From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1846AD515 for ; Tue, 9 Sep 2025 04:00:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757390457; cv=none; b=skQ5VnVph3cA2t7oiqt6bg/taRlcV3pwyg/aJAxDWM1H0+7db1mLVSw3HrF/xwNnzoLPePcgfbwV7rBOwoH/7F5p8IgOF3h8O/VCI0JeejU5os7aU6Q+yB0k/39R6mlui2yFtuBEFtkTwQyqZuTlIrO/Wgt3Ulza961FY4s6xxI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757390457; c=relaxed/simple; bh=GIdHo6vMl6Gk/eJmeo5I1iwigijdkq9et36x0I9+KQQ=; h=Date:To:From:Subject:Message-Id; b=hDHXcPgNbl/+WxNZXwbeKFF98XvA1MA/HDiYFN9PaaItxcU299JFq2RxkNdKp8Tsw4qAyUwZLqrUgdq9DyzjWBXsl/ptna8flugqaLXJDZL6IQN0KqwmGI0cG8+Io3RXK7ZSRyfvNu6YoKmq0ei6H9pKk6NKgdxnMZKHvNTpe+Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=p//+0kjC; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="p//+0kjC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AAE06C4CEF4; Tue, 9 Sep 2025 04:00:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1757390456; bh=GIdHo6vMl6Gk/eJmeo5I1iwigijdkq9et36x0I9+KQQ=; h=Date:To:From:Subject:From; b=p//+0kjCmUV/nWOZtxXOqlL5S5mL7N2zE6MGKMmDrtNzVPxNZgrDiKlpaVdybeQF+ YursJOZvJcXfET1m7Zsptt040RG5sx+4dWAaDbCfVeoWgKoC/M1iU13J0DY5ki5U7i 4xWzcYjv7ppaVr94XAnlRw+QMnmsIJt0+ghpOmVU= Date: Mon, 08 Sep 2025 21:00:56 -0700 To: mm-commits@vger.kernel.org,ziy@nvidia.com,ying.huang@linux.alibaba.com,simona@ffwll.ch,ryan.roberts@arm.com,rcampbell@nvidia.com,rakie.kim@sk.com,osalvador@suse.de,npache@redhat.com,mpenttil@redhat.com,matthew.brost@intel.com,lyude@redhat.com,lorenzo.stoakes@oracle.com,Liam.Howlett@oracle.com,joshua.hahnjy@gmail.com,gourry@gourry.net,francois.dugast@intel.com,dev.jain@arm.com,david@redhat.com,dakr@kernel.org,byungchul@sk.com,baolin.wang@linux.alibaba.com,baohua@kernel.org,apopple@nvidia.com,airlied@gmail.com,balbirs@nvidia.com,akpm@linux-foundation.org From: Andrew Morton Subject: + lib-test_hmm-add-large-page-allocation-failure-testing.patch added to mm-new branch Message-Id: <20250909040056.AAE06C4CEF4@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: lib/test_hmm: add large page allocation failure testing has been added to the -mm mm-new branch. Its filename is lib-test_hmm-add-large-page-allocation-failure-testing.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/lib-test_hmm-add-large-page-allocation-failure-testing.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Balbir Singh Subject: lib/test_hmm: add large page allocation failure testing Date: Mon, 8 Sep 2025 10:04:44 +1000 Add HMM_DMIRROR_FLAG_FAIL_ALLOC flag to simulate large page allocation failures, enabling testing of split migration code paths. This test flag allows validation of the fallback behavior when destination device cannot allocate compound pages. This is useful for testing the split migration functionality. Link: https://lkml.kernel.org/r/20250908000448.180088-12-balbirs@nvidia.com Signed-off-by: Balbir Singh Cc: David Hildenbrand Cc: Zi Yan Cc: Joshua Hahn Cc: Rakie Kim Cc: Byungchul Park Cc: Gregory Price Cc: Ying Huang Cc: Alistair Popple Cc: Oscar Salvador Cc: Lorenzo Stoakes Cc: Baolin Wang Cc: "Liam R. Howlett" Cc: Nico Pache Cc: Ryan Roberts Cc: Dev Jain Cc: Barry Song Cc: Lyude Paul Cc: Danilo Krummrich Cc: David Airlie Cc: Simona Vetter Cc: Ralph Campbell Cc: Mika Penttilä Cc: Matthew Brost Cc: Francois Dugast Signed-off-by: Andrew Morton --- lib/test_hmm.c | 61 ++++++++++++++++++++++++++++-------------- lib/test_hmm_uapi.h | 3 ++ 2 files changed, 44 insertions(+), 20 deletions(-) --- a/lib/test_hmm.c~lib-test_hmm-add-large-page-allocation-failure-testing +++ a/lib/test_hmm.c @@ -92,6 +92,7 @@ struct dmirror { struct xarray pt; struct mmu_interval_notifier notifier; struct mutex mutex; + __u64 flags; }; /* @@ -699,7 +700,12 @@ static void dmirror_migrate_alloc_and_co page_to_pfn(spage))) goto next; - dpage = dmirror_devmem_alloc_page(dmirror, is_large); + if (dmirror->flags & HMM_DMIRROR_FLAG_FAIL_ALLOC) { + dmirror->flags &= ~HMM_DMIRROR_FLAG_FAIL_ALLOC; + dpage = NULL; + } else + dpage = dmirror_devmem_alloc_page(dmirror, is_large); + if (!dpage) { struct folio *folio; unsigned long i; @@ -959,44 +965,55 @@ static vm_fault_t dmirror_devmem_fault_a spage = BACKING_PAGE(spage); order = folio_order(page_folio(spage)); - if (order) + *dst = MIGRATE_PFN_COMPOUND; + if (*src & MIGRATE_PFN_WRITE) + *dst |= MIGRATE_PFN_WRITE; + + if (dmirror->flags & HMM_DMIRROR_FLAG_FAIL_ALLOC) { + dmirror->flags &= ~HMM_DMIRROR_FLAG_FAIL_ALLOC; + *dst &= ~MIGRATE_PFN_COMPOUND; + dpage = NULL; + } else if (order) { dpage = folio_page(vma_alloc_folio(GFP_HIGHUSER_MOVABLE, order, args->vma, addr), 0); - else - dpage = alloc_page_vma(GFP_HIGHUSER_MOVABLE, args->vma, addr); - - /* Try with smaller pages if large allocation fails */ - if (!dpage && order) { + } else { dpage = alloc_page_vma(GFP_HIGHUSER_MOVABLE, args->vma, addr); - if (!dpage) - return VM_FAULT_OOM; - order = 0; } + if (!dpage && !order) + return VM_FAULT_OOM; + pr_debug("migrating from sys to dev pfn src: 0x%lx pfn dst: 0x%lx\n", page_to_pfn(spage), page_to_pfn(dpage)); - lock_page(dpage); - xa_erase(&dmirror->pt, addr >> PAGE_SHIFT); - copy_highpage(dpage, spage); - *dst = migrate_pfn(page_to_pfn(dpage)); - if (*src & MIGRATE_PFN_WRITE) - *dst |= MIGRATE_PFN_WRITE; - if (order) - *dst |= MIGRATE_PFN_COMPOUND; + + if (dpage) { + lock_page(dpage); + *dst |= migrate_pfn(page_to_pfn(dpage)); + } for (i = 0; i < (1 << order); i++) { struct page *src_page; struct page *dst_page; + /* Try with smaller pages if large allocation fails */ + if (!dpage && order) { + dpage = alloc_page_vma(GFP_HIGHUSER_MOVABLE, args->vma, addr); + lock_page(dpage); + dst[i] = migrate_pfn(page_to_pfn(dpage)); + dst_page = pfn_to_page(page_to_pfn(dpage)); + dpage = NULL; /* For the next iteration */ + } else { + dst_page = pfn_to_page(page_to_pfn(dpage) + i); + } + src_page = pfn_to_page(page_to_pfn(spage) + i); - dst_page = pfn_to_page(page_to_pfn(dpage) + i); xa_erase(&dmirror->pt, addr >> PAGE_SHIFT); + addr += PAGE_SIZE; copy_highpage(dst_page, src_page); } next: - addr += PAGE_SIZE << order; src += 1 << order; dst += 1 << order; } @@ -1514,6 +1531,10 @@ static long dmirror_fops_unlocked_ioctl( dmirror_device_remove_chunks(dmirror->mdevice); ret = 0; break; + case HMM_DMIRROR_FLAGS: + dmirror->flags = cmd.npages; + ret = 0; + break; default: return -EINVAL; --- a/lib/test_hmm_uapi.h~lib-test_hmm-add-large-page-allocation-failure-testing +++ a/lib/test_hmm_uapi.h @@ -37,6 +37,9 @@ struct hmm_dmirror_cmd { #define HMM_DMIRROR_EXCLUSIVE _IOWR('H', 0x05, struct hmm_dmirror_cmd) #define HMM_DMIRROR_CHECK_EXCLUSIVE _IOWR('H', 0x06, struct hmm_dmirror_cmd) #define HMM_DMIRROR_RELEASE _IOWR('H', 0x07, struct hmm_dmirror_cmd) +#define HMM_DMIRROR_FLAGS _IOWR('H', 0x08, struct hmm_dmirror_cmd) + +#define HMM_DMIRROR_FLAG_FAIL_ALLOC (1ULL << 0) /* * Values returned in hmm_dmirror_cmd.ptr for HMM_DMIRROR_SNAPSHOT. _ Patches currently in -mm which might be from balbirs@nvidia.com are mm-zone_device-support-large-zone-device-private-folios.patch mm-huge_memory-add-device-private-thp-support-to-pmd-operations.patch mm-rmap-extend-rmap-and-migration-support-device-private-entries.patch mm-huge_memory-implement-device-private-thp-splitting.patch mm-migrate_device-handle-partially-mapped-folios-during-collection.patch mm-migrate_device-implement-thp-migration-of-zone-device-pages.patch mm-memory-fault-add-thp-fault-handling-for-zone-device-private-pages.patch lib-test_hmm-add-zone-device-private-thp-test-infrastructure.patch mm-memremap-add-driver-callback-support-for-folio-splitting.patch mm-migrate_device-add-thp-splitting-during-migration.patch lib-test_hmm-add-large-page-allocation-failure-testing.patch selftests-mm-hmm-tests-new-tests-for-zone-device-thp-migration.patch selftests-mm-hmm-tests-new-throughput-tests-including-thp.patch gpu-drm-nouveau-enable-thp-support-for-gpu-memory-migration.patch