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Fri, 6 Nov 2026 17:08:50 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.87.85.9]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTP; Fri, 6 Nov 2026 17:08:50 +0000 (GMT) From: Gerald Schaefer To: linux-s390 Cc: Alexander Gordeev , Heiko Carstens , Christian Borntraeger , Ilya Leoshkevich Subject: [PATCH] s390/mm: Allow hugepage migration for s390 Date: Fri, 6 Nov 2026 18:08:44 +0100 Message-ID: <20261106170844.4079771-1-gerald.schaefer@linux.ibm.com> X-Mailer: git-send-email 2.53.0 X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Info: AW1haW4tMjYxMTA2MDA2NiBTYWx0ZWRfX+z2RZhqjS1ms zZOWHZyY0vUdXNHfhcMp+4/UH1/BUBe0ZzD3+2sKZhqb+vuhhgNilHds1NAC7rQ15EN4onHlZu/ cLJYQtMQEr6uSUnq5RhM9dhsL6Zf3I4= X-Proofpoint-GUID: slRozmJO34dxtVcBMloIBqrVbHG8kGFx X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMTA2MDA2NiBTYWx0ZWRfX6VuNbmzFFfNp AAiXXJbSjcIqiksDFHbFK/JgjhbzMYVFmbvtx4j5uJnobMp5Yq6xGR4+gPMJE7go2SjOGKeR1Y/ aELkBOG4pnbgo7XO8FUwenEaRYqVkplyXIFyb8h+Gz2fWdh3/zjZ//9D2RTSUhHvaNUTEpkb1Jp FETAHaLvA6Ii8Oc2sfRl11mzaxTvM2taWYTWdlHdNMpVxbLps2tLyouMNxZEmsPnPyQ9wWZ5cnL IOT5KdC4GyhwZkZyqmv7C/SljGGpbtksgHB/J4AWxbWcUIxaqnrNGdovZ4NoCqk/0+zYntOubqg 1o+9+Mgs5iB3TDLJ+pyBbQRPSnnoD0CSDtXGveEXcTX6m72VI52GeTL0UWxe9SZc2o37WPiFgTg rUbek9Ka5wvVstjiKxgVlby+mvD5KARJXm8bbUZMQgCDvNyfBdRe4uv+eQdXNK2CSBDZuqKozuV G8H7BWdvnTdlTG1iqpQ== X-Proofpoint-ORIG-GUID: slRozmJO34dxtVcBMloIBqrVbHG8kGFx X-Authority-Analysis: v=2.4 cv=CY+dd7rl c=1 sm=1 tr=0 ts=6aee09a7 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=zJRp6_cAMcgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=VnNF1IyMAAAA:8 a=dqShpuBjQzf0R5tXLcIA:9 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.138,FMLib:17.12.100.49 definitions=2026-11-06_05,2026-11-06_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 suspectscore=0 bulkscore=0 phishscore=0 impostorscore=0 malwarescore=0 lowpriorityscore=0 spamscore=0 clxscore=1015 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2611040001 definitions=main-2611060066 After hugetlbfs PTE_MARKER support for s390 introduced region-third and segment table swap entries, it is possible to also allow hugepage migration for s390. This fixes the problem that hugetlbfs pages could not be allocated from ZONE_MOVABLE memory, which is often used in combination with memory hotplug. Therefore, without support for hugepage migration, a large portion of system memory could be unavailable for hugetlbfs page allocations. Besides selecting ARCH_ENABLE_HUGEPAGE_MIGRATION, this only requires definition of arch_hugetlb_migration_supported(), which can make use of the existing arch_hugetlb_valid_size() function, similar to other architectures. Signed-off-by: Gerald Schaefer --- arch/s390/Kconfig | 1 + arch/s390/include/asm/hugetlb.h | 5 +++++ arch/s390/mm/hugetlbpage.c | 14 +++++++++++++- 3 files changed, 19 insertions(+), 1 deletion(-) diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 612885228824..e3a704f423f3 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -83,6 +83,7 @@ config S390 select ALTERNATE_USER_ADDRESS_SPACE select ARCH_32BIT_USTAT_F_TINODE select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE + select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION select ARCH_ENABLE_MEMORY_HOTPLUG if SPARSEMEM select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2 select ARCH_HAS_PMD_SOFTLEAVES if TRANSPARENT_HUGEPAGE diff --git a/arch/s390/include/asm/hugetlb.h b/arch/s390/include/asm/hugetlb.h index aea754b67c89..356a18a75d99 100644 --- a/arch/s390/include/asm/hugetlb.h +++ b/arch/s390/include/asm/hugetlb.h @@ -17,6 +17,11 @@ #define hugepages_supported() cpu_has_edat1() +#ifdef CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION +bool arch_hugetlb_migration_supported(struct hstate *h); +#define arch_hugetlb_migration_supported arch_hugetlb_migration_supported +#endif + #define __HAVE_ARCH_HUGE_SET_HUGE_PTE_AT void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pte, unsigned long sz); diff --git a/arch/s390/mm/hugetlbpage.c b/arch/s390/mm/hugetlbpage.c index f84aa9265430..ce61f8738465 100644 --- a/arch/s390/mm/hugetlbpage.c +++ b/arch/s390/mm/hugetlbpage.c @@ -224,7 +224,7 @@ pte_t *huge_pte_offset(struct mm_struct *mm, return (pte_t *) pmdp; } -bool __init arch_hugetlb_valid_size(unsigned long size) +static bool __hugetlb_valid_size(unsigned long size) { if (cpu_has_edat1() && size == PMD_SIZE) return true; @@ -241,3 +241,15 @@ unsigned int __init arch_hugetlb_cma_order(void) return 0; } + +bool __init arch_hugetlb_valid_size(unsigned long size) +{ + return __hugetlb_valid_size(size); +} + +#ifdef CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION +bool arch_hugetlb_migration_supported(struct hstate *h) +{ + return __hugetlb_valid_size(huge_page_size(h)); +} +#endif -- 2.53.0