_addr + len;
+ new_end = new_addr + len;
flush_cache_range(vma, old_addr, old_end);
mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, vma->vm_mm,
@@ -250,14 +251,11 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
for (; old_addr < old_end; old_addr += extent, new_addr += extent) {
cond_resched();
- next = (old_addr + PMD_SIZE) & PMD_MASK;
- /* even if next overflowed, extent below will be ok */
- 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_next = pmd_addr_end(old_addr, old_end);
+ new_next = pmd_addr_end(new_addr, new_end);
+ extent = min(old_next - old_addr, new_next - new_addr);
+
old_pmd = get_old_pmd(vma->vm_mm, old_addr);
if (!old_pmd)
continue;
--
2.20.1 (Apple Git-117)
next prev parent reply other threads:[~2020-07-08 9:50 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-08 9:50 [Patch v4 0/4] mm/mremap: cleanup move_page_tables() a little Wei Yang
2020-07-08 9:50 ` [Patch v4 1/4] mm/mremap: it is sure to have enough space when extent meets requirement Wei Yang
2020-07-08 9:50 ` [Patch v4 2/4] mm/mremap: calculate extent in one place Wei Yang
2020-07-08 9:50 ` [Patch v4 3/4] mm/mremap: start addresses are properly aligned Wei Yang
2020-07-08 9:50 ` Wei Yang [this message]
2020-07-09 19:38 ` [Patch v4 0/4] mm/mremap: cleanup move_page_tables() a little Dmitry Osipenko
2020-07-10 1:14 ` Wei Yang
2020-07-10 8:14 ` Kirill A. Shutemov
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