From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.223.130]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AB27B15AAB6; Fri, 31 May 2024 14:06:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.135.223.130 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717164411; cv=none; b=dIXYLepo9stGdY9sdQXQnIu+sIkK5cpUKBU/qOnHzHCM0bGodNcaLfMzLuZalKgBTt6KIdV9G3q3B4OmZaZSkLxCPCFJ6Mk9EthSHJZnK6NaPL22vPAQ3ib4MAE+xS6/IAKddToAvzCotfQ+ethtmkvmld8HSwCn79gmP0Wkgrg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717164411; c=relaxed/simple; bh=B0DkizkCx/fHuPXQz+PWG9GhSLvk9fuZqO3xRqWCRa8=; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References: MIME-Version:Content-Type; b=iYMJvXFQcmyv9VzrqX0c18HQhpYj0bP1ydFwnXHs+OuB9fX1q+XHGqXIl50wMzDxkmn+cskeaJYcu/63oAlGU7fLsSjjRczsKo/1Be51FhCheZB7k+9Qz44/AgTspx/3CYsnfwok0nM2MioME6So+mljC5MUomj6gg+l+jur/xw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz; spf=pass smtp.mailfrom=suse.cz; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b=HWU0AKd8; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b=WLnUVKXA; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b=HWU0AKd8; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b=WLnUVKXA; arc=none smtp.client-ip=195.135.223.130 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.cz Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b="HWU0AKd8"; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b="WLnUVKXA"; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b="HWU0AKd8"; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b="WLnUVKXA" Received: from pobox.suse.cz (unknown [10.100.2.14]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id A64D321C2E; Fri, 31 May 2024 14:06:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1717164407; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=AO8BLC7Qkg5rQsHrBBnOGJ6JR70Q2hPHi932MvWcJaM=; b=HWU0AKd8EnvtjSBqVusMGY5bRvpXFwYCGiqcypc5wCkZzslVnIGgUPbTJQfNQrPz9vQvbm Vl5RdOsXSTW0v8ZY0VkMl4/YyoiOjxF4QLuAhbidSUO8C9a7wylQPBDVz1vwJfPkqwHi8R g9D5GnEAFCpXv9XJlHc8/Z7RFYV4TB0= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1717164407; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=AO8BLC7Qkg5rQsHrBBnOGJ6JR70Q2hPHi932MvWcJaM=; b=WLnUVKXAunT4ia+0z6CfgQly3KOe6hh13QG+CbJDByQBsjnLV8u4wLNPChnpU0NsIvkpj6 wq2p0srj1d4272AA== Authentication-Results: smtp-out1.suse.de; none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1717164407; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=AO8BLC7Qkg5rQsHrBBnOGJ6JR70Q2hPHi932MvWcJaM=; b=HWU0AKd8EnvtjSBqVusMGY5bRvpXFwYCGiqcypc5wCkZzslVnIGgUPbTJQfNQrPz9vQvbm Vl5RdOsXSTW0v8ZY0VkMl4/YyoiOjxF4QLuAhbidSUO8C9a7wylQPBDVz1vwJfPkqwHi8R g9D5GnEAFCpXv9XJlHc8/Z7RFYV4TB0= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1717164407; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=AO8BLC7Qkg5rQsHrBBnOGJ6JR70Q2hPHi932MvWcJaM=; b=WLnUVKXAunT4ia+0z6CfgQly3KOe6hh13QG+CbJDByQBsjnLV8u4wLNPChnpU0NsIvkpj6 wq2p0srj1d4272AA== Date: Fri, 31 May 2024 16:06:46 +0200 (CEST) From: Miroslav Benes To: zhang warden cc: Petr Mladek , Josh Poimboeuf , Jiri Kosina , Joe Lawrence , live-patching@vger.kernel.org, LKML Subject: Re: [PATCH] livepatch: introduce klp_func called interface In-Reply-To: Message-ID: References: <20240520005826.17281-1-zhangwarden@gmail.com> <2551BBD9-735E-4D1E-B1AE-F5A3F0C38815@gmail.com> User-Agent: Alpine 2.21 (LSU 202 2017-01-01) Precedence: bulk X-Mailing-List: live-patching@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="1678380546-857398901-1717164406=:8344" X-Spam-Flag: NO X-Spam-Score: -2.69 X-Spam-Level: X-Spamd-Result: default: False [-2.69 / 50.00]; BAYES_HAM(-3.00)[99.99%]; CTYPE_MIXED_BOGUS(1.00)[]; NEURAL_HAM_LONG(-0.39)[-0.394]; NEURAL_HAM_SHORT(-0.20)[-0.999]; MIME_GOOD(-0.10)[multipart/mixed,text/plain]; TO_MATCH_ENVRCPT_ALL(0.00)[]; ARC_NA(0.00)[]; RCVD_COUNT_ZERO(0.00)[0]; FROM_HAS_DN(0.00)[]; MIME_TRACE(0.00)[0:+,1:+]; FROM_EQ_ENVFROM(0.00)[]; FREEMAIL_TO(0.00)[gmail.com]; MID_RHS_MATCH_FROMTLD(0.00)[]; FUZZY_BLOCKED(0.00)[rspamd.com]; RCPT_COUNT_SEVEN(0.00)[7]; DKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; TO_DN_SOME(0.00)[]; FREEMAIL_ENVRCPT(0.00)[gmail.com] This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --1678380546-857398901-1717164406=:8344 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT > And for the unlikely branch, isn’t the complier will compile this branch > into a cold branch that will do no harm to the function performance? The test (cmp insn or something like that) still needs to be there. Since there is only a simple assignment in the branch, the compiler may just choose not to have a cold branch in this case. The only difference is in which case you would jump here. You can see for yourself (and prove me wrong if it comes to it). Miroslav --1678380546-857398901-1717164406=:8344--