From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.223.131]) (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 ADFA2315D2B for ; Thu, 15 Jan 2026 08:48:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.135.223.131 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768466938; cv=none; b=NGN+CtwJBDPVDVLFSKg4TnlaMSWjEa9Xcgn+K96kc6y5MhkPTtObH59p/poUI+VNY3vkNN+OuVzYCT5Jv7ws1h9glaRULEIUZyJScUBbfb7R/vMDa8GwFjZl3DDTw7NrRX6vzSsX0ZFAzXxdTPmNabz9q3vw2D+RkCwK2+1Zrbs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768466938; c=relaxed/simple; bh=FxwDNa3KSC2/Vu/T2oGTKgNI3YzjmFWxBDANh7dfFng=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=hmwL7ESeKv+EjfHCk6k15yhPzSLLBWq7ZCvoPMXYfJZqvYgqWGccRwrDX1V/ZuDjQCuoMY4TWBD8hXJ4Nx2BSRheBB8bqiuatzPFsdVZoUEVAp2OlblLLbDEHUker1MjpaOGcbAJ4UaBrzpeiPmfUqrgz9VksbRmqBBysYGvauQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com; spf=pass smtp.mailfrom=suse.com; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b=oY/oDF+N; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b=oY/oDF+N; arc=none smtp.client-ip=195.135.223.131 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="oY/oDF+N"; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="oY/oDF+N" Received: from imap1.dmz-prg2.suse.org (imap1.dmz-prg2.suse.org [IPv6:2a07:de40:b281:104:10:150:64:97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 012EB5BCEB; Thu, 15 Jan 2026 08:48:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1768466934; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=T4gQhUuagqLQmvTbN6c66jJbuGTJE17NFmXSnIA/TI8=; b=oY/oDF+NuXX3VQAMqj48JB2uJpwCE02l/tyX1XP8NP8s8NDMfNclL60SpFFymmyPD8xbKm 3zQFJ7U6Dsz2aQ7TBXM+KT0K5gugtITLCIqJaODaSpR2C3X3UjJBR5+hk/YzNFViJrRj7q gg7DeJg2TV0yKBcuSezRh2RRr5lGf+4= Authentication-Results: smtp-out2.suse.de; dkim=pass header.d=suse.com header.s=susede1 header.b="oY/oDF+N" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1768466934; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=T4gQhUuagqLQmvTbN6c66jJbuGTJE17NFmXSnIA/TI8=; b=oY/oDF+NuXX3VQAMqj48JB2uJpwCE02l/tyX1XP8NP8s8NDMfNclL60SpFFymmyPD8xbKm 3zQFJ7U6Dsz2aQ7TBXM+KT0K5gugtITLCIqJaODaSpR2C3X3UjJBR5+hk/YzNFViJrRj7q gg7DeJg2TV0yKBcuSezRh2RRr5lGf+4= Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id B147A3EA63; Thu, 15 Jan 2026 08:48:52 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id PESNKPSpaGnEIAAAD6G6ig (envelope-from ); Thu, 15 Jan 2026 08:48:52 +0000 From: Juergen Gross To: linux-kernel@vger.kernel.org, x86@kernel.org, virtualization@lists.linux.dev, kvm@vger.kernel.org, linux-block@vger.kernel.org Cc: Juergen Gross , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Ajay Kaher , Alexey Makhalov , Broadcom internal kernel review list , Paolo Bonzini , Vitaly Kuznetsov , Boris Ostrovsky , xen-devel@lists.xenproject.org, Denis Efremov , Jens Axboe Subject: [PATCH v3 0/5] x86: Cleanups around slow_down_io() Date: Thu, 15 Jan 2026 09:48:44 +0100 Message-ID: <20260115084849.31502-1-jgross@suse.com> X-Mailer: git-send-email 2.51.0 Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Score: -3.01 X-Spamd-Result: default: False [-3.01 / 50.00]; BAYES_HAM(-3.00)[100.00%]; MID_CONTAINS_FROM(1.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_MISSING_CHARSET(0.50)[]; R_DKIM_ALLOW(-0.20)[suse.com:s=susede1]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; SPAMHAUS_XBL(0.00)[2a07:de40:b281:104:10:150:64:97:from]; FUZZY_RATELIMITED(0.00)[rspamd.com]; DKIM_SIGNED(0.00)[suse.com:s=susede1]; MIME_TRACE(0.00)[0:+]; RBL_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:104:10:150:64:97:from]; RCPT_COUNT_TWELVE(0.00)[20]; ARC_NA(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; FROM_HAS_DN(0.00)[]; RECEIVED_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:106:10:150:64:167:received]; DNSWL_BLOCKED(0.00)[2a07:de40:b281:106:10:150:64:167:received,2a07:de40:b281:104:10:150:64:97:from]; FROM_EQ_ENVFROM(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCVD_TLS_ALL(0.00)[]; DKIM_TRACE(0.00)[suse.com:+]; TO_DN_SOME(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.com:dkim,suse.com:mid,imap1.dmz-prg2.suse.org:rdns,imap1.dmz-prg2.suse.org:helo] X-Spam-Level: X-Rspamd-Action: no action X-Rspamd-Queue-Id: 012EB5BCEB X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Spam-Flag: NO While looking at paravirt cleanups I stumbled over slow_down_io() and the related REALLY_SLOW_IO define. Do several cleanups, resulting in a deletion of REALLY_SLOW_IO and the io_delay() paravirt function hook. Patch 4 is removing the config options for selecting the default delay mechanism and sets the default to "no delay". This is in preparation of removing the io_delay() functionality completely, as suggested by Ingo Molnar. Patch 5 is adding an additional config option allowing to avoid building io_delay.c (default is still to build it). Changes in V2: - patches 2 and 3 of V1 have been applied - new patches 4 and 5 Changes in V3: - rebase to tip/master kernel branch Juergen Gross (5): x86/paravirt: Replace io_delay() hook with a bool block/floppy: Don't use REALLY_SLOW_IO for delays x86/io: Remove REALLY_SLOW_IO handling x86/io_delay: Switch io_delay() default mechanism to "none" x86/io_delay: Add config option for controlling build of io_delay. arch/x86/Kconfig | 8 +++ arch/x86/Kconfig.debug | 30 ---------- arch/x86/include/asm/floppy.h | 31 ++++++++-- arch/x86/include/asm/io.h | 19 ++++--- arch/x86/include/asm/paravirt-base.h | 6 ++ arch/x86/include/asm/paravirt.h | 11 ---- arch/x86/include/asm/paravirt_types.h | 2 - arch/x86/kernel/Makefile | 3 +- arch/x86/kernel/cpu/vmware.c | 2 +- arch/x86/kernel/io_delay.c | 81 +-------------------------- arch/x86/kernel/kvm.c | 8 +-- arch/x86/kernel/paravirt.c | 3 +- arch/x86/kernel/setup.c | 4 +- arch/x86/xen/enlighten_pv.c | 6 +- drivers/block/floppy.c | 2 - 15 files changed, 60 insertions(+), 156 deletions(-) -- 2.51.0