From: Andrew Morton <akpm@linux-foundation.org>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Nick Piggin <npiggin@kernel.dk>,
"Xen-devel@lists.xensource.com" <Xen-devel@lists.xensource.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux Memory Management List <linux-mm@kvack.org>,
Trond Myklebust <Trond.Myklebust@netapp.com>,
Bryan Schumaker <bjschuma@netapp.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: [PATCH RFC] vmalloc: eagerly clear ptes on vunmap
Date: Tue, 30 Nov 2010 16:29:38 -0800 [thread overview]
Message-ID: <20101130162938.8a6b0df4.akpm@linux-foundation.org> (raw)
In-Reply-To: <4CF40DCB.5010007@goop.org>
On Mon, 29 Nov 2010 12:32:11 -0800
Jeremy Fitzhardinge <jeremy@goop.org> wrote:
> When unmapping a region in the vmalloc space, clear the ptes immediately.
> There's no point in deferring this because there's no amortization
> benefit.
>
> The TLBs are left dirty, and they are flushed lazily to amortize the
> cost of the IPIs.
>
> This specific motivation for this patch is a regression since 2.6.36 when
> using NFS under Xen, triggered by the NFS client's use of vm_map_ram()
> introduced in 56e4ebf877b6043c289bda32a5a7385b80c17dee. XFS also uses
> vm_map_ram() and could cause similar problems.
>
Do we have any quantitative info on that regression? The patch fixed
it, I assume?
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Nick Piggin <npiggin@kernel.dk>,
"Xen-devel@lists.xensource.com" <Xen-devel@lists.xensource.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux Memory Management List <linux-mm@kvack.org>,
Trond Myklebust <Trond.Myklebust@netapp.com>,
Bryan Schumaker <bjschuma@netapp.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: [PATCH RFC] vmalloc: eagerly clear ptes on vunmap
Date: Tue, 30 Nov 2010 16:29:38 -0800 [thread overview]
Message-ID: <20101130162938.8a6b0df4.akpm@linux-foundation.org> (raw)
In-Reply-To: <4CF40DCB.5010007@goop.org>
On Mon, 29 Nov 2010 12:32:11 -0800
Jeremy Fitzhardinge <jeremy@goop.org> wrote:
> When unmapping a region in the vmalloc space, clear the ptes immediately.
> There's no point in deferring this because there's no amortization
> benefit.
>
> The TLBs are left dirty, and they are flushed lazily to amortize the
> cost of the IPIs.
>
> This specific motivation for this patch is a regression since 2.6.36 when
> using NFS under Xen, triggered by the NFS client's use of vm_map_ram()
> introduced in 56e4ebf877b6043c289bda32a5a7385b80c17dee. XFS also uses
> vm_map_ram() and could cause similar problems.
>
Do we have any quantitative info on that regression? The patch fixed
it, I assume?
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next prev parent reply other threads:[~2010-12-01 0:30 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-26 8:10 Could we do immediate pte zaps in vunmap? Jeremy Fitzhardinge
2010-11-27 10:36 ` Nick Piggin
2010-11-29 20:32 ` [PATCH RFC] vmalloc: eagerly clear ptes on vunmap Jeremy Fitzhardinge
2010-11-29 20:32 ` Jeremy Fitzhardinge
2010-11-30 12:42 ` Nick Piggin
2010-11-30 12:42 ` Nick Piggin
2010-11-30 17:45 ` Jeremy Fitzhardinge
2010-11-30 17:45 ` Jeremy Fitzhardinge
2010-12-01 0:29 ` Andrew Morton [this message]
2010-12-01 0:29 ` Andrew Morton
2010-12-01 3:09 ` Jeremy Fitzhardinge
2010-12-01 3:09 ` Jeremy Fitzhardinge
2010-12-01 3:23 ` Andrew Morton
2010-12-01 3:23 ` Andrew Morton
2010-12-01 8:16 ` Jeremy Fitzhardinge
2010-12-01 8:16 ` Jeremy Fitzhardinge
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