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b=n4Cs8gaQvD83o2GnKHcSBRyUMTmI299u5BVS369CgFHyVH0hy3awrGVyT27raqlv7 99XZqYrnJh0AB0L3yHawhlhEeH5EFHLYEjR96eQMVTAA0pxjE0lIqd146w0gMwVz40 LvJNEgWKZCUKWAEMMyl07GxSD9EXkNgBhqCzFLAhaZ5R5A5buN5MjcyZTFUtPqjZ9m Ifp2L5iyHs1DaWr8fnDY7FZqY9D+cOHd6OFp5fyrhR8H6hBYNmldTsT8hodrFbL7vZ 7jYT2zSzLRoSdf+icjC2k64jDgU1bsg7k9BYfDJmcbxWlvdfa4rmy02vXdDe8igHZZ bUdftY2rnB3XA== Message-ID: Date: Fri, 27 Feb 2026 21:50:15 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 4/4] page_reporting: change PAGE_REPORTING_DEFAULT_ORDER to -1 To: Yuvraj Sakshith , akpm@linux-foundation.org Cc: mst@redhat.com, kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, longli@microsoft.com, jasowang@redhat.com, xuanzhuo@linux.alibaba.com, eperezma@redhat.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, jackmanb@google.com, hannes@cmpxchg.org, ziy@nvidia.com, linux-hyperv@vger.kernel.org, virtualization@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260227140655.360696-1-yuvraj.sakshith@oss.qualcomm.com> <20260227140655.360696-5-yuvraj.sakshith@oss.qualcomm.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: E30C0A000B X-Stat-Signature: i38cdmq937mnpy35i8pnh6ykcxuedqhq X-Rspam-User: X-HE-Tag: 1772225423-362660 X-HE-Meta: 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2/27/26 15:06, Yuvraj Sakshith wrote: > PAGE_REPORTING_DEFAULT_ORDER is now set to zero. This means, > pages of order zero cannot be reported to a client/driver -- as zero > is used to signal a fallback to MAX_PAGE_ORDER. > > Change PAGE_REPORTING_DEFAULT_ORDER to (-1), > so that zero can be used as a valid order with which pages can > be reported. > > Signed-off-by: Yuvraj Sakshith > --- > include/linux/page_reporting.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/page_reporting.h b/include/linux/page_reporting.h > index a7e3e30f2..3eb3e26d8 100644 > --- a/include/linux/page_reporting.h > +++ b/include/linux/page_reporting.h > @@ -7,7 +7,7 @@ > > /* This value should always be a power of 2, see page_reporting_cycle() */ > #define PAGE_REPORTING_CAPACITY 32 > -#define PAGE_REPORTING_DEFAULT_ORDER 0 > +#define PAGE_REPORTING_DEFAULT_ORDER (-1) No need for the (). Wondering whether we now also want to do in this patch: diff --git a/mm/page_reporting.c b/mm/page_reporting.c index f0042d5743af..d432aadf9d07 100644 --- a/mm/page_reporting.c +++ b/mm/page_reporting.c @@ -11,8 +11,7 @@ #include "page_reporting.h" #include "internal.h" -/* Initialize to an unsupported value */ -unsigned int page_reporting_order = -1; +unsigned int page_reporting_order = PAGE_REPORTING_DEFAULT_ORDER; static int page_order_update_notify(const char *val, const struct kernel_param *kp) { @@ -369,7 +368,7 @@ int page_reporting_register(struct page_reporting_dev_info *prdev) * pageblock_order. */ - if (page_reporting_order == -1) { + if (page_reporting_order == PAGE_REPORTING_DEFAULT_ORDER) { (and wondering whether we should have called it PAGE_REPORTING_USE_DEFAULT_ORDER to make it clearer that it is not an actual order. Leaving that up to you :) ) -- Cheers, David