From: Muchun Song <songmuchun@bytedance.com>
To: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: akpm@linux-foundation.org, mike.kravetz@oracle.com,
catalin.marinas@arm.com, will@kernel.org,
tsbogend@alpha.franken.de, James.Bottomley@HansenPartnership.com,
deller@gmx.de, mpe@ellerman.id.au, benh@kernel.crashing.org,
paulus@samba.org, hca@linux.ibm.com, gor@linux.ibm.com,
agordeev@linux.ibm.com, borntraeger@linux.ibm.com,
svens@linux.ibm.com, ysato@users.sourceforge.jp, dalias@libc.org,
davem@davemloft.net, arnd@arndb.de,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org,
linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org,
linux-sh@vger.kernel.org, sparclinux@vger.kernel.org,
linux-arch@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH v2 1/3] mm: change huge_ptep_clear_flush() to return the original pte
Date: Mon, 9 May 2022 12:06:43 +0800 [thread overview]
Message-ID: <YniTU+iT/pV5j/41@FVFYT0MHHV2J.usts.net> (raw)
In-Reply-To: <bf627d1a-42f8-77f3-6ac2-67edde2feb8a@linux.alibaba.com>
On Sun, May 08, 2022 at 09:09:55PM +0800, Baolin Wang wrote:
>
>
> On 5/8/2022 7:09 PM, Muchun Song wrote:
> > On Sun, May 08, 2022 at 05:36:39PM +0800, Baolin Wang wrote:
> > > It is incorrect to use ptep_clear_flush() to nuke a hugetlb page
> > > table when unmapping or migrating a hugetlb page, and will change
> > > to use huge_ptep_clear_flush() instead in the following patches.
> > >
> > > So this is a preparation patch, which changes the huge_ptep_clear_flush()
> > > to return the original pte to help to nuke a hugetlb page table.
> > >
> > > Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
> > > Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
> >
> > Reviewed-by: Muchun Song <songmuchun@bytedance.com>
>
> Thanks for reviewing.
>
> >
> > But one nit below:
> >
> > [...]
> > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> > > index 8605d7e..61a21af 100644
> > > --- a/mm/hugetlb.c
> > > +++ b/mm/hugetlb.c
> > > @@ -5342,7 +5342,7 @@ static vm_fault_t hugetlb_wp(struct mm_struct *mm, struct vm_area_struct *vma,
> > > ClearHPageRestoreReserve(new_page);
> > > /* Break COW or unshare */
> > > - huge_ptep_clear_flush(vma, haddr, ptep);
> > > + (void)huge_ptep_clear_flush(vma, haddr, ptep);
> >
> > Why add a "(void)" here? Is there any warning if no "(void)"?
> > IIUC, I think we can remove this, right?
>
> I did not meet any warning without the casting, but this is per Mike's
> comment[1] to make the code consistent with other functions casting to void
> type explicitly in hugetlb.c file.
>
Got it. I see hugetlb.c per this rule, while others do not.
> [1]
> https://lore.kernel.org/all/495c4ebe-a5b4-afb6-4cb0-956c1b18d0cc@oracle.com/
>
next prev parent reply other threads:[~2022-05-09 4:14 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-08 9:36 [PATCH v2 0/3] Fix CONT-PTE/PMD size hugetlb issue when unmapping or migrating Baolin Wang
2022-05-08 9:36 ` [PATCH v2 1/3] mm: change huge_ptep_clear_flush() to return the original pte Baolin Wang
2022-05-08 11:09 ` Muchun Song
2022-05-08 13:09 ` Baolin Wang
2022-05-09 4:06 ` Muchun Song [this message]
2022-05-09 5:46 ` Christophe Leroy
2022-05-09 8:46 ` Baolin Wang
2022-05-09 20:02 ` Mike Kravetz
2022-05-10 1:35 ` Baolin Wang
2022-05-08 9:36 ` [PATCH v2 2/3] mm: rmap: Fix CONT-PTE/PMD size hugetlb issue when migration Baolin Wang
2022-05-08 12:01 ` kernel test robot
2022-05-08 13:13 ` Baolin Wang
2022-05-08 12:11 ` kernel test robot
2022-05-08 13:31 ` Muchun Song
2022-05-09 21:05 ` Mike Kravetz
2022-05-08 9:36 ` [PATCH v2 3/3] mm: rmap: Fix CONT-PTE/PMD size hugetlb issue when unmapping Baolin Wang
2022-05-09 6:42 ` Muchun Song
2022-05-09 22:25 ` Mike Kravetz
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