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Date:   Thu, 12 Dec 2019 12:22:40 +0100
From:   Joerg Roedel <jroedel@suse.de>
To:     Chen-Yu Tsai <wens@kernel.org>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable <stable@vger.kernel.org>, Pavel Machek <pavel@denx.de>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Andrew Morton <akpm@linux-foundation.org>
Subject: Re: Regression from "mm/vmalloc: Sync unmappings in
 __purge_vmap_area_lazy()" in stable kernels
Message-ID: <20191212112240.GI4477@suse.de>
References: <CAGb2v656iHP+6X12gT+Kfc3BkM2w=rU6yfHTk03JgaXrUy02TA@mail.gmail.com>
 <20191212111911.GH4477@suse.de>
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On Thu, Dec 12, 2019 at 12:19:11PM +0100, Joerg Roedel wrote:
> Hi,
> 
> On Thu, Dec 12, 2019 at 06:54:12PM +0800, Chen-Yu Tsai wrote:
> > I'd like to report a very severe performance regression due to
> > 
> >     mm/vmalloc: Sync unmappings in __purge_vmap_area_lazy() in stable kernels
> 
> Yes, that is a known problem, with a couple of reports already in the
> past months. And I posted a fix from which I thought it is on its way
> upstream, but apparently its not:
> 
> 	https://lore.kernel.org/lkml/20191009124418.8286-1-joro@8bytes.org/

Ah, I missed that it is in linux-next already. Sorry for the noise.


	Joerg