From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760681AbcCEK56 (ORCPT ); Sat, 5 Mar 2016 05:57:58 -0500 Received: from mail-pa0-f52.google.com ([209.85.220.52]:35159 "EHLO mail-pa0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754305AbcCEK5u (ORCPT ); Sat, 5 Mar 2016 05:57:50 -0500 From: Sergey Senozhatsky To: Andrew Morton Cc: Jan Kara , Petr Mladek , Tejun Heo , Tetsuo Handa , linux-kernel@vger.kernel.org, Sergey Senozhatsky , Sergey Senozhatsky Subject: [RFC][PATCH v2 0/2] printk: Make printk() completely async Date: Sat, 5 Mar 2016 19:55:36 +0900 Message-Id: <1457175338-1665-1-git-send-email-sergey.senozhatsky@gmail.com> X-Mailer: git-send-email 2.8.0.rc0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, RFC The patch set is a slightly updated Jan Kara's patches. The majority of the changes are in 0001 (described below in details). I've performed some tests and haven't spotted any problems, I'll certainly do more tests. Any feedback is appreciated. I had additional patches on top of the series, but I decided not to post them. I'm unhappy with console semaphore, this must be a separate mail loop and a patch set, some day. The patch set is against next-20160304 with reverted NMI patches. v2 (Sergey): - use dedicated printk workqueue with WQ_MEM_RECLAIM bit - fallback to system-wide workqueue only if allocation of printk_wq has failed - do not use system_wq as a fallback wq. both console_lock() and onsole_unlock() can spend a significant amount of time; so we need to use system_long_wq. - rework sync/!sync detection logic a) we can have deferred (in_sched) messages before we allocate printk_wq, so the only way to handle those messages is via IRQ context b) even in printk.synchronous mode, deferred messages must not be printed directly, and should go via IRQ context c) even if we allocated printk_wq and have !sync_printk mode, we must route deferred messages via IRQ context - so this adds additional bool flags to vprint_emit() and introduces a new pending bit to `printk_pending' - fix build on !PRINTK configs Jan Kara (2): printk: Make printk() completely async printk: Skip messages on oops Documentation/kernel-parameters.txt | 10 ++ kernel/printk/printk.c | 230 +++++++++++++++++++++++++++--------- 2 files changed, 181 insertions(+), 59 deletions(-) -- 2.8.0.rc0