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[2003:cb:c70b:1600:c48b:1fab:a330:5182]) by smtp.gmail.com with ESMTPSA id v8-20020a05600c214800b003a5c244fc13sm21831085wml.2.2022.08.23.03.07.04 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 23 Aug 2022 03:07:05 -0700 (PDT) Message-ID: <36925544-8127-fe0c-76e5-49138dff45ae@redhat.com> Date: Tue, 23 Aug 2022 12:07:04 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [PATCH v6 2/2] mm: fix the handling Non-LRU pages returned by follow_page Content-Language: en-US To: Miaohe Lin , Haiyue Wang , linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: akpm@linux-foundation.org, apopple@nvidia.com, ying.huang@intel.com, songmuchun@bytedance.com, naoya.horiguchi@linux.dev, alex.sierra@amd.com, Felix Kuehling References: <20220812084921.409142-1-haiyue.wang@intel.com> <20220816022102.582865-1-haiyue.wang@intel.com> <20220816022102.582865-3-haiyue.wang@intel.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 17.08.22 04:34, Miaohe Lin wrote: > On 2022/8/16 10:21, Haiyue Wang wrote: >> The handling Non-LRU pages returned by follow_page() jumps directly, it >> doesn't call put_page() to handle the reference count, since 'FOLL_GET' >> flag for follow_page() has get_page() called. Fix the zone device page >> check by handling the page reference count correctly before returning. >> >> And as David reviewed, "device pages are never PageKsm pages". Drop this >> zone device page check for break_ksm(). >> >> Fixes: 3218f8712d6b ("mm: handling Non-LRU pages returned by vm_normal_pages") >> Signed-off-by: Haiyue Wang >> Reviewed-by: "Huang, Ying" >> Reviewed-by: Felix Kuehling > > Thanks for your fixing. LGTM with one nit below. But I have no strong opinion on it. > So with or without fixing below nit: > > Reviewed-by: Miaohe Lin > >> --- >> mm/huge_memory.c | 4 ++-- >> mm/ksm.c | 12 +++++++++--- >> mm/migrate.c | 19 ++++++++++++------- >> 3 files changed, 23 insertions(+), 12 deletions(-) >> >> diff --git a/mm/huge_memory.c b/mm/huge_memory.c >> index 8a7c1b344abe..b2ba17c3dcd7 100644 >> --- a/mm/huge_memory.c >> +++ b/mm/huge_memory.c >> @@ -2963,10 +2963,10 @@ static int split_huge_pages_pid(int pid, unsigned long vaddr_start, >> /* FOLL_DUMP to ignore special (like zero) pages */ >> page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); >> >> - if (IS_ERR_OR_NULL(page) || is_zone_device_page(page)) >> + if (IS_ERR_OR_NULL(page)) >> continue; >> >> - if (!is_transparent_hugepage(page)) >> + if (is_zone_device_page(page) || !is_transparent_hugepage(page)) > > !is_transparent_hugepage should already do the work here? IIRC, zone_device_page can't be > a transhuge page anyway. And only transparent_hugepage is cared here. I agree. Can we avoid sending a new version of a patch series as reply to another patch series (previous version)? Acked-by: David Hildenbrand -- Thanks, David / dhildenb