From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: linux-mm@kvack.org, akpm@linux-foundation.org,
kirill.shutemov@linux.intel.com, n-horiguchi@ah.jp.nec.com,
aarcange@redhat.com, riel@redhat.com, iamjoonsoo.kim@lge.com,
xiexiuqi@huawei.com, gorcunov@openvz.org,
linux-kernel@vger.kernel.org, mgorman@suse.de,
rientjes@google.com, vbabka@suse.cz,
aneesh.kumar@linux.vnet.ibm.com, hughd@google.com,
hannes@cmpxchg.org, mhocko@suse.cz, boaz@plexistor.com,
raindel@mellanox.com
Subject: Re: [RFC v5 3/3] mm: make swapin readahead to improve thp collapse rate
Date: Thu, 17 Sep 2015 16:28:25 +0300 [thread overview]
Message-ID: <20150917132825.GA30954@node.dhcp.inet.fi> (raw)
In-Reply-To: <1442259105-4420-4-git-send-email-ebru.akagunduz@gmail.com>
On Mon, Sep 14, 2015 at 10:31:45PM +0300, Ebru Akagunduz wrote:
> @@ -2655,6 +2696,8 @@ static void collapse_huge_page(struct mm_struct *mm,
>
> anon_vma_lock_write(vma->anon_vma);
>
> + __collapse_huge_page_swapin(mm, vma, address, pmd, pte);
> +
Do I miss something, or 'pte' is not initialized at this point?
And the value is not really used in __collapse_huge_page_swapin().
> pte = pte_offset_map(pmd, address);
> pte_ptl = pte_lockptr(mm, pmd);
WARNING: multiple messages have this Message-ID (diff)
From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: linux-mm@kvack.org, akpm@linux-foundation.org,
kirill.shutemov@linux.intel.com, n-horiguchi@ah.jp.nec.com,
aarcange@redhat.com, riel@redhat.com, iamjoonsoo.kim@lge.com,
xiexiuqi@huawei.com, gorcunov@openvz.org,
linux-kernel@vger.kernel.org, mgorman@suse.de,
rientjes@google.com, vbabka@suse.cz,
aneesh.kumar@linux.vnet.ibm.com, hughd@google.com,
hannes@cmpxchg.org, mhocko@suse.cz, boaz@plexistor.com,
raindel@mellanox.com
Subject: Re: [RFC v5 3/3] mm: make swapin readahead to improve thp collapse rate
Date: Thu, 17 Sep 2015 16:28:25 +0300 [thread overview]
Message-ID: <20150917132825.GA30954@node.dhcp.inet.fi> (raw)
In-Reply-To: <1442259105-4420-4-git-send-email-ebru.akagunduz@gmail.com>
On Mon, Sep 14, 2015 at 10:31:45PM +0300, Ebru Akagunduz wrote:
> @@ -2655,6 +2696,8 @@ static void collapse_huge_page(struct mm_struct *mm,
>
> anon_vma_lock_write(vma->anon_vma);
>
> + __collapse_huge_page_swapin(mm, vma, address, pmd, pte);
> +
Do I miss something, or 'pte' is not initialized at this point?
And the value is not really used in __collapse_huge_page_swapin().
> pte = pte_offset_map(pmd, address);
> pte_ptl = pte_lockptr(mm, pmd);
>From 76783e1dfb22cde04cf46903336810df8a632617 Mon Sep 17 00:00:00 2001
From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Date: Thu, 17 Sep 2015 16:23:30 +0300
Subject: [PATCH] khugepaged: __collapse_huge_page_swapin(): drop unused 'pte'
parameter
'pte' dereference is eliminated by compiler, since nobody uses the
pteval until it's overwritten inside the loop.
Value of 'pte' itself is overwritten by pte_offset_map() before first
real use.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
mm/huge_memory.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 4b057abd8615..5ad5c443cc94 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2628,11 +2628,10 @@ static bool hugepage_vma_check(struct vm_area_struct *vma)
static void __collapse_huge_page_swapin(struct mm_struct *mm,
struct vm_area_struct *vma,
- unsigned long address, pmd_t *pmd,
- pte_t *pte)
+ unsigned long address, pmd_t *pmd)
{
unsigned long _address;
- pte_t pteval = *pte;
+ pte_t *pte, pteval;
int swapped_in = 0, ret = 0;
pte = pte_offset_map(pmd, address);
@@ -2730,7 +2729,7 @@ static void collapse_huge_page(struct mm_struct *mm,
anon_vma_lock_write(vma->anon_vma);
- __collapse_huge_page_swapin(mm, vma, address, pmd, pte);
+ __collapse_huge_page_swapin(mm, vma, address, pmd);
pte = pte_offset_map(pmd, address);
pte_ptl = pte_lockptr(mm, pmd);
--
Kirill A. Shutemov
next prev parent reply other threads:[~2015-09-17 13:28 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-14 19:31 [RFC v5 0/3] mm: make swapin readahead to gain more thp performance Ebru Akagunduz
2015-09-14 19:31 ` Ebru Akagunduz
2015-09-14 19:31 ` [RFC v5 1/3] mm: add tracepoint for scanning pages Ebru Akagunduz
2015-09-14 19:31 ` Ebru Akagunduz
2015-09-14 19:31 ` [RFC v5 2/3] mm: make optimistic check for swapin readahead Ebru Akagunduz
2015-09-14 19:31 ` Ebru Akagunduz
2015-09-14 19:47 ` Rik van Riel
2015-09-14 19:47 ` Rik van Riel
2015-09-14 21:33 ` Andrew Morton
2015-09-14 21:33 ` Andrew Morton
2015-09-15 20:08 ` Ebru Akagunduz
2015-09-15 20:08 ` Ebru Akagunduz
2015-09-14 19:31 ` [RFC v5 3/3] mm: make swapin readahead to improve thp collapse rate Ebru Akagunduz
2015-09-14 19:31 ` Ebru Akagunduz
2015-09-17 13:28 ` Kirill A. Shutemov [this message]
2015-09-17 13:28 ` Kirill A. Shutemov
2015-09-17 15:13 ` Kirill A. Shutemov
2015-09-17 15:13 ` Kirill A. Shutemov
2015-09-14 21:41 ` [RFC v5 0/3] mm: make swapin readahead to gain more thp performance Andrew Morton
2015-09-14 21:41 ` Andrew Morton
2016-02-25 7:36 ` Hugh Dickins
2016-02-25 7:36 ` Hugh Dickins
2016-02-25 22:35 ` Rik van Riel
2016-02-25 23:30 ` Ebru Akagunduz
2016-02-25 23:30 ` Ebru Akagunduz
2016-02-26 6:17 ` Hugh Dickins
2016-02-26 14:51 ` Rik van Riel
2016-03-03 22:08 ` Ebru Akagunduz
2016-03-03 22:08 ` Ebru Akagunduz
2016-02-25 23:16 ` Ebru Akagunduz
2016-02-25 23:16 ` Ebru Akagunduz
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