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 CCD5622DFA5 for ; Thu, 9 Oct 2025 03:18:58 +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=1759979938; cv=none; b=sJRqhFigzBiLodkiYWi3y1ijdMORPogsew+gZxA1DACzXZ5/ten5lo/WeeCLoxuLxAubp52Qz2tMToxvSLK830yTzFrdx8yhpl2htIgDdxIYpgoIXMDww/42Xapiks2GhjLz9SWjmbhiAlhroX7V9XK3ZXWLW/GG74wl0qzjdJo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759979938; c=relaxed/simple; bh=S2ok4Vg6JA+akrkaTLaySzj226subkUvQkEDc8zWCfA=; h=Date:To:From:Subject:Message-Id; b=cIjRzVGgjHPG8Er9N7aBTl5o7y6D9N0/MlHBwE8EmVVmnWHVTw1mMMN9WK/KI2RRy2C55qKyMrDllN1oxk4Sf1fKvlTZph0izwiiqYRDyExVO9AvkGz4CSPvN4+XlX6VRx+fIoUXoeyXIUzpYGs7G5nDU4FnojxWEF/eMvZMnRA= 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=FzW/hhLl; 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="FzW/hhLl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 98F6BC4CEE7; Thu, 9 Oct 2025 03:18:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1759979938; bh=S2ok4Vg6JA+akrkaTLaySzj226subkUvQkEDc8zWCfA=; h=Date:To:From:Subject:From; b=FzW/hhLlUdc63S6i+SemFqd6Aq+0clwmN/lDr7tu450Ey4JFzWNORwow9CC3cBFz5 DT5EEpPrJno9aGQhOGdA818WmtqPPySAfIE/lrxiN/oa1TJx/RV9xvZ1AQG2hKk8/n AL8wjhd8DbR7WKdL+CFCXUcqWB0OAS6714YfyCco= Date: Wed, 08 Oct 2025 20:18:58 -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,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,balbirs@nvidia.com,apopple@nvidia.com,airlied@gmail.com,matthew.brost@intel.com,akpm@linux-foundation.org From: Andrew Morton Subject: + selftests-mm-hmm-tests-partial-unmap-mremap-and-anon_write-tests.patch added to mm-new branch Message-Id: <20251009031858.98F6BC4CEE7@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: selftests/mm/hmm-tests: partial unmap, mremap and anon_write tests has been added to the -mm mm-new branch. Its filename is selftests-mm-hmm-tests-partial-unmap-mremap-and-anon_write-tests.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-mm-hmm-tests-partial-unmap-mremap-and-anon_write-tests.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: Matthew Brost Subject: selftests/mm/hmm-tests: partial unmap, mremap and anon_write tests Date: Wed, 1 Oct 2025 16:57:05 +1000 Add partial unmap test case which munmaps memory while in the device. Add tests exercising mremap on faulted-in memory (CPU and GPU) at various offsets and verify correctness. Update anon_write_child to read device memory after fork verifying this flow works in the kernel. Both THP and non-THP cases are updated. Link: https://lkml.kernel.org/r/20251001065707.920170-15-balbirs@nvidia.com Signed-off-by: Balbir Singh Signed-off-by: Matthew Brost 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 --- tools/testing/selftests/mm/hmm-tests.c | 308 ++++++++++++++++++----- 1 file changed, 250 insertions(+), 58 deletions(-) --- a/tools/testing/selftests/mm/hmm-tests.c~selftests-mm-hmm-tests-partial-unmap-mremap-and-anon_write-tests +++ a/tools/testing/selftests/mm/hmm-tests.c @@ -50,6 +50,8 @@ enum { HMM_COHERENCE_DEVICE_TWO, }; +#define ONEKB (1 << 10) +#define ONEMEG (1 << 20) #define TWOMEG (1 << 21) #define HMM_BUFFER_SIZE (1024 << 12) #define HMM_PATH_MAX 64 @@ -525,6 +527,8 @@ TEST_F(hmm, anon_write_prot) /* * Check that a device writing an anonymous private mapping * will copy-on-write if a child process inherits the mapping. + * + * Also verifies after fork() memory the device can be read by child. */ TEST_F(hmm, anon_write_child) { @@ -532,72 +536,101 @@ TEST_F(hmm, anon_write_child) unsigned long npages; unsigned long size; unsigned long i; + void *old_ptr; + void *map; int *ptr; pid_t pid; int child_fd; - int ret; + int ret, use_thp, migrate; - npages = ALIGN(HMM_BUFFER_SIZE, self->page_size) >> self->page_shift; - ASSERT_NE(npages, 0); - size = npages << self->page_shift; + for (migrate = 0; migrate < 2; ++migrate) { + for (use_thp = 0; use_thp < 2; ++use_thp) { + npages = ALIGN(use_thp ? TWOMEG : HMM_BUFFER_SIZE, + self->page_size) >> self->page_shift; + ASSERT_NE(npages, 0); + size = npages << self->page_shift; + + buffer = malloc(sizeof(*buffer)); + ASSERT_NE(buffer, NULL); + + buffer->fd = -1; + buffer->size = size * 2; + buffer->mirror = malloc(size); + ASSERT_NE(buffer->mirror, NULL); + + buffer->ptr = mmap(NULL, size * 2, + PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, + buffer->fd, 0); + ASSERT_NE(buffer->ptr, MAP_FAILED); + + old_ptr = buffer->ptr; + if (use_thp) { + map = (void *)ALIGN((uintptr_t)buffer->ptr, size); + ret = madvise(map, size, MADV_HUGEPAGE); + ASSERT_EQ(ret, 0); + buffer->ptr = map; + } + + /* Initialize buffer->ptr so we can tell if it is written. */ + for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i) + ptr[i] = i; + + /* Initialize data that the device will write to buffer->ptr. */ + for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i) + ptr[i] = -i; + + if (migrate) { + ret = hmm_migrate_sys_to_dev(self->fd, buffer, npages); + ASSERT_EQ(ret, 0); + ASSERT_EQ(buffer->cpages, npages); + + } + + pid = fork(); + if (pid == -1) + ASSERT_EQ(pid, 0); + if (pid != 0) { + waitpid(pid, &ret, 0); + ASSERT_EQ(WIFEXITED(ret), 1); + + /* Check that the parent's buffer did not change. */ + for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i) + ASSERT_EQ(ptr[i], i); + + buffer->ptr = old_ptr; + hmm_buffer_free(buffer); + continue; + } + + /* Check that we see the parent's values. */ + for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i) + ASSERT_EQ(ptr[i], i); + if (!migrate) { + for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i) + ASSERT_EQ(ptr[i], -i); + } + + /* The child process needs its own mirror to its own mm. */ + child_fd = hmm_open(0); + ASSERT_GE(child_fd, 0); - buffer = malloc(sizeof(*buffer)); - ASSERT_NE(buffer, NULL); - - buffer->fd = -1; - buffer->size = size; - buffer->mirror = malloc(size); - ASSERT_NE(buffer->mirror, NULL); - - buffer->ptr = mmap(NULL, size, - PROT_READ | PROT_WRITE, - MAP_PRIVATE | MAP_ANONYMOUS, - buffer->fd, 0); - ASSERT_NE(buffer->ptr, MAP_FAILED); - - /* Initialize buffer->ptr so we can tell if it is written. */ - for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i) - ptr[i] = i; - - /* Initialize data that the device will write to buffer->ptr. */ - for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i) - ptr[i] = -i; + /* Simulate a device writing system memory. */ + ret = hmm_dmirror_cmd(child_fd, HMM_DMIRROR_WRITE, buffer, npages); + ASSERT_EQ(ret, 0); + ASSERT_EQ(buffer->cpages, npages); + ASSERT_EQ(buffer->faults, 1); - pid = fork(); - if (pid == -1) - ASSERT_EQ(pid, 0); - if (pid != 0) { - waitpid(pid, &ret, 0); - ASSERT_EQ(WIFEXITED(ret), 1); + /* Check what the device wrote. */ + if (!migrate) { + for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i) + ASSERT_EQ(ptr[i], -i); + } - /* Check that the parent's buffer did not change. */ - for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i) - ASSERT_EQ(ptr[i], i); - return; + close(child_fd); + exit(0); + } } - - /* Check that we see the parent's values. */ - for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i) - ASSERT_EQ(ptr[i], i); - for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i) - ASSERT_EQ(ptr[i], -i); - - /* The child process needs its own mirror to its own mm. */ - child_fd = hmm_open(0); - ASSERT_GE(child_fd, 0); - - /* Simulate a device writing system memory. */ - ret = hmm_dmirror_cmd(child_fd, HMM_DMIRROR_WRITE, buffer, npages); - ASSERT_EQ(ret, 0); - ASSERT_EQ(buffer->cpages, npages); - ASSERT_EQ(buffer->faults, 1); - - /* Check what the device wrote. */ - for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i) - ASSERT_EQ(ptr[i], -i); - - close(child_fd); - exit(0); } /* @@ -2290,6 +2323,165 @@ TEST_F(hmm, migrate_anon_huge_fault) } /* + * Migrate memory and fault back to sysmem after partially unmapping. + */ +TEST_F(hmm, migrate_partial_unmap_fault) +{ + struct hmm_buffer *buffer; + unsigned long npages; + unsigned long size = TWOMEG; + unsigned long i; + void *old_ptr; + void *map; + int *ptr; + int ret, j, use_thp; + int offsets[] = { 0, 512 * ONEKB, ONEMEG }; + + for (use_thp = 0; use_thp < 2; ++use_thp) { + for (j = 0; j < ARRAY_SIZE(offsets); ++j) { + buffer = malloc(sizeof(*buffer)); + ASSERT_NE(buffer, NULL); + + buffer->fd = -1; + buffer->size = 2 * size; + buffer->mirror = malloc(size); + ASSERT_NE(buffer->mirror, NULL); + memset(buffer->mirror, 0xFF, size); + + buffer->ptr = mmap(NULL, 2 * size, + PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, + buffer->fd, 0); + ASSERT_NE(buffer->ptr, MAP_FAILED); + + npages = size >> self->page_shift; + map = (void *)ALIGN((uintptr_t)buffer->ptr, size); + if (use_thp) + ret = madvise(map, size, MADV_HUGEPAGE); + else + ret = madvise(map, size, MADV_NOHUGEPAGE); + ASSERT_EQ(ret, 0); + old_ptr = buffer->ptr; + buffer->ptr = map; + + /* Initialize buffer in system memory. */ + for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i) + ptr[i] = i; + + /* Migrate memory to device. */ + ret = hmm_migrate_sys_to_dev(self->fd, buffer, npages); + ASSERT_EQ(ret, 0); + ASSERT_EQ(buffer->cpages, npages); + + /* Check what the device read. */ + for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i) + ASSERT_EQ(ptr[i], i); + + munmap(buffer->ptr + offsets[j], ONEMEG); + + /* Fault pages back to system memory and check them. */ + for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i) + if (i * sizeof(int) < offsets[j] || + i * sizeof(int) >= offsets[j] + ONEMEG) + ASSERT_EQ(ptr[i], i); + + buffer->ptr = old_ptr; + hmm_buffer_free(buffer); + } + } +} + +TEST_F(hmm, migrate_remap_fault) +{ + struct hmm_buffer *buffer; + unsigned long npages; + unsigned long size = TWOMEG; + unsigned long i; + void *old_ptr, *new_ptr = NULL; + void *map; + int *ptr; + int ret, j, use_thp, dont_unmap, before; + int offsets[] = { 0, 512 * ONEKB, ONEMEG }; + + for (before = 0; before < 2; ++before) { + for (dont_unmap = 0; dont_unmap < 2; ++dont_unmap) { + for (use_thp = 0; use_thp < 2; ++use_thp) { + for (j = 0; j < ARRAY_SIZE(offsets); ++j) { + int flags = MREMAP_MAYMOVE | MREMAP_FIXED; + + if (dont_unmap) + flags |= MREMAP_DONTUNMAP; + + buffer = malloc(sizeof(*buffer)); + ASSERT_NE(buffer, NULL); + + buffer->fd = -1; + buffer->size = 8 * size; + buffer->mirror = malloc(size); + ASSERT_NE(buffer->mirror, NULL); + memset(buffer->mirror, 0xFF, size); + + buffer->ptr = mmap(NULL, buffer->size, + PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, + buffer->fd, 0); + ASSERT_NE(buffer->ptr, MAP_FAILED); + + npages = size >> self->page_shift; + map = (void *)ALIGN((uintptr_t)buffer->ptr, size); + if (use_thp) + ret = madvise(map, size, MADV_HUGEPAGE); + else + ret = madvise(map, size, MADV_NOHUGEPAGE); + ASSERT_EQ(ret, 0); + old_ptr = buffer->ptr; + munmap(map + size, size * 2); + buffer->ptr = map; + + /* Initialize buffer in system memory. */ + for (i = 0, ptr = buffer->ptr; + i < size / sizeof(*ptr); ++i) + ptr[i] = i; + + if (before) { + new_ptr = mremap((void *)map, size, size, flags, + map + size + offsets[j]); + ASSERT_NE(new_ptr, MAP_FAILED); + buffer->ptr = new_ptr; + } + + /* Migrate memory to device. */ + ret = hmm_migrate_sys_to_dev(self->fd, buffer, npages); + ASSERT_EQ(ret, 0); + ASSERT_EQ(buffer->cpages, npages); + + /* Check what the device read. */ + for (i = 0, ptr = buffer->mirror; + i < size / sizeof(*ptr); ++i) + ASSERT_EQ(ptr[i], i); + + if (!before) { + new_ptr = mremap((void *)map, size, size, flags, + map + size + offsets[j]); + ASSERT_NE(new_ptr, MAP_FAILED); + buffer->ptr = new_ptr; + } + + /* Fault pages back to system memory and check them. */ + for (i = 0, ptr = buffer->ptr; + i < size / sizeof(*ptr); ++i) + ASSERT_EQ(ptr[i], i); + + munmap(new_ptr, size); + buffer->ptr = old_ptr; + hmm_buffer_free(buffer); + } + } + } + } +} + +/* * Migrate private anonymous huge page with allocation errors. */ TEST_F(hmm, migrate_anon_huge_err) _ Patches currently in -mm which might be from matthew.brost@intel.com are selftests-mm-hmm-tests-partial-unmap-mremap-and-anon_write-tests.patch