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[2003:d8:2f15:6200:d485:1bcd:d708:f5df]) by smtp.gmail.com with UTF8SMTPSA id ffacd0b85a97d-3a1f58f3369sm19586020f8f.57.2025.05.14.04.15.48 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 14 May 2025 04:15:49 -0700 (PDT) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, virtualization@lists.linux.dev, David Hildenbrand , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , =?UTF-8?q?Eugenio=20P=C3=A9rez?= , Andrew Morton , Oscar Salvador , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , "Matthew Wilcox (Oracle)" Subject: [PATCH v1 2/2] mm/memory_hotplug: remove -EBUSY handling from scan_movable_pages() Date: Wed, 14 May 2025 13:15:44 +0200 Message-ID: <20250514111544.1012399-3-david@redhat.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250514111544.1012399-1-david@redhat.com> References: <20250514111544.1012399-1-david@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Now that we can reliably identify PageOffline() pages that allow for memory offlining in has_unmovable_pages(), start_isolate_page_range() will fail on PageOffline() pages that would prevent memory offlining, and we no longer have to detect them in scan_movable_pages() anymore. Note that the previous mechanism relied on MEM_GOING_OFFLINE, whereby we were not able to distinguish the types of PageOffline() before MEM_GOING_OFFLINE. Signed-off-by: David Hildenbrand --- mm/memory_hotplug.c | 16 +--------------- 1 file changed, 1 insertion(+), 15 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 0cc5537f234bb..beace5b695aee 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1743,13 +1743,11 @@ bool mhp_range_allowed(u64 start, u64 size, bool ne= ed_mapping) /* * Scan pfn range [start,end) to find movable/migratable pages (LRU pages, * non-lru movable pages and hugepages). Will skip over most unmovable - * pages (esp., pages that can be skipped when offlining), but bail out on - * definitely unmovable pages. + * pages (esp., pages that can be skipped when offlining). * * Returns: * 0 in case a movable page is found and movable_pfn was updated. * -ENOENT in case no movable page was found. - * -EBUSY in case a definitely unmovable page was found. */ static int scan_movable_pages(unsigned long start, unsigned long end, unsigned long *movable_pfn) @@ -1766,13 +1764,6 @@ static int scan_movable_pages(unsigned long start, u= nsigned long end, if (__PageMovable(page)) goto found; =20 - /* - * PageOffline() pages that are neither "movable" nor - * "skippable" prevent memory offlining. - */ - if (PageOffline(page) && !PageOfflineSkippable(page)) - return -EBUSY; - if (!PageHuge(page)) continue; folio =3D page_folio(page); @@ -2051,11 +2042,6 @@ int offline_pages(unsigned long start_pfn, unsigned = long nr_pages, } } while (!ret); =20 - if (ret !=3D -ENOENT) { - reason =3D "unmovable page"; - goto failed_removal_isolated; - } - /* * Dissolve free hugetlb folios in the memory block before doing * offlining actually in order to make hugetlbfs's object --=20 2.49.0