Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751422AbdILOCK (ORCPT ); Tue, 12 Sep 2017 10:02:10 -0400 Received: from mail-wr0-f195.google.com ([209.85.128.195]:34341 "EHLO mail-wr0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751337AbdILOCH (ORCPT ); Tue, 12 Sep 2017 10:02:07 -0400 X-Google-Smtp-Source: ADKCNb6nEZ7ABHoeuoDiiFoNGO4070VSKQZwpU6FppeRP0PubSsjZ0aE8lpNfV0o4goC2OH+k5U5cIIcQa9HccoNZqM= MIME-Version: 1.0 In-Reply-To: <20170912094548.30603-1-colin.king@canonical.com> References: <20170912094548.30603-1-colin.king@canonical.com> From: Emil Velikov Date: Tue, 12 Sep 2017 15:02:04 +0100 Message-ID: Subject: Re: [PATCH] drm: qxl: ratelimit pr_info message, reduce log spamming To: Colin King Cc: Dave Airlie , Gerd Hoffmann , David Airlie , "open list:VIRTIO GPU DRIVER" , ML dri-devel , kernel-janitors@vger.kernel.org, "Linux-Kernel@Vger. Kernel. Org" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1696 Lines: 49 Hi Colin, On 12 September 2017 at 10:45, Colin King wrote: > From: Colin Ian King > > Simply mmap'ing /dev/dri/card0 repeatedly will spam the kernel > log with qxl_mmap information messages. The following example code > illustrates this: > > int main(void) > { > int fd = open("/dev/dri/card0", O_RDONLY); > if (fd == -1) > err(1, "open failed"); > > for (;;) { > void *m = mmap(NULL, 4096, PROT_READ, > MAP_SHARED, fd, 0); > if (m != MAP_FAILED) > munmap(m, 4096); > } > } > > Reduce the spamming by ratelimiting the pr_info messages. > > Signed-off-by: Colin Ian King > --- > drivers/gpu/drm/qxl/qxl_ttm.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/qxl/qxl_ttm.c b/drivers/gpu/drm/qxl/qxl_ttm.c > index 7ecf8a4b9fe6..6502e699f462 100644 > --- a/drivers/gpu/drm/qxl/qxl_ttm.c > +++ b/drivers/gpu/drm/qxl/qxl_ttm.c > @@ -124,7 +124,7 @@ int qxl_mmap(struct file *filp, struct vm_area_struct *vma) > int r; > > if (unlikely(vma->vm_pgoff < DRM_FILE_PAGE_OFFSET)) { > - pr_info("%s: vma->vm_pgoff (%ld) < DRM_FILE_PAGE_OFFSET\n", > + pr_info_ratelimited("%s: vma->vm_pgoff (%ld) < DRM_FILE_PAGE_OFFSET\n", Quick grep suggests that only qxl and vmwgfx produce any output in this case, likely for the reasons you mentioned. That said, I'm not sure how useful the information is - perhaps it's better to drop it all together? Regardless of the route taken, vmwgfx could use a similar fix. HTH Emil