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Sat, 26 Sep 2026 08:24:17 -0700 (PDT) From: Danish Khateeb To: Willy Tarreau , =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= Cc: Shuah Khan , linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Danish Khateeb Subject: [PATCH v2 1/2] tools/nolibc: stop rounding malloc() sizes up to 4096 bytes Date: Sat, 26 Sep 2026 10:24:13 -0500 Message-ID: <20260926152414.251214-2-danishkhateeb03@gmail.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260926152414.251214-1-danishkhateeb03@gmail.com> References: <20260926152414.251214-1-danishkhateeb03@gmail.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit malloc() rounds the size of each mapping up to a multiple of 4096, presumably to align it to a page boundary. But the page size is not 4096 on all architectures, and mmap() and munmap() round the length up to the page size themselves. Drop the rounding. As heap->len is no longer rounded up, growing a block with realloc() now always creates a new mapping. Assisted-by: LLM Signed-off-by: Danish Khateeb --- tools/include/nolibc/stdlib.h | 2 -- 1 file changed, 2 deletions(-) diff --git a/tools/include/nolibc/stdlib.h b/tools/include/nolibc/stdlib.h index 6c3c620a04cf..dc554faff22a 100644 --- a/tools/include/nolibc/stdlib.h +++ b/tools/include/nolibc/stdlib.h @@ -130,9 +130,7 @@ void *malloc(size_t len) { struct nolibc_heap *heap; - /* Always allocate memory with size multiple of 4096. */ len = sizeof(*heap) + len; - len = (len + 4095UL) & -4096UL; heap = mmap(NULL, len, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0); if (__builtin_expect(heap == MAP_FAILED, 0)) -- 2.55.0