From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 D859045C6F0 for ; Thu, 3 Sep 2026 08:56:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788425809; cv=none; b=LanoDQoy0Y+IrHq2sn7BenOGWICE1n7jYc4QbcrcJo5cb5DTD4UgvIBwRGGw9/uADkRstp/ay1ibCNKDxJzH+1C3kKzfvTbTH/AVHYp1wC01m+L34xrkAVmKCsM3HS8PSdwZJJYmQRXbnnq3st1boslQsr6EstgFa+AsZArtqOw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788425809; c=relaxed/simple; bh=JFRIKGgs0b/YpbOzAkoVkjWaYNPYinE0bDaDudjWH7I=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=V0pMfZ9n8KGwkPwUmHPTg7dXIvuOuDxip2Itt6r53iUGCMXlzTVc/JfSrUG5dfPWymevP6TMLvHIaW8YQOcz+xYR2ucFK9DPUDidNaS50MnEl/nG/JWI977yiZkjGHr4FMxYE5chZsfnAMvDh+wNjLcJGfiufxAJm9VzkEkDx3c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gZJm0Nlp; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="gZJm0Nlp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AB67B1F000E9; Thu, 3 Sep 2026 08:56:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788425807; bh=02Mp9uiZ68zR1+hJOqkaY67SDX1dZpFZicQbRabXLyE=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=gZJm0NlpxGy1opG5c/XRYPPveJhKB2Lg52PUFQl0Ch1+jBlY0kPOwgZsUafGfx64b omQplvqURVBceUvkV8g8uNXBazVtt0w7uRdGxFWWTp5AaYdRatk7IlC2evYL7g9n2e 1KRzwR9D6Nj9/SNLplHbhioGVjF0jWqAiQNsJd8t6EHvW2SsU4JMu/TtPqnefecaJM yINtjvlgEC0GT3DzZvhMqoVopcj1hnktZhePnlUSdCI+MVfdr4at/JP6onOz4Gzpbs CS62PkOczfZJko7S1UbGi87Dulpor0EEg886CfVkCoXNQzgVuS/YdJfV4SyxKLfp9v zpvT3DR6abX/Q== Date: Thu, 3 Sep 2026 09:56:40 +0100 From: "Lorenzo Stoakes (ARM)" To: Yeoreum Yun Cc: linux-mm@kvack.org, linux-kselftest@vger.kernel.org, akpm@linux-foundation.org, david@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, shuah@kernel.org, ziy@nvidia.com, baolin.wang@linux.alibaba.com, nico.pache@linux.dev, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, usama.arif@linux.dev, kas@kernel.org Subject: Re: [PATCH] kselftest: mm: remove HPAGE_SIZE and HPAGE_SHIFT macro Message-ID: References: <20260902175611.1241118-1-yeoreum.yun@arm.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260902175611.1241118-1-yeoreum.yun@arm.com> On Wed, Sep 02, 2026 at 06:56:11PM +0100, Yeoreum Yun wrote: > HPAGE_SIZE and HPAGE_SHIFT macro is written based on the 4KB PAGE_SIZE. > When this macro is used in some test, test result would be strange in > the system where PAGE_SIZE is more than 4KB. > > Here is example with transhuge-stress test with 16KB PAGE_SIZE: > > transhuge-stress: allocate 61073 transhuge pages, using 122146 MiB virtual memory and 1908 MiB of ram > 3.292 s/loop, 0.054 ms/page, 37106.002 MiB/s 2566 succeed, 58507 failed, 2566 different pages > 0.591 s/loop, 0.010 ms/page, 206850.792 MiB/s 0 succeed, 61073 failed, 0 different pages > 0.527 s/loop, 0.009 ms/page, 231895.107 MiB/s 0 succeed, 61073 failed, 0 different pages > 0.527 s/loop, 0.009 ms/page, 231839.704 MiB/s 0 succeed, 61073 failed, 0 different pages > 0.528 s/loop, 0.009 ms/page, 231544.782 MiB/s 0 succeed, 61073 failed, 0 different pages > 0.528 s/loop, 0.009 ms/page, 231462.074 MiB/s 0 succeed, 61073 failed, 0 different pages > 0.527 s/loop, 0.009 ms/page, 231770.300 MiB/s 0 succeed, 61073 failed, 0 different pages > ... > ok 1 Completed > > Remove the HPAGE_SIZE and HPAGE_SHIFT macro. and introduce hpshift() > helper to get the HPAGE_SHIFT properly. For HPAGE_SIZE, use pre-exist > helper, read_pmd_pagesize(). > > Also, do KSM_MERGE_TIME_HUGE_PAGES test with size of 512 MiB which > is the LCD pmd_size among 4KB, 16KB and 64KB page_size. Probably worth spelling out Least Common Denominator for those who might mistaken this for a kind of display panel :P I also wonder if it's worth pulling that out as a separate patch in a series for better bisectability? > > After this patch, output of transhuge-stress: > > transhuge-stress: allocate 3817 transhuge pages, using 122146 MiB virtual memory and 119 MiB of ram > 2.558 s/loop, 0.670 ms/page, 47755.759 MiB/s 2585 succeed, 1232 failed, 2585 different pages > 2.640 s/loop, 0.692 ms/page, 46268.432 MiB/s 2585 succeed, 1232 failed, 2585 different pages > 2.635 s/loop, 0.690 ms/page, 46360.298 MiB/s 2585 succeed, 1232 failed, 2585 different pages > 2.782 s/loop, 0.729 ms/page, 43899.795 MiB/s 2616 succeed, 1201 failed, 2616 different pages > 2.692 s/loop, 0.705 ms/page, 45380.876 MiB/s 2627 succeed, 1190 failed, 2627 different pages > 2.612 s/loop, 0.684 ms/page, 46765.812 MiB/s 2628 succeed, 1189 failed, 2628 different pages > 2.683 s/loop, 0.703 ms/page, 45520.990 MiB/s 2630 succeed, 1187 failed, 2630 different pages > 2.727 s/loop, 0.714 ms/page, 44789.321 MiB/s 2631 succeed, 1186 failed, 2631 different pages > ... > ok 1 Completed > > Suggested-by: Lorenzo Stoakes (ARM) > Signed-off-by: Yeoreum Yun Firstly THANK YOU for doing this :) hugely appreciated. Also thank you again for the birthday cakes ;) And apologies for the nitpicks :P > --- > tools/testing/selftests/mm/guard-regions.c | 12 +++++-- > tools/testing/selftests/mm/ksm_tests.c | 17 ++++++---- > tools/testing/selftests/mm/run_vmtests.sh | 4 +-- > tools/testing/selftests/mm/transhuge-stress.c | 22 +++++++------ > tools/testing/selftests/mm/vm_util.c | 32 ++++++++++++++++--- > tools/testing/selftests/mm/vm_util.h | 9 ++---- > 6 files changed, 66 insertions(+), 30 deletions(-) > > diff --git a/tools/testing/selftests/mm/guard-regions.c b/tools/testing/selftests/mm/guard-regions.c > index 5c8ec3ca75d7..d370592b291f 100644 > --- a/tools/testing/selftests/mm/guard-regions.c > +++ b/tools/testing/selftests/mm/guard-regions.c > @@ -2195,14 +2195,22 @@ TEST_F(guard_regions, pagemap_scan) > TEST_F(guard_regions, collapse) > { > const unsigned long page_size = self->page_size; > - const unsigned long size = 2 * HPAGE_SIZE; > - const unsigned long num_pages = size / page_size; > + uint64_t hpage_size; > + unsigned long size; > + unsigned long num_pages; > char *ptr; > int i; > > if (!thp_available()) > SKIP(return, "Transparent Hugepages not available\n"); > > + hpage_size = read_pmd_pagesize(); > + if (!hpage_size) > + ksft_exit_fail_msg("reading hpage_size failed\n"); > + > + size = 2 * hpage_size; > + num_pages = size / page_size; > + > /* Need file to be correct size for tests for non-anon. */ > if (variant->backing != ANON_BACKED) > ASSERT_EQ(ftruncate(self->fd, size), 0); > diff --git a/tools/testing/selftests/mm/ksm_tests.c b/tools/testing/selftests/mm/ksm_tests.c > index 5fd7792a0d47..278e77055007 100644 > --- a/tools/testing/selftests/mm/ksm_tests.c > +++ b/tools/testing/selftests/mm/ksm_tests.c > @@ -521,6 +521,11 @@ static int ksm_merge_hugepages_time(int merge_type, int mapping, int prot, > struct timespec start_time, end_time; > unsigned long scan_time_ns; > int pagemap_fd, n_normal_pages, n_huge_pages; > + uint64_t hpage_size = read_pmd_pagesize(); NIT: can this be const? > + > + if (!hpage_size) { > + ksft_exit_fail_msg("reading hpage_size failed\n"); > + } NIT: can drop the {} > > if (!thp_is_enabled()) { > ksft_print_msg("Transparent Hugepages not available\n"); > @@ -530,10 +535,10 @@ static int ksm_merge_hugepages_time(int merge_type, int mapping, int prot, > map_size *= MB; > size_t len = map_size; > > - len -= len % HPAGE_SIZE; > - map_ptr_orig = mmap(NULL, len + HPAGE_SIZE, PROT_READ | PROT_WRITE, > + len -= len % hpage_size; > + map_ptr_orig = mmap(NULL, len + hpage_size, PROT_READ | PROT_WRITE, > MAP_ANONYMOUS | MAP_NORESERVE | MAP_PRIVATE, -1, 0); > - map_ptr = map_ptr_orig + HPAGE_SIZE - (uintptr_t)map_ptr_orig % HPAGE_SIZE; > + map_ptr = map_ptr_orig + hpage_size - (uintptr_t)map_ptr_orig % hpage_size; > > if (map_ptr_orig == MAP_FAILED) > err(2, "initial mmap"); > @@ -547,7 +552,7 @@ static int ksm_merge_hugepages_time(int merge_type, int mapping, int prot, > > n_normal_pages = 0; > n_huge_pages = 0; > - for (void *p = map_ptr; p < map_ptr + len; p += HPAGE_SIZE) { > + for (void *p = map_ptr; p < map_ptr + len; p += hpage_size) { > if (allocate_transhuge(p, pagemap_fd) < 0) > n_normal_pages++; > else > @@ -578,11 +583,11 @@ static int ksm_merge_hugepages_time(int merge_type, int mapping, int prot, > ksft_print_msg("Average speed: %.3f MiB/s\n", (map_size / MB) / > ((double)scan_time_ns / NSEC_PER_SEC)); > > - munmap(map_ptr_orig, len + HPAGE_SIZE); > + munmap(map_ptr_orig, len + hpage_size); > return KSFT_PASS; > > err_out: > - munmap(map_ptr_orig, len + HPAGE_SIZE); > + munmap(map_ptr_orig, len + hpage_size); > return KSFT_FAIL; > } > > diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh > index d09f9f6a384e..24aa1de27c25 100755 > --- a/tools/testing/selftests/mm/run_vmtests.sh > +++ b/tools/testing/selftests/mm/run_vmtests.sh > @@ -360,8 +360,8 @@ fi > CATEGORY="memfd_secret" run_test ./memfd_secret > fi > > -# KSM KSM_MERGE_TIME_HUGE_PAGES test with size of 100 > -CATEGORY="ksm" run_test ./ksm_tests -H -s 100 > +# KSM KSM_MERGE_TIME_HUGE_PAGES test with size of 512 > +CATEGORY="ksm" run_test ./ksm_tests -H -s 512 See above re: splitting out. > # KSM KSM_MERGE_TIME test with size of 100 > CATEGORY="ksm" run_test ./ksm_tests -P -s 100 > # KSM MADV_MERGEABLE test with 10 identical pages > diff --git a/tools/testing/selftests/mm/transhuge-stress.c b/tools/testing/selftests/mm/transhuge-stress.c > index 8eb0c5630e7e..66ae94afaf8d 100644 > --- a/tools/testing/selftests/mm/transhuge-stress.c > +++ b/tools/testing/selftests/mm/transhuge-stress.c > @@ -35,6 +35,8 @@ int main(int argc, char **argv) > size_t map_len; > int pagemap_fd; > int duration = 0; > + uint64_t hpage_size = read_pmd_pagesize(); > + uint64_t hpage_shift = hpshift(); NIT: could be consts? > > ksft_print_header(); > > @@ -70,23 +72,23 @@ int main(int argc, char **argv) > } > > warnx("allocate %zd transhuge pages, using %zd MiB virtual memory" > - " and %zd MiB of ram", len >> HPAGE_SHIFT, len >> 20, > - ram >> (20 + HPAGE_SHIFT - pshift() - 1)); > + " and %zd MiB of ram", len >> hpage_shift, len >> 20, > + ram >> (20 + hpage_shift - pshift() - 1)); > > pagemap_fd = open("/proc/self/pagemap", O_RDONLY); > if (pagemap_fd < 0) > ksft_exit_fail_msg("open pagemap\n"); > > - len -= len % HPAGE_SIZE; > - ptr = mmap(NULL, len + HPAGE_SIZE, PROT_RW, mmap_flags, backing_fd, 0); > + len -= len % hpage_size; > + ptr = mmap(NULL, len + hpage_size, PROT_RW, mmap_flags, backing_fd, 0); > if (ptr == MAP_FAILED) > ksft_exit_fail_msg("initial mmap"); > - ptr += HPAGE_SIZE - (uintptr_t)ptr % HPAGE_SIZE; > + ptr += hpage_size - (uintptr_t)ptr % hpage_size; > > if (madvise(ptr, len, MADV_HUGEPAGE)) > ksft_exit_fail_msg("MADV_HUGEPAGE"); > > - map_len = ram >> (HPAGE_SHIFT - 1); > + map_len = ram >> (hpage_shift - 1); > map = malloc(map_len); > if (!map) > ksft_exit_fail_msg("map malloc\n"); > @@ -99,7 +101,7 @@ int main(int argc, char **argv) > memset(map, 0, map_len); > > clock_gettime(CLOCK_MONOTONIC, &a); > - for (p = ptr; p < ptr + len; p += HPAGE_SIZE) { > + for (p = ptr; p < ptr + len; p += hpage_size) { > int64_t pfn; > > pfn = allocate_transhuge(p, pagemap_fd); > @@ -107,7 +109,7 @@ int main(int argc, char **argv) > if (pfn < 0) { > nr_failed++; > } else { > - size_t idx = pfn >> (HPAGE_SHIFT - pshift()); > + size_t idx = pfn >> (hpage_shift - pshift()); > > nr_succeed++; > if (idx >= map_len) { > @@ -123,7 +125,7 @@ int main(int argc, char **argv) > } > > /* split transhuge page, keep last page */ > - if (madvise(p, HPAGE_SIZE - psize(), MADV_DONTNEED)) > + if (madvise(p, hpage_size - psize(), MADV_DONTNEED)) > ksft_exit_fail_msg("MADV_DONTNEED"); > } > clock_gettime(CLOCK_MONOTONIC, &b); > @@ -131,7 +133,7 @@ int main(int argc, char **argv) > > ksft_print_msg("%.3f s/loop, %.3f ms/page, %10.3f MiB/s\t" > "%4d succeed, %4d failed, %4d different pages\n", > - s, s * 1000 / (len >> HPAGE_SHIFT), len / s / (1 << 20), > + s, s * 1000 / (len >> hpage_shift), len / s / (1 << 20), > nr_succeed, nr_failed, nr_pages); > > if (duration > 0 && b.tv_sec - start.tv_sec >= duration) { > diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c > index 4821a3563036..4332f8fb2104 100644 > --- a/tools/testing/selftests/mm/vm_util.c > +++ b/tools/testing/selftests/mm/vm_util.c > @@ -21,6 +21,8 @@ > > unsigned int __page_size; > unsigned int __page_shift; > +uint64_t __hpage_size; > +uint64_t __hpage_shift; > > uint64_t pagemap_get_entry(int fd, char *start) > { > @@ -161,6 +163,9 @@ uint64_t read_pmd_pagesize(void) > char buf[20]; > ssize_t num_read; > > + if (__hpage_size) > + return __hpage_size; > + > fd = open(PMD_SIZE_FILE_PATH, O_RDONLY); > if (fd == -1) > return 0; > @@ -173,7 +178,24 @@ uint64_t read_pmd_pagesize(void) > buf[num_read] = '\0'; > close(fd); > > - return strtoul(buf, NULL, 10); > + __hpage_size = strtoul(buf, NULL, 10); > + > + return __hpage_size; > +} > + > +uint64_t hpshift(void) > +{ > + if (!__hpage_shift) { > + if (!__hpage_size) { > + __hpage_size = read_pmd_pagesize(); > + if (!__hpage_size) > + ksft_exit_fail_msg("reading __hpage_size failed\n"); > + } This nesting is a bit horrifying :P Maybe: if (__hpage_shift && __hpage_size) return; if (!__hpage_size) { ... } if (!__hpage_shift) { ... } ? > + > + __hpage_shift = (ffsl(__hpage_size) - 1); > + } > + > + return __hpage_shift; > } > > unsigned long rss_anon(void) > @@ -452,14 +474,16 @@ bool check_huge_shmem(void *addr, size_t len, int nr_hpages, uint64_t hpage_size > int64_t allocate_transhuge(void *ptr, int pagemap_fd) > { > uint64_t ent[2]; > + uint64_t hpage_size = read_pmd_pagesize(); > + uint64_t hpage_shift = hpshift(); NIT: could be const? > > /* drop pmd */ > - if (mmap(ptr, HPAGE_SIZE, PROT_READ | PROT_WRITE, > + if (mmap(ptr, hpage_size, PROT_READ | PROT_WRITE, > MAP_FIXED | MAP_ANONYMOUS | > MAP_NORESERVE | MAP_PRIVATE, -1, 0) != ptr) > ksft_exit_fail_msg("mmap transhuge\n"); > > - if (madvise(ptr, HPAGE_SIZE, MADV_HUGEPAGE)) > + if (madvise(ptr, hpage_size, MADV_HUGEPAGE)) > ksft_exit_fail_msg("MADV_HUGEPAGE\n"); > > /* allocate transparent huge page */ > @@ -471,7 +495,7 @@ int64_t allocate_transhuge(void *ptr, int pagemap_fd) > > if (PAGEMAP_PRESENT(ent[0]) && PAGEMAP_PRESENT(ent[1]) && > PAGEMAP_PFN(ent[0]) + 1 == PAGEMAP_PFN(ent[1]) && > - !(PAGEMAP_PFN(ent[0]) & ((1 << (HPAGE_SHIFT - pshift())) - 1))) > + !(PAGEMAP_PFN(ent[0]) & ((1 << (hpage_shift - pshift())) - 1))) > return PAGEMAP_PFN(ent[0]); > > return -1; > diff --git a/tools/testing/selftests/mm/vm_util.h b/tools/testing/selftests/mm/vm_util.h > index 9a49af88702e..20a6334605c7 100644 > --- a/tools/testing/selftests/mm/vm_util.h > +++ b/tools/testing/selftests/mm/vm_util.h > @@ -31,6 +31,8 @@ > > extern unsigned int __page_size; > extern unsigned int __page_shift; > +extern uint64_t __hpage_size; > +extern uint64_t __hpage_shift; > > /* > * Represents an open fd and PROCMAP_QUERY state for binary (via ioctl) > @@ -89,6 +91,7 @@ unsigned long pagemap_get_pfn(int fd, char *start); > void clear_softdirty(void); > bool check_for_pattern(FILE *fp, const char *pattern, char *buf, size_t len); > uint64_t read_pmd_pagesize(void); > +uint64_t hpshift(void); > unsigned long rss_anon(void); > bool check_huge_anon(void *addr, size_t len, int nr_hpages, uint64_t hpage_size); > bool check_huge_file(void *addr, size_t len, int nr_hpages, uint64_t hpage_size); > @@ -157,12 +160,6 @@ int ksm_stop(void); > int get_hardware_corrupted_size(unsigned long *val); > int unpoison_memory(unsigned long pfn); > > -/* > - * On ppc64 this will only work with radix 2M hugepage size > - */ > -#define HPAGE_SHIFT 21 > -#define HPAGE_SIZE (1 << HPAGE_SHIFT) > - Worth calling this change out in commit msg also? > #define PAGEMAP_PRESENT(ent) (((ent) & (1ull << 63)) != 0) > #define PAGEMAP_PFN(ent) ((ent) & ((1ull << 55) - 1)) > > -- > LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7} > -- Cheers, Lorenzo