From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Date: Tue, 10 May 2022 23:28:47 +0000 Subject: Re: [PATCH v3 2/3] mm: rmap: Fix CONT-PTE/PMD size hugetlb issue when migration Message-Id: <20220510162847.d9cf3c767e755a54699fb121@linux-foundation.org> List-Id: References: <20220510161739.fdea4d78dde8471033aab22b@linux-foundation.org> In-Reply-To: <20220510161739.fdea4d78dde8471033aab22b@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Baolin Wang , mike.kravetz@oracle.com, catalin.marinas@arm.com, will@kernel.org, songmuchun@bytedance.com, 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.osdn.me, 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 On Tue, 10 May 2022 16:17:39 -0700 Andrew Morton wrote: > > + > > +static inline pte_t huge_ptep_clear_flush(struct vm_area_struct *vma, > > + unsigned long addr, pte_t *ptep) > > +{ > > + return ptep_get(ptep); > > +} > > + > > +static inline void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, > > + pte_t *ptep, pte_t pte) > > +{ > > +} > > #endif /* CONFIG_HUGETLB_PAGE */ > > > > This blows up nommu (arm allnoconfig): > > In file included from fs/io_uring.c:71: > ./include/linux/hugetlb.h: In function 'huge_ptep_clear_flush': > ./include/linux/hugetlb.h:1100:16: error: implicit declaration of function 'ptep_get' [-Werror=implicit-function-declaration] > 1100 | return ptep_get(ptep); > | ^~~~~~~~ > > > huge_ptep_clear_flush() is only used in CONFIG_NOMMU=n files, so I simply > zapped this change. > Well that wasn't a great success. Doing this instead. It's pretty nasty - something nicer would be nicer please. --- a/include/linux/hugetlb.h~mm-rmap-fix-cont-pte-pmd-size-hugetlb-issue-when-migration-fix +++ a/include/linux/hugetlb.h @@ -1094,6 +1094,7 @@ static inline void set_huge_swap_pte_at( { } +#ifdef CONFIG_MMU static inline pte_t huge_ptep_clear_flush(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep) { @@ -1104,6 +1105,7 @@ static inline void set_huge_pte_at(struc pte_t *ptep, pte_t pte) { } +#endif #endif /* CONFIG_HUGETLB_PAGE */ static inline spinlock_t *huge_pte_lock(struct hstate *h, _