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Wed, 8 Feb 2023 18:23:50 +0100 (CET) Message-ID: <20230208172245.501847188@infradead.org> User-Agent: quilt/0.66 Date: Wed, 08 Feb 2023 18:18:00 +0100 From: Peter Zijlstra To: x86@kernel.org, jpoimboe@redhat.com, linux@weissschuh.net Cc: linux-kernel@vger.kernel.org, peterz@infradead.org Subject: [PATCH 04/10] objtool: Shrink instruction::{type,visited} References: <20230208171756.898991570@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Since we don't have that many types in enum insn_type, force it into a u8 and re-arrange member to get rid of the holes, saves another 8 bytes. struct instruction { struct list_head list; /* 0 16 */ struct hlist_node hash; /* 16 16 */ struct list_head call_node; /* 32 16 */ struct section * sec; /* 48 8 */ long unsigned int offset; /* 56 8 */ /* --- cacheline 1 boundary (64 bytes) --- */ - unsigned int len; /* 64 4 */ - enum insn_type type; /* 68 4 */ - long unsigned int immediate; /* 72 8 */ - u16 dead_end:1; /* 80: 0 2 */ - u16 ignore:1; /* 80: 1 2 */ - u16 ignore_alts:1; /* 80: 2 2 */ - u16 hint:1; /* 80: 3 2 */ - u16 save:1; /* 80: 4 2 */ - u16 restore:1; /* 80: 5 2 */ - u16 retpoline_safe:1; /* 80: 6 2 */ - u16 noendbr:1; /* 80: 7 2 */ - u16 entry:1; /* 80: 8 2 */ + long unsigned int immediate; /* 64 8 */ + unsigned int len; /* 72 4 */ + u8 type; /* 76 1 */ - /* XXX 7 bits hole, try to pack */ + /* Bitfield combined with previous fields */ - s8 instr; /* 82 1 */ - u8 visited; /* 83 1 */ + u16 dead_end:1; /* 76: 8 2 */ + u16 ignore:1; /* 76: 9 2 */ + u16 ignore_alts:1; /* 76:10 2 */ + u16 hint:1; /* 76:11 2 */ + u16 save:1; /* 76:12 2 */ + u16 restore:1; /* 76:13 2 */ + u16 retpoline_safe:1; /* 76:14 2 */ + u16 noendbr:1; /* 76:15 2 */ + u16 entry:1; /* 78: 0 2 */ + u16 visited:4; /* 78: 1 2 */ - /* XXX 4 bytes hole, try to pack */ + /* XXX 3 bits hole, try to pack */ + /* Bitfield combined with next fields */ - struct alt_group * alt_group; /* 88 8 */ - struct symbol * call_dest; /* 96 8 */ - struct instruction * jump_dest; /* 104 8 */ - struct instruction * first_jump_src; /* 112 8 */ - struct reloc * jump_table; /* 120 8 */ + s8 instr; /* 79 1 */ + struct alt_group * alt_group; /* 80 8 */ + struct symbol * call_dest; /* 88 8 */ + struct instruction * jump_dest; /* 96 8 */ + struct instruction * first_jump_src; /* 104 8 */ + struct reloc * jump_table; /* 112 8 */ + struct reloc * reloc; /* 120 8 */ /* --- cacheline 2 boundary (128 bytes) --- */ - struct reloc * reloc; /* 128 8 */ - struct alternative * alts; /* 136 8 */ - struct symbol * sym; /* 144 8 */ - struct stack_op * stack_ops; /* 152 8 */ - struct cfi_state * cfi; /* 160 8 */ + struct alternative * alts; /* 128 8 */ + struct symbol * sym; /* 136 8 */ + struct stack_op * stack_ops; /* 144 8 */ + struct cfi_state * cfi; /* 152 8 */ - /* size: 168, cachelines: 3, members: 29 */ - /* sum members: 162, holes: 1, sum holes: 4 */ - /* sum bitfield members: 9 bits, bit holes: 1, sum bit holes: 7 bits */ - /* last cacheline: 40 bytes */ + /* size: 160, cachelines: 3, members: 29 */ + /* sum members: 158 */ + /* sum bitfield members: 13 bits, bit holes: 1, sum bit holes: 3 bits */ + /* last cacheline: 32 bytes */ }; pre: 5:48.86 real, 220.30 user, 128.34 sys, 24834672 mem post: 5:48.89 real, 220.96 user, 127.55 sys, 24834672 mem Signed-off-by: Peter Zijlstra (Intel) --- tools/objtool/include/objtool/check.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) --- a/tools/objtool/include/objtool/check.h +++ b/tools/objtool/include/objtool/check.h @@ -42,9 +42,9 @@ struct instruction { struct list_head call_node; struct section *sec; unsigned long offset; - unsigned int len; - enum insn_type type; unsigned long immediate; + unsigned int len; + u8 type; =20 u16 dead_end : 1, ignore : 1, @@ -54,11 +54,11 @@ struct instruction { restore : 1, retpoline_safe : 1, noendbr : 1, - entry : 1; - /* 7 bit hole */ + entry : 1, + visited : 4; + /* 3 bit hole */ =20 s8 instr; - u8 visited; =20 struct alt_group *alt_group; struct symbol *call_dest;