From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm@linux-foundation.org Subject: [merged] elf-smaller-code-generation-around-auxv-vector-fill.patch removed from -mm tree Date: Fri, 31 Jan 2020 15:20:41 -0800 Message-ID: <20200131232041.3RURkE5FD%akpm@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from mail.kernel.org ([198.145.29.99]:52412 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726488AbgAaXUm (ORCPT ); Fri, 31 Jan 2020 18:20:42 -0500 Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: adobriyan@gmail.com, akpm@linux-foundation.org, mm-commits@vger.kernel.org The patch titled Subject: fs/binfmt_elf.c: smaller code generation around auxv vector fill has been removed from the -mm tree. Its filename was elf-smaller-code-generation-around-auxv-vector-fill.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Alexey Dobriyan Subject: fs/binfmt_elf.c: smaller code generation around auxv vector fill Filling auxv vector as array with index (auxv[i++] = ...) generates terrible code. "saved_auxv" should be reworked because it is the worst member of mm_struct by size/usefullness ratio but do it later. Meanwhile help gcc a little with *auxv++ idiom. Space savings on x86_64: add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-127 (-127) Function old new delta load_elf_binary 5470 5343 -127 Link: http://lkml.kernel.org/r/20191208172301.GD19716@avx2 Signed-off-by: Alexey Dobriyan Reviewed-by: Andrew Morton Signed-off-by: Andrew Morton --- fs/binfmt_elf.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) --- a/fs/binfmt_elf.c~elf-smaller-code-generation-around-auxv-vector-fill +++ a/fs/binfmt_elf.c @@ -176,7 +176,7 @@ create_elf_tables(struct linux_binprm *b unsigned char k_rand_bytes[16]; int items; elf_addr_t *elf_info; - int ei_index = 0; + int ei_index; const struct cred *cred = current_cred(); struct vm_area_struct *vma; @@ -230,8 +230,8 @@ create_elf_tables(struct linux_binprm *b /* update AT_VECTOR_SIZE_BASE if the number of NEW_AUX_ENT() changes */ #define NEW_AUX_ENT(id, val) \ do { \ - elf_info[ei_index++] = id; \ - elf_info[ei_index++] = val; \ + *elf_info++ = id; \ + *elf_info++ = val; \ } while (0) #ifdef ARCH_DLINFO @@ -275,12 +275,13 @@ create_elf_tables(struct linux_binprm *b } #undef NEW_AUX_ENT /* AT_NULL is zero; clear the rest too */ - memset(&elf_info[ei_index], 0, - sizeof current->mm->saved_auxv - ei_index * sizeof elf_info[0]); + memset(elf_info, 0, (char *)current->mm->saved_auxv + + sizeof(current->mm->saved_auxv) - (char *)elf_info); /* And advance past the AT_NULL entry. */ - ei_index += 2; + elf_info += 2; + ei_index = elf_info - (elf_addr_t *)current->mm->saved_auxv; sp = STACK_ADD(p, ei_index); items = (argc + 1) + (envc + 1) + 1; @@ -338,7 +339,7 @@ create_elf_tables(struct linux_binprm *b current->mm->env_end = p; /* Put the elf_info on the stack in the right place. */ - if (copy_to_user(sp, elf_info, ei_index * sizeof(elf_addr_t))) + if (copy_to_user(sp, current->mm->saved_auxv, ei_index * sizeof(elf_addr_t))) return -EFAULT; return 0; } _ Patches currently in -mm which might be from adobriyan@gmail.com are ramfs-support-o_tmpfile.patch proc-decouple-proc-from-vfs-with-struct-proc_ops.patch proc-convert-everything-to-struct-proc_ops.patch