From nobody Fri Nov 7 13:02:04 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (208.118.235.17 [208.118.235.17]) by mx.zohomail.com with SMTPS id 1539041423161585.6454920463517; Mon, 8 Oct 2018 16:30:23 -0700 (PDT) Received: from localhost ([::1]:48741 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1g9eya-0001oE-Nk for importer@patchew.org; Mon, 08 Oct 2018 19:30:12 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33902) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1g9ewV-0000ft-Ob for qemu-devel@nongnu.org; Mon, 08 Oct 2018 19:28:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1g9ewS-0000Uq-BB for qemu-devel@nongnu.org; Mon, 08 Oct 2018 19:28:03 -0400 Received: from out3-smtp.messagingengine.com ([66.111.4.27]:56037) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1g9ewS-0000UA-00 for qemu-devel@nongnu.org; Mon, 08 Oct 2018 19:28:00 -0400 Received: from compute4.internal (compute4.nyi.internal [10.202.2.44]) by mailout.nyi.internal (Postfix) with ESMTP id AD64E21E33; Mon, 8 Oct 2018 19:27:59 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute4.internal (MEProxy); Mon, 08 Oct 2018 19:27:59 -0400 Received: from localhost (flamenco.cs.columbia.edu [128.59.20.216]) by mail.messagingengine.com (Postfix) with ESMTPA id 5B3F6102E7; Mon, 8 Oct 2018 19:27:59 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=braap.org; h= from:to:cc:subject:date:message-id:in-reply-to:references; s= mesmtp; bh=vHJaixzGPHj+t06w4wgC2cK3GbDqV5RRsRsLJtKmK5s=; b=oZfCN fOYJxFH75jYguyXkWerJdLAMKcMrzJpiolk748gKZlqlSm5eAl8bzg8Hut8Q3B+a ASgpAfqsyJXciDcVkU0dlRCciezgz02ODGMCQEud1Lp0QY7hwh/Q+I/e07u0WhkO 5FugbKsv6XoZgzjR8gDxdEq9OuuINS02+UHC38= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:date:from:in-reply-to:message-id :references:subject:to:x-me-proxy:x-me-proxy:x-me-sender :x-me-sender:x-sasl-enc; s=fm3; bh=vHJaixzGPHj+t06w4wgC2cK3GbDqV 5RRsRsLJtKmK5s=; b=fJjjFcwTWeJXNQMq1YoJIka31X7mNHtkYtRrFT3VHHj02 HiQWPhdn6mCHNjzGl+kxCl4NeTEx8eXDwxB6KuRQELB5mhwZHJbmi6bGLo+l0RNe qyxfndpKQrIByQTkIsIT321hQTHjHkXyd3v4kYM1r1qzPP+swFxhb01mpbAV8uqI XvlDF/62os/GgLyePbbc4FBjhhicHJYYUW59K6y600E3MUn0t2Q7JQaS+A5W8Umx pZQKDu3o0WCbXBRcoJYsOHB/JcTcO8LuqDUfHG/N7Zb8duvWRN3IESxIU0wTRR5+ 5aJpJ8NG18F4vRCkrUI+BSgZZtdm5NuaVfoLjM9Jw== X-ME-Sender: X-ME-Proxy: From: "Emilio G. Cota" To: qemu-devel@nongnu.org Date: Mon, 8 Oct 2018 19:27:54 -0400 Message-Id: <20181008232756.30704-4-cota@braap.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181008232756.30704-1-cota@braap.org> References: <20181008232756.30704-1-cota@braap.org> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 66.111.4.27 Subject: [Qemu-devel] [RFC v2 3/5] cputlb: do not evict empty entries to the vtlb X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: =?UTF-8?q?Alex=20Benn=C3=A9e?= , Richard Henderson Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Currently we evict an entry to the victim TLB when it doesn't match the current address. But it could be that there's no match because the current entry is empty (i.e. all -1's, for instance via tlb_flush). Do not evict the entry to the vtlb in that case. This change will help us keep track of the TLB's use rate. Signed-off-by: Emilio G. Cota Reviewed-by: Alex Benn=C3=A9e Reviewed-by: Richard Henderson --- include/exec/cpu-all.h | 9 +++++++++ accel/tcg/cputlb.c | 2 +- 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h index 117d2fbbca..e21140049b 100644 --- a/include/exec/cpu-all.h +++ b/include/exec/cpu-all.h @@ -362,6 +362,15 @@ static inline bool tlb_hit(target_ulong tlb_addr, targ= et_ulong addr) return tlb_hit_page(tlb_addr, addr & TARGET_PAGE_MASK); } =20 +/** + * tlb_entry_is_empty - return true if the entry is not in use + * @te: pointer to CPUTLBEntry + */ +static inline bool tlb_entry_is_empty(const CPUTLBEntry *te) +{ + return te->addr_read =3D=3D -1 && te->addr_write =3D=3D -1 && te->addr= _code =3D=3D -1; +} + void dump_exec_info(FILE *f, fprintf_function cpu_fprintf); void dump_opcount_info(FILE *f, fprintf_function cpu_fprintf); #endif /* !CONFIG_USER_ONLY */ diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c index 80406f1033..4dc47e603c 100644 --- a/accel/tcg/cputlb.c +++ b/accel/tcg/cputlb.c @@ -689,7 +689,7 @@ void tlb_set_page_with_attrs(CPUState *cpu, target_ulon= g vaddr, * Only evict the old entry to the victim tlb if it's for a * different page; otherwise just overwrite the stale data. */ - if (!tlb_hit_page_anyprot(te, vaddr_page)) { + if (!tlb_hit_page_anyprot(te, vaddr_page) && !tlb_entry_is_empty(te)) { unsigned vidx =3D env->vtlb_index++ % CPU_VTLB_SIZE; CPUTLBEntry *tv =3D &env->tlb_v_table[mmu_idx][vidx]; =20 --=20 2.17.1