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Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <20230704093819.48443ca7789043a640c8a07a@linux-foundation.org> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.151.185] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected X-Stat-Signature: 44cgsay71d5u1yxbatwnh6nyn5hj5imj X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 2680FA0012 X-Rspam-User: X-HE-Tag: 1688521443-526706 X-HE-Meta: U2FsdGVkX19TAGMhEXrWhNwygJyk8ZLJiCrLinTBLTSHrIpKCLDor4LSUKpfSd3LHL3Dg5zif4fF8pfzCJtzWBETZU/2uqWgN1sn4VCaMYiZDfL8xrDVyOZbZdeciIFsFtCKMFKZKfl4hBEwCUpezMo8+cpHvjd0Og5TPAeFcmMqB07q0uuQumwAE1QZGyWMT34WJ1SPBH4aNZ3fRFAiT8dcc2uuFZMDfI1wkqRHErhZYApdLOIVeXqt4o0/tYCSSGtkljWbzKah1iQR1vdw+5oyX5GfoZq9MQwPbI0u45uJxg3sGS20nVKfgq5qrlTywpmcE739LCMtnpV0HY45SGwhE3gb4KuCqdyMBgJazmldMdRHH/Lel8KKvLMqPE5GaYd7CQ5bjVvGpFzXWiDt5R6hKJTR9lCrle9PuECHkHEB0OWxkXU4PMSLDvDjvhvFQAGj6vYp1kXZ5KzwMvWBo3sXUpp+Kb2GY0HBBMV4AMKnfp7W9lbrJMYlKQDoyLn7LAgSypRX8tS9qWxLgMCWxtdwMfowVkrG6Yr37qI7wkPMaaValIvxvUuJKNdQ0iMujFgPCS1M/Pbubmo4fJDs9L//2rKG4RO9DaYTxjo4IPANaU0aeUPj07ZJMiCH1z4qf1pDyZCqRJ9atV7wXj7A0tecYrN2BhI6UkAu6nHqIcM3IHpCLwg/Q7Tj+6lmAn+kWpri8CFvs9eO0+TKprgl4gzteFNtkUWu4LzlRW6ZGnSPpJx5Zo5WFigk5WZGqj4K/69sNa1GSFeeh4FGtz09DhFkkblOEkXWudI5LhWldI9mQc2AY/ey1s/VGjE+6Ko2DrDTs3phwvl8HJJPewZtxA5Mi0RUgNTSfkRV5HHCtxf1abecelskvSN9Hf/KJpwlvhspb+rMGo9prbOxEnaKNPcP799H9BM9VVkt0G4BQJNzLrrcgP0Ej+EWx9/gryYYCLyDViKnIGQrCbIAo3L 9qVUg+eB RtPJXkMWIvTLh0UEefwyM6UyqW4RAIJzTwCfcABjBkfP5A+9gFsXT3X9C8iLaWA0D94CdoXEmqKbQnKHxu5Yt1iJq/W8NBCqf2n4MSPNFqhUbEiEmb7zeh1Yc11xm4/Q8vGOyhmi+QM/WRM9GFmcQUGSsO+yuOM0l9MAfUtizqD/72qajglB3XQZ5+w/fm3CMHs+MNZsVLI3X2E7MNn79eY85tJk8my1a6SHbc3RJjdNcuE8pEKxYZ8bipbq+/hWfRDme18wWet4qF6Y= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 2023/7/5 0:38, Andrew Morton wrote: > On Tue, 4 Jul 2023 20:36:00 +0800 Miaohe Lin wrote: > >> On 2023/7/4 20:13, Matthew Wilcox wrote: >>> On Tue, Jul 04, 2023 at 07:18:23PM +0800, Miaohe Lin wrote: >>>> @@ -470,6 +470,8 @@ static int page_outside_zone_boundaries(struct zone *zone, struct page *page) >>>> sp = zone->spanned_pages; >>>> if (!zone_spans_pfn(zone, pfn)) >>>> ret = 1; >>>> + else >>>> + ret = 0; >>> >>> Surely 'ret = zone_spans_pfn(zone, pfn);' ? >> >> Do you mean 'ret = !zone_spans_pfn(zone, pfn);'? This format looks fine to me. >> >>> >>> Also, did you spot this by inspection or do you have a test-case or bug >>> report? Should this have a Fixes: tag? >> >> This is from code inspection. The race window should be really small thus hard to trigger >> in real world. And yes, it seems Fixes tag is a really ancient commit: >> >> Fixes: bdc8cb984576 ("[PATCH] memory hotplug locking: zone span seqlock") >> > > Thanks. I updated the changelog: > > : If pfn is outside zone boundaries in the first round, ret will be set to > : 1. But if pfn is changed to inside the zone boundaries in zone span > : seqretry path, ret is still set to 1 leading to false page outside zone > : error info. > : > : This is from code inspection. The race window should be really small thus > : hard to trigger in real world. > : > : Link: https://lkml.kernel.org/r/20230704111823.940331-1-linmiaohe@huawei.com > : Fixes: bdc8cb984576 ("[PATCH] memory hotplug locking: zone span seqlock") > > and I made the change suggested by Matthew: > > --- a/mm/page_alloc.c~mm-page_alloc-avoid-false-page-outside-zone-error-info-fix > +++ a/mm/page_alloc.c > @@ -468,10 +468,7 @@ static int page_outside_zone_boundaries( > seq = zone_span_seqbegin(zone); > start_pfn = zone->zone_start_pfn; > sp = zone->spanned_pages; > - if (!zone_spans_pfn(zone, pfn)) > - ret = 1; > - else > - ret = 0; > + ret = !zone_spans_pfn(zone, pfn); > } while (zone_span_seqretry(zone, seq)); These changes look good to me. Thanks for doing this.