From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: ARC-Seal: i=1; a=rsa-sha256; t=1525100169; cv=none; d=google.com; s=arc-20160816; b=xviiPM8uBWobANQ9oJ3QkyS+bRik/+J7BW5sQjuBw0cUGb8yiykV/bu2miq3rse4LO kT8Bxl/Jw7j99o3YcJ/5TLYgsdC+PnRySL7CX62rJdMp389zvGG+r1xxUEzUNgWKxpXh 6EEigmzi0GU+mzK9KXl5GxKEvnCM8dwQJyce69UcgDpRbCz4C7trVzxfdBHQhGuz+pDN f36mlMIAL1y7uOcgvyteRVakhLBBKV8+nWGtjOMoTsMeoqDH838Gwib1BDBgN7/Rc7BS UCfgSB2P55Jp99gHuBAbNpOj2l6rxxmN/yEtQ9moJrFrFrLJJR10/EYiaQfH/SLiXiY6 2pYw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=message-id:date:subject:cc:to:from:dkim-signature :arc-authentication-results; bh=ocO7Yk13OYCSN4eCYPhuRJ29wJp1e1v9UBvMeP671W0=; b=ujgUXgI8IJYzNHCYkr5EbQ7ZLnHbLLRYxgO2sdVtQ1z1+07u7b7Xd1seA2+q7RAxjg A/hul1r0vrWnvGiDN/g4yLCsnu+4I9k8SBTBTIsqyjyAHCNV/h+XGtZMFJgeUGG8b/sY sUcADmQwLgIWI5OaJ2w+/wtmiqwV3ZCmDhSGLmdw6BncAEu6988MM80aXuG3NYcHZglh CIMxd/ze3JK3YiOwGCnIVsCE2R5eqrjQ1VDW94relWnVnYmirhZSTC0vhUhRGtR+jcuN FJVtfHxhrCS1K8ukJ+RlTtrxMzQgzR+XTwqkSRyabW3FTx+VomuD5en50WJYY4tv8Iu7 RnZw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=pVbNruL2; spf=pass (google.com: domain of npiggin@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=npiggin@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=pVbNruL2; spf=pass (google.com: domain of npiggin@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=npiggin@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com X-Google-Smtp-Source: AB8JxZo8vTcdS6Tp63Pj4hO1eWjYJpKFnRp+r9Vnc9tDnaSu5+pxfUIz6Akw2t6/xzjE1qzKtIcuvw== From: Nicholas Piggin To: linuxppc-dev@lists.ozlabs.org Cc: Nicholas Piggin , Benjamin Herrenschmidt , Greg Kroah-Hartman , Jiri Slaby , linux-kernel@vger.kernel.org Subject: [PATCH 00/15] hvc and powerpc opal console latency reduction Date: Tue, 1 May 2018 00:55:43 +1000 Message-Id: <20180430145558.4308-1-npiggin@gmail.com> X-Mailer: git-send-email 2.17.0 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1599183434800910372?= X-GMAIL-MSGID: =?utf-8?q?1599183434800910372?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: I'm seeing scattered reports of hard lockups triggering in the OPAL console code. I haven't got a full latency trace -- they are difficult to reproduce and sometimes just show up in dmesg of a bug report when the system is having other issues. But it does seem like there are some improvements that can be made to the hvc console and powerpc opal driver. I'm not sure how this series should be merged yet, but we can cross that if/when it comes. Possibly all can go via the tty tree with acks from powerpc maintainers. Comments appreciated. Thanks, Nick -- Nicholas Piggin (15): powerpc/powernv: opal_put_chars partial write fix powerpc/powernv: Fix OPAL console driver OPAL_BUSY loops powerpc/powernv: opal-kmsg standardise OPAL_BUSY handling powerpc/powernv: opal-kmsg use flush fallback from console code powerpc/powernv: Implement and use opal_flush_console powerpc/powernv: Remove OPALv1 support from opal console driver powerpc/powernv: move opal console flushing to udbg powerpc/powernv: implement opal_put_chars_atomic tty: hvc: remove unexplained "just in case" spin delay tty: hvc: use mutex instead of spinlock for hvc_structs lock tty: hvc: hvc_poll break hv read loop tty: hvc: hvc_poll may sleep tty: hvc: hvc_write may sleep tty: hvc: introduce the hv_ops.flush operation for hvc drivers powerpc/powernv: provide a console flush operation for opal hvc driver arch/powerpc/include/asm/opal.h | 3 + arch/powerpc/platforms/powernv/opal-kmsg.c | 30 +--- arch/powerpc/platforms/powernv/opal.c | 176 +++++++++++++------ drivers/tty/hvc/hvc_console.c | 194 +++++++++++++-------- drivers/tty/hvc/hvc_console.h | 1 + drivers/tty/hvc/hvc_opal.c | 33 ++-- 6 files changed, 276 insertions(+), 161 deletions(-) -- 2.17.0