From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DE709C19437 for ; Wed, 9 Dec 2020 03:07:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AE31B23B19 for ; Wed, 9 Dec 2020 03:07:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727091AbgLIDHc (ORCPT ); Tue, 8 Dec 2020 22:07:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44466 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726995AbgLIDHb (ORCPT ); Tue, 8 Dec 2020 22:07:31 -0500 Received: from mail-ej1-x641.google.com (mail-ej1-x641.google.com [IPv6:2a00:1450:4864:20::641]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6487BC0613D6 for ; Tue, 8 Dec 2020 19:06:51 -0800 (PST) Received: by mail-ej1-x641.google.com with SMTP id a16so924530ejj.5 for ; Tue, 08 Dec 2020 19:06:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=intel-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=8AFvZy5IevjnVMOU6zN7P4dA9MmKNHlLYmheYvMwvVc=; b=VCeHrc0dr9kgX339cC7qkulsq0krr/xcafwkxj1skiTLZ6/3KXgaUsnTDhDv4Tnhwz MTS8SLN1O0oZAoepsdeB5niM7vOMGclnYbLg9sIHQDhc/Z5E9Oz5USTaQzvSxCz6oxtW TxmBwIvvaem6z/nwACcCJnqe02TxeDkx2+P0gAsRt8sIpX9edLRRaki/7I5qwbL1CR/Z EemZFdefbA8N00+QQYJtiOXUUQ4iLl9sBXVMPjH6AFnmiyle86yLpJIFZdUM/egh3QCj 0BW9bvVSzrWebrFu3thuq0w6cl6NXl5G1vMA3VQ5zVihU//GhRT2z6nslyexycsxaslL dVmw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=8AFvZy5IevjnVMOU6zN7P4dA9MmKNHlLYmheYvMwvVc=; b=bmqD2nyq5RzSVzuV8fuhA0f4zQrdbKLiYaJipS3N+6lwqQzglKnljeircQrUbtpz3I EfpXcEg3IhnUnBWCbCk7CJ1ZE36RZzFum+uDZ4BMPdyn2K/t6gO0sYwtGmdqv1EjspDG M1XWKrOAZVzmXhwQRfI31UXm8ZdvjoFlDyqVflPgyJKPPF7/nhmT+il2h+j1o/RHKuhf G+BkIloYVrmCurY3uUhMd9Bn8vU78fvqNvr17nyhIBigNA76V6r1p79NovFnUXhI5ITB 7SoMAS/bLvLw31t6B8W67qRHOvkkxI4NI1noJQyixmOevbkIkHYHngVXa4jGvieMoYak o8+Q== X-Gm-Message-State: AOAM530tl93S6XeKBY1frSC1R1W+2Ivhj0kFgePeUSwSXrbyfNu0qNw/ NyjgURLohvQ9EArKv5gj/MrBanmW2rH5VQUE+KQF8g== X-Google-Smtp-Source: ABdhPJzUtnkqj+yNOhhOCy3e+1NMY2uMlUDSW/4qX+FAGO719KojfcgyijbDv+uhsfz5/UdMq0VYUDVav22eZQBYxMw= X-Received: by 2002:a17:906:edb2:: with SMTP id sa18mr327438ejb.264.1607483209942; Tue, 08 Dec 2020 19:06:49 -0800 (PST) MIME-Version: 1.0 References: <20201209002418.1976362-1-ben.widawsky@intel.com> <20201209002418.1976362-13-ben.widawsky@intel.com> <20201209020433.bzsuqudbgtpbtggk@intel.com> In-Reply-To: <20201209020433.bzsuqudbgtpbtggk@intel.com> From: Dan Williams Date: Tue, 8 Dec 2020 19:06:46 -0800 Message-ID: Subject: Re: [RFC PATCH 12/14] cxl: Add basic debugging To: Ben Widawsky Cc: linux-cxl@vger.kernel.org, Linux Kernel Mailing List , Linux PCI , Linux ACPI , Ira Weiny , Vishal Verma , "Kelley, Sean V" , Rafael Wysocki , Bjorn Helgaas , Jonathan Cameron , Jon Masters , Chris Browy , Randy Dunlap , Christoph Hellwig Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 8, 2020 at 6:04 PM Ben Widawsky wrote: > > On 20-12-08 17:17:36, Dan Williams wrote: > > On Tue, Dec 8, 2020 at 4:24 PM Ben Widawsky wrote: > > > > > > Provide a standard debug function for use throughout the driver. > > > > > > Signed-off-by: Ben Widawsky > > > --- > > > drivers/cxl/cxl.h | 3 +++ > > > drivers/cxl/mem.c | 26 +++++++++++++++++++++++++- > > > 2 files changed, 28 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h > > > index 77c2dee6843c..e5afb89dab0b 100644 > > > --- a/drivers/cxl/cxl.h > > > +++ b/drivers/cxl/cxl.h > > > @@ -9,6 +9,9 @@ > > > #include > > > #include > > > > > > +#define cxl_debug(fmt, ...) \ > > > + pr_debug("CXL DEBUG: %s: " fmt, __func__, ##__VA_ARGS__) > > > + > > > > This should be dev_dbg(), then you don't need the CXL DEBUG prefix. In > > fact you don't need a cxl_debug() macro at all in that case. cxl_mem > > might need a ->dev attribute for this purpose. > > > > I really like the ability to turn specific messages on and off at will. (FWIW, > __func__ is also redundant because pr_debug allows you to specify a flag to > always print the function name). While it's not very frequent events here, in > the future it likely will be and I think it can be really helpful to be able to > have that level of control. > > If you want to avoid creating a new debug functionality, I'm okay with that, but > I'd really like to use pr_debug instead of dev_dbg for those messages going > forward. Once you take that step, it seems giving contributors a macro named > 'cxl_debug' so they don't have to figure out when to use what, makes sense. My > mental separation is, dev_* is useful primarily for errors and initialization > debug messaging, pr_debug/trace_printk is for runtime things. > > I probably should have put that in the commit message... I suspect you haven't taken a look at the backed and of pr_debug() and dev_dbg() in a while? They both use _dynamic_func_call and enjoy all the benefits afforded by /sys/debug/dynamic_debug/control and the "dyndbg" module option for adding __func__ and enable / disable by line number or format message . pr_debug() and this cxl_debug() macro are completely superseded by dev_dbg(). Even if a driver wanted a common prefix on all prints there is the "#define dev_fmt ..." mechanism for that. > > > > #define CXL_SET_FIELD(value, field) \ > > > ({ \ > > > WARN_ON(!FIELD_FIT(field##_MASK, value)); \ > > > diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c > > > index a2cea7ac7cc6..6b2f8d3776b5 100644 > > > --- a/drivers/cxl/mem.c > > > +++ b/drivers/cxl/mem.c > > > @@ -122,9 +122,12 @@ static int cxl_mem_wait_for_doorbell(struct cxl_mem *cxlm) > > > { > > > const int timeout = msecs_to_jiffies(2000); > > > const unsigned long start = jiffies; > > > + unsigned long end = start; > > > > > > while (cxl_doorbell_busy(cxlm)) { > > > - if (time_after(jiffies, start + timeout)) { > > > + end = jiffies; > > > + > > > + if (time_after(end, start + timeout)) { > > > /* Check again in case preempted before timeout test */ > > > if (!cxl_doorbell_busy(cxlm)) > > > break; > > > @@ -133,6 +136,8 @@ static int cxl_mem_wait_for_doorbell(struct cxl_mem *cxlm) > > > cpu_relax(); > > > } > > > > > > + cxl_debug("Doorbell wait took %dms", > > > + jiffies_to_msecs(end) - jiffies_to_msecs(start)); > > > return 0; > > > } > > > > > > @@ -180,6 +185,8 @@ static int cxl_mem_mbox_send_cmd(struct cxl_mem *cxlm, > > > } > > > > > > /* #4 */ > > > + cxl_debug("Sending command to %s\n", > > > + dev_driver_string(&cxlm->pdev->dev)); > > > > dev_dbg() already includes dev_driver_string(). > > > > > cxl_write_mbox_reg32(cxlm, CXLDEV_MB_CTRL_OFFSET, > > > CXLDEV_MB_CTRL_DOORBELL); > > > > > > @@ -308,6 +315,8 @@ static int cxl_mem_open(struct inode *inode, struct file *file) > > > if (!cxlmd) > > > return -ENXIO; > > > > > > + cxl_debug("Opened %pD\n", file); > > > + > > > file->private_data = cxlmd; > > > > > > return 0; > > > @@ -383,6 +392,10 @@ static int handle_mailbox_cmd_from_user(struct cxl_memdev *cxlmd, > > > .size_in = cmd->info.size_in, > > > .size_out = size_out, > > > }; > > > + cxl_debug("Submitting command for user\n" > > > + "\topcode: %x\n" > > > + "\tsize: %zub/%zub\n", > > > + mbox_cmd.opcode, mbox_cmd.size_in, mbox_cmd.size_out); > > > rc = cxl_mem_mbox_send_cmd(cxlmd->cxlm, &mbox_cmd); > > > cxl_mem_mbox_put(cxlmd->cxlm); > > > if (rc) > > > @@ -479,6 +492,8 @@ static long cxl_mem_ioctl(struct file *file, unsigned int cmd, unsigned long arg > > > u32 n_commands; > > > int i, j; > > > > > > + cxl_debug("Query IOCTL\n"); > > > + > > > if (get_user(n_commands, (u32 __user *)arg)) > > > return -EFAULT; > > > > > > @@ -511,6 +526,8 @@ static long cxl_mem_ioctl(struct file *file, unsigned int cmd, unsigned long arg > > > struct cxl_mem_command c; > > > int rc; > > > > > > + cxl_debug("Send IOCTL\n"); > > > + > > > rc = cxl_validate_cmd_from_user(u, &c); > > > if (rc) > > > return rc; > > > @@ -843,6 +860,13 @@ static int cxl_mem_identify(struct cxl_mem *cxlm) > > > > > > id = (struct cxl_mbox_identify *)mbox_cmd.payload; > > > > > > + cxl_debug("Driver identify command\n" > > > + "\tFirmware Version: %s\n" > > > + "\tTotal Capacity: %llu (%llu persistent)\n" > > > + "\tLSA size: %u\n", > > > + id->fw_revision, id->total_capacity, id->persistent_capacity, > > > + id->lsa_size); > > > + > > > > Seems not necessary for details that are published in sysfs? > > I was thinking for cases where driver doesn't bind, seeing the identify > information could be useful. This is one case where dev_dbg would also serve > IMO. There's very little that can cause bind failures after cxl_mem_identify() succeeds. The bind failures themselves will dev_err() the reason.