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Date:   Mon, 6 Sep 2021 18:13:20 -0400
From:   Bruce Fields <bfields@fieldses.org>
To:     Matthew Wilcox <willy@infradead.org>
Cc:     Chuck Lever III <chuck.lever@oracle.com>,
        Neil Brown <neilb@suse.de>,
        Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
        Mel Gorman <mgorman@suse.com>, Linux-MM <linux-mm@kvack.org>
Subject: Re: [PATCH] SUNRPC: use congestion_wait() in svc_alloc_args()
Message-ID: <20210906221320.GA21567@fieldses.org>
References: <163090344807.19339.10071205771966144716@noble.neil.brown.name>
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 <YTZ4E0Zh6F/WSpy0@casper.infradead.org>
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On Mon, Sep 06, 2021 at 09:20:35PM +0100, Matthew Wilcox wrote:
> On Mon, Sep 06, 2021 at 03:46:34PM +0000, Chuck Lever III wrote:
> > Hi Neil-
> > 
> > > On Sep 6, 2021, at 12:44 AM, NeilBrown <neilb@suse.de> wrote:
> > > 
> > > 
> > > Many places that need to wait before retrying a memory allocation use
> > > congestion_wait().  xfs_buf_alloc_pages() is a good example which
> > > follows a similar pattern to that in svc_alloc_args().
> > > 
> > > It make sense to do the same thing in svc_alloc_args(); This will allow
> > > the allocation to be retried sooner if some backing device becomes
> > > non-congested before the timeout.
> 
> It's adorable that you believe this is still true.
> 
> https://lore.kernel.org/linux-mm/20191231125908.GD6788@bombadil.infradead.org/

So, what's the advice for now?  Do we add the congestion_wait() call
anyway and assume it'll be fixed to do something less broken in the
future, or just skip it completely?

--b.