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Mon, 23 Mar 2026 20:23:18 -0400 X-MC-Unique: vstC6UL_MOuRp4ndn0wrMA-1 X-Mimecast-MFC-AGG-ID: vstC6UL_MOuRp4ndn0wrMA_1774311795 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 224B4195609E; Tue, 24 Mar 2026 00:23:15 +0000 (UTC) Received: from gmail.com (unknown [10.72.112.53]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 13DDF1800361; Tue, 24 Mar 2026 00:23:04 +0000 (UTC) Date: Tue, 24 Mar 2026 08:23:00 +0800 From: Chunyu Hu To: "Lorenzo Stoakes (Oracle)" Cc: akpm@linux-foundation.org, david@kernel.org, shuah@kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, ziy@nvidia.com, baolin.wang@linux.alibaba.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev Subject: Re: [PATCH v5 3/6] selftests/mm: move write_file helper to vm_util Message-ID: References: <20260323151753.2576137-1-chuhu@redhat.com> <20260323151753.2576137-4-chuhu@redhat.com> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 X-Mimecast-MFC-PROC-ID: A2wAGOa6HG3v-IUEkPmbMcAcutSIwP5lzOkVhsxiVXE_1774311795 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Rspamd-Queue-Id: 147B61C0005 X-Stat-Signature: 4655yuw7axr6s1owrfub91j7n9r8fzd4 X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1774311802-237896 X-HE-Meta: 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 YirRPSv+ fr3kMFrbsqLHA6Msr4dgddVZCrrw43ehFQMLSs/dayDpu5j38lRIPqMHm+Oploswbe4iwqfeLlDDtDVlYmEboV9cB/LyBoC9gKsaJawQr+o2nCLgjZGLgB23Zp0EuAuAwqWiijynNFtlS3Gry1Dy7JcmWf7Lpz/F/MI2i8nyJTSmF+PMlIYis/sf4NkCL+qGzung9VSZ5mBYeaBosQEKRrhIUMDkE3d37zb/In/8PSxco2SRDAclkJ951PK9KKcP4uTFQKtgAQY65z/zAjoNKYdqGjzBp+LPzY+J+vivoKDjYZhOQPZlZxBFlfsq4bqVFK69nGevuT7opPgapo8OWF4RO0R9FCaGhYtml4k22tUfUmFjxfMRKL83n5RjOJ59D2skDMBEBKlgQc86s1L0DSAXuWA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Mar 23, 2026 at 03:48:58PM +0000, Lorenzo Stoakes (Oracle) wrote: > On Mon, Mar 23, 2026 at 11:17:50PM +0800, Chunyu Hu wrote: > > thp_settings provides write_file() helper for safely writing to a file and > > exit when write failure happens. It's a very low level helper and many sub > > tests need such a helper, not only thp tests. > > > > split_huge_page_test also defines a write_file locally. The two have minior > > differences in return type and used exit api. And there would be conflicts > > if split_huge_page_test wanted to include thp_settings.h because of > > different prototype, making it less convenient. > > > > It's possisble to merge the two, although some tests don't use the > > kselftest infrastrucutre for testing. It would also work when using the > > ksft_exit_msg() to exit in my test, as the counters are all zero. Output > > will be like: > > > > TAP version 13 > > 1..62 > > Bail out! /proc/sys/vm/drop_caches1 open failed: No such file or directory > > # Totals: pass:0 fail:0 xfail:0 xpass:0 skip:0 error:0 > > > > So here we just keep the version in split_huge_page_test, and move it into > > the vm_util. This makes it easy to maitain and user could just include one > > vm_util.h when they don't need thp setting helpers. Keep the prototype of > > void return as the function will exit on any error, return value is not > > necessary, and will simply the callers like write_num() and write_string(). > > > > Acked-by: David Hildenbrand (Arm) > > Reviewed-by: Zi Yan > > Acked-by: Mike Rapoport (Microsoft) > > Suggested-by: Mike Rapoport > > Signed-off-by: Chunyu Hu > > I already reviewed this :) but easy to accidentally forget to propagate > tags. Anyway, as before: > > Reviewed-by: Lorenzo Stoakes (Oracle) Sorry I forgot adding your review in my last version. I'll add in v6. Thanks for your review! > > Cheers, Lorenzo > > > --- > > Changes in v5: > > - updated acked-by and reviewed-by > > Changes in v3: > > - make the write_file void return > > Changes in v2: > > new patch from v2 > > --- > > .../selftests/mm/split_huge_page_test.c | 15 -------- > > tools/testing/selftests/mm/thp_settings.c | 35 ++----------------- > > tools/testing/selftests/mm/thp_settings.h | 1 - > > tools/testing/selftests/mm/vm_util.c | 15 ++++++++ > > tools/testing/selftests/mm/vm_util.h | 2 ++ > > 5 files changed, 20 insertions(+), 48 deletions(-) > > > > diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c > > index e0167111bdd1..93f205327b84 100644 > > --- a/tools/testing/selftests/mm/split_huge_page_test.c > > +++ b/tools/testing/selftests/mm/split_huge_page_test.c > > @@ -255,21 +255,6 @@ static int check_after_split_folio_orders(char *vaddr_start, size_t len, > > return status; > > } > > > > -static void write_file(const char *path, const char *buf, size_t buflen) > > -{ > > - int fd; > > - ssize_t numwritten; > > - > > - fd = open(path, O_WRONLY); > > - if (fd == -1) > > - ksft_exit_fail_msg("%s open failed: %s\n", path, strerror(errno)); > > - > > - numwritten = write(fd, buf, buflen - 1); > > - close(fd); > > - if (numwritten < 1) > > - ksft_exit_fail_msg("Write failed\n"); > > -} > > - > > static void write_debugfs(const char *fmt, ...) > > { > > char input[INPUT_MAX]; > > diff --git a/tools/testing/selftests/mm/thp_settings.c b/tools/testing/selftests/mm/thp_settings.c > > index 574bd0f8ae48..e748ebfb3d4e 100644 > > --- a/tools/testing/selftests/mm/thp_settings.c > > +++ b/tools/testing/selftests/mm/thp_settings.c > > @@ -6,6 +6,7 @@ > > #include > > #include > > > > +#include "vm_util.h" > > #include "thp_settings.h" > > > > #define THP_SYSFS "/sys/kernel/mm/transparent_hugepage/" > > @@ -64,29 +65,6 @@ int read_file(const char *path, char *buf, size_t buflen) > > return (unsigned int) numread; > > } > > > > -int write_file(const char *path, const char *buf, size_t buflen) > > -{ > > - int fd; > > - ssize_t numwritten; > > - > > - fd = open(path, O_WRONLY); > > - if (fd == -1) { > > - printf("open(%s)\n", path); > > - exit(EXIT_FAILURE); > > - return 0; > > - } > > - > > - numwritten = write(fd, buf, buflen - 1); > > - close(fd); > > - if (numwritten < 1) { > > - printf("write(%s)\n", buf); > > - exit(EXIT_FAILURE); > > - return 0; > > - } > > - > > - return (unsigned int) numwritten; > > -} > > - > > unsigned long read_num(const char *path) > > { > > char buf[21]; > > @@ -104,10 +82,7 @@ void write_num(const char *path, unsigned long num) > > char buf[21]; > > > > sprintf(buf, "%ld", num); > > - if (!write_file(path, buf, strlen(buf) + 1)) { > > - perror(path); > > - exit(EXIT_FAILURE); > > - } > > + write_file(path, buf, strlen(buf) + 1); > > } > > > > int thp_read_string(const char *name, const char * const strings[]) > > @@ -165,11 +140,7 @@ void thp_write_string(const char *name, const char *val) > > printf("%s: Pathname is too long\n", __func__); > > exit(EXIT_FAILURE); > > } > > - > > - if (!write_file(path, val, strlen(val) + 1)) { > > - perror(path); > > - exit(EXIT_FAILURE); > > - } > > + write_file(path, val, strlen(val) + 1); > > } > > > > unsigned long thp_read_num(const char *name) > > diff --git a/tools/testing/selftests/mm/thp_settings.h b/tools/testing/selftests/mm/thp_settings.h > > index 76eeb712e5f1..7748a9009191 100644 > > --- a/tools/testing/selftests/mm/thp_settings.h > > +++ b/tools/testing/selftests/mm/thp_settings.h > > @@ -63,7 +63,6 @@ struct thp_settings { > > }; > > > > int read_file(const char *path, char *buf, size_t buflen); > > -int write_file(const char *path, const char *buf, size_t buflen); > > unsigned long read_num(const char *path); > > void write_num(const char *path, unsigned long num); > > > > diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c > > index a6d4ff7dfdc0..ad96d19d1b85 100644 > > --- a/tools/testing/selftests/mm/vm_util.c > > +++ b/tools/testing/selftests/mm/vm_util.c > > @@ -764,3 +764,18 @@ int unpoison_memory(unsigned long pfn) > > > > return ret > 0 ? 0 : -errno; > > } > > + > > +void write_file(const char *path, const char *buf, size_t buflen) > > +{ > > + int fd; > > + ssize_t numwritten; > > + > > + fd = open(path, O_WRONLY); > > + if (fd == -1) > > + ksft_exit_fail_msg("%s open failed: %s\n", path, strerror(errno)); > > + > > + numwritten = write(fd, buf, buflen - 1); > > + close(fd); > > + if (numwritten < 1) > > + ksft_exit_fail_msg("Write failed\n"); > > +} > > diff --git a/tools/testing/selftests/mm/vm_util.h b/tools/testing/selftests/mm/vm_util.h > > index e9c4e24769c1..1a07305ceff4 100644 > > --- a/tools/testing/selftests/mm/vm_util.h > > +++ b/tools/testing/selftests/mm/vm_util.h > > @@ -166,3 +166,5 @@ int unpoison_memory(unsigned long pfn); > > > > #define PAGEMAP_PRESENT(ent) (((ent) & (1ull << 63)) != 0) > > #define PAGEMAP_PFN(ent) ((ent) & ((1ull << 55) - 1)) > > + > > +void write_file(const char *path, const char *buf, size_t buflen); > > -- > > 2.53.0 > > >