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[99.254.144.39]) by smtp.gmail.com with ESMTPSA id et15-20020a056214176f00b0065896b9fb15sm150399qvb.29.2023.10.12.15.29.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Oct 2023 15:29:33 -0700 (PDT) Date: Thu, 12 Oct 2023 18:29:30 -0400 From: Peter Xu To: Suren Baghdasaryan Cc: akpm@linux-foundation.org, viro@zeniv.linux.org.uk, brauner@kernel.org, shuah@kernel.org, aarcange@redhat.com, lokeshgidra@google.com, david@redhat.com, hughd@google.com, mhocko@suse.com, axelrasmussen@google.com, rppt@kernel.org, willy@infradead.org, Liam.Howlett@oracle.com, jannh@google.com, zhangpeng362@huawei.com, bgeffon@google.com, kaleshsingh@google.com, ngeoffray@google.com, jdduke@google.com, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, kernel-team@android.com Subject: Re: [PATCH v3 3/3] selftests/mm: add UFFDIO_MOVE ioctl test Message-ID: References: <20231009064230.2952396-1-surenb@google.com> <20231009064230.2952396-4-surenb@google.com> MIME-Version: 1.0 In-Reply-To: <20231009064230.2952396-4-surenb@google.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 652591C0013 X-Stat-Signature: rspkmptax37ia4yrwt8zrre71roptgn6 X-Rspam-User: X-HE-Tag: 1697149779-458818 X-HE-Meta: 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 VY91sdcf RFt/rG4R/R66MDKyMVSUvKL/3j1m8pryeGSGoEolBZ267Wn/oNGTS24fhJ3b+TMtUF1A00CCK/0I9xoRoDRtE2ilDpRjJA0C5TQEh2f7SVfc3jP8NzlP2zN6CsJr9Xj2xgxwE97Zlzwsa8Wyz1RruavviCMoKiWRn5mhrUK+8bZ+6JyvwDVEYCt4/fd9dUauVUppSa/Dv8dx0OZd35D0x5VFbDD/REfCyFWqqRRJGytpgZG7SJJz8JykQrTd9ZfZiOspO2uQMIBc4w02GBEeVr3KCKkpZEszxHwJpto6GI3xnPkTQmC44CXmeA74MbzGYcvDE7ZLzco/clSbtezX3JbinsiUq+Bk1fXrXqDWyaiYFQg2X017PPVdWTJcQoNDjplv1/DjDSz16tj1BE+yyuTn26eD8zOWl3liazY7ZvqBs/OGcr4s1Nakkxg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sun, Oct 08, 2023 at 11:42:28PM -0700, Suren Baghdasaryan wrote: > Add a test for new UFFDIO_MOVE ioctl which uses uffd to move source > into destination buffer while checking the contents of both after > remapping. After the operation the content of the destination buffer > should match the original source buffer's content while the source > buffer should be zeroed. > > Signed-off-by: Suren Baghdasaryan > --- > tools/testing/selftests/mm/uffd-common.c | 41 ++++++++++++- > tools/testing/selftests/mm/uffd-common.h | 1 + > tools/testing/selftests/mm/uffd-unit-tests.c | 62 ++++++++++++++++++++ > 3 files changed, 102 insertions(+), 2 deletions(-) > > diff --git a/tools/testing/selftests/mm/uffd-common.c b/tools/testing/selftests/mm/uffd-common.c > index 02b89860e193..ecc1244f1c2b 100644 > --- a/tools/testing/selftests/mm/uffd-common.c > +++ b/tools/testing/selftests/mm/uffd-common.c > @@ -52,6 +52,13 @@ static int anon_allocate_area(void **alloc_area, bool is_src) > *alloc_area = NULL; > return -errno; > } > + > + /* Prevent source pages from collapsing into THPs */ > + if (madvise(*alloc_area, nr_pages * page_size, MADV_NOHUGEPAGE)) { > + *alloc_area = NULL; > + return -errno; > + } Can we move this to test specific code? > + > return 0; > } > > @@ -484,8 +491,14 @@ void uffd_handle_page_fault(struct uffd_msg *msg, struct uffd_args *args) > offset = (char *)(unsigned long)msg->arg.pagefault.address - area_dst; > offset &= ~(page_size-1); > > - if (copy_page(uffd, offset, args->apply_wp)) > - args->missing_faults++; > + /* UFFD_MOVE is supported for anon non-shared mappings. */ > + if (uffd_test_ops == &anon_uffd_test_ops && !map_shared) { IIUC this means move_page() will start to run on many other tests... as long as anonymous & private. Probably not wanted, because not all tests may need this MOVE test, and it also means UFFDIO_COPY is never tested on anonymous.. You can overwrite uffd_args.handle_fault(). Axel just added a hook which seems also usable here. See 99aa77215ad02. > + if (move_page(uffd, offset)) > + args->missing_faults++; > + } else { > + if (copy_page(uffd, offset, args->apply_wp)) > + args->missing_faults++; > + } > } > } > > @@ -620,6 +633,30 @@ int copy_page(int ufd, unsigned long offset, bool wp) > return __copy_page(ufd, offset, false, wp); > } > > +int move_page(int ufd, unsigned long offset) > +{ > + struct uffdio_move uffdio_move; > + > + if (offset >= nr_pages * page_size) > + err("unexpected offset %lu\n", offset); > + uffdio_move.dst = (unsigned long) area_dst + offset; > + uffdio_move.src = (unsigned long) area_src + offset; > + uffdio_move.len = page_size; > + uffdio_move.mode = UFFDIO_MOVE_MODE_ALLOW_SRC_HOLES; > + uffdio_move.move = 0; > + if (ioctl(ufd, UFFDIO_MOVE, &uffdio_move)) { > + /* real retval in uffdio_move.move */ > + if (uffdio_move.move != -EEXIST) > + err("UFFDIO_MOVE error: %"PRId64, > + (int64_t)uffdio_move.move); > + wake_range(ufd, uffdio_move.dst, page_size); > + } else if (uffdio_move.move != page_size) { > + err("UFFDIO_MOVE error: %"PRId64, (int64_t)uffdio_move.move); > + } else > + return 1; > + return 0; > +} > + > int uffd_open_dev(unsigned int flags) > { > int fd, uffd; > diff --git a/tools/testing/selftests/mm/uffd-common.h b/tools/testing/selftests/mm/uffd-common.h > index 7c4fa964c3b0..f4d79e169a3d 100644 > --- a/tools/testing/selftests/mm/uffd-common.h > +++ b/tools/testing/selftests/mm/uffd-common.h > @@ -111,6 +111,7 @@ void wp_range(int ufd, __u64 start, __u64 len, bool wp); > void uffd_handle_page_fault(struct uffd_msg *msg, struct uffd_args *args); > int __copy_page(int ufd, unsigned long offset, bool retry, bool wp); > int copy_page(int ufd, unsigned long offset, bool wp); > +int move_page(int ufd, unsigned long offset); > void *uffd_poll_thread(void *arg); > > int uffd_open_dev(unsigned int flags); > diff --git a/tools/testing/selftests/mm/uffd-unit-tests.c b/tools/testing/selftests/mm/uffd-unit-tests.c > index 2709a34a39c5..f0ded3b34367 100644 > --- a/tools/testing/selftests/mm/uffd-unit-tests.c > +++ b/tools/testing/selftests/mm/uffd-unit-tests.c > @@ -824,6 +824,10 @@ static void uffd_events_test_common(bool wp) > char c; > struct uffd_args args = { 0 }; > > + /* Prevent source pages from being mapped more than once */ > + if (madvise(area_src, nr_pages * page_size, MADV_DONTFORK)) > + err("madvise(MADV_DONTFORK) failed"); Modifying events test is weird.. I assume you don't need this anymore after you switch to the handle_fault() hook. > + > fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK); > if (uffd_register(uffd, area_dst, nr_pages * page_size, > true, wp, false)) > @@ -1062,6 +1066,58 @@ static void uffd_poison_test(uffd_test_args_t *targs) > uffd_test_pass(); > } > > +static void uffd_move_test(uffd_test_args_t *targs) > +{ > + unsigned long nr; > + pthread_t uffd_mon; > + char c; > + unsigned long long count; > + struct uffd_args args = { 0 }; > + > + if (uffd_register(uffd, area_dst, nr_pages * page_size, > + true, false, false)) > + err("register failure"); > + > + if (pthread_create(&uffd_mon, NULL, uffd_poll_thread, &args)) > + err("uffd_poll_thread create"); > + > + /* > + * Read each of the pages back using the UFFD-registered mapping. We > + * expect that the first time we touch a page, it will result in a missing > + * fault. uffd_poll_thread will resolve the fault by remapping source > + * page to destination. > + */ > + for (nr = 0; nr < nr_pages; nr++) { > + /* Check area_src content */ > + count = *area_count(area_src, nr); > + if (count != count_verify[nr]) > + err("nr %lu source memory invalid %llu %llu\n", > + nr, count, count_verify[nr]); > + > + /* Faulting into area_dst should remap the page */ > + count = *area_count(area_dst, nr); > + if (count != count_verify[nr]) > + err("nr %lu memory corruption %llu %llu\n", > + nr, count, count_verify[nr]); > + > + /* Re-check area_src content which should be empty */ > + count = *area_count(area_src, nr); > + if (count != 0) > + err("nr %lu move failed %llu %llu\n", > + nr, count, count_verify[nr]); All of above should see zeros, right? Because I don't think anyone boosted the counter at all.. Maybe set some non-zero values to it? Then the re-check can make more sense. If you want, I think we can also make uffd-stress.c test to cover MOVE too, basically replacing all UFFDIO_COPY when e.g. user specified from cmdline. Optional, and may need some touch ups here and there, though. Thanks, > + } > + > + if (write(pipefd[1], &c, sizeof(c)) != sizeof(c)) > + err("pipe write"); > + if (pthread_join(uffd_mon, NULL)) > + err("join() failed"); > + > + if (args.missing_faults != nr_pages || args.minor_faults != 0) > + uffd_test_fail("stats check error"); > + else > + uffd_test_pass(); > +} > + > /* > * Test the returned uffdio_register.ioctls with different register modes. > * Note that _UFFDIO_ZEROPAGE is tested separately in the zeropage test. > @@ -1139,6 +1195,12 @@ uffd_test_case_t uffd_tests[] = { > .mem_targets = MEM_ALL, > .uffd_feature_required = 0, > }, > + { > + .name = "move", > + .uffd_fn = uffd_move_test, > + .mem_targets = MEM_ANON, > + .uffd_feature_required = UFFD_FEATURE_MOVE, > + }, > { > .name = "wp-fork", > .uffd_fn = uffd_wp_fork_test, > -- > 2.42.0.609.gbb76f46606-goog > -- Peter Xu