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Date: Wed, 28 Dec 2011 09:14:02 +0900 From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com> To: Tejun Heo <tj@...nel.org> Cc: Vivek Goyal <vgoyal@...hat.com>, Andrew Morton <akpm@...ux-foundation.org>, avi@...hat.com, nate@...nel.net, cl@...ux-foundation.org, oleg@...hat.com, axboe@...nel.dk, linux-kernel@...r.kernel.org Subject: Re: [PATCHSET] block, mempool, percpu: implement percpu mempool and fix blkcg percpu alloc deadlock On Tue, 27 Dec 2011 09:52:49 -0800 Tejun Heo <tj@...nel.org> wrote: > Hello, KAMEZAWA. > > On Mon, Dec 26, 2011 at 03:05:31PM +0900, KAMEZAWA Hiroyuki wrote: > > From 433b56fd5644d4b1e695bc16bbf8dd78842999fd Mon Sep 17 00:00:00 2001 > > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com> > > Date: Mon, 26 Dec 2011 15:06:21 +0900 > > Subject: [PATCH] percpu_counter: add lazy init > > > > percpu_counter calls alloc_percpu(). This means percpu_counter_init() > > assumes GFP_KERNEL context. This may call vmalloc() in percpu_counter > > allocation and will have locks. > > > > If a caller doesn't want to assume GFP_KERNEL, we need some tricks. > > This patch adds percpu_counter_init_lazy(). > > > > At lazy allocation, the function leaves fbc->counters as NULL and > > init fbc->counters by workqueue. This work item handling is done > > by fbc->list, so, the struct size of 'fbc' will not increase if > > a user configs CONFIG_HOTPLUG_CPU. > > This is essentially more specialized form of the mempool approach. It > doesn't seem any simpler to me while being less generic. I don't see > what the upside would be. > Hm, but this never causes -ENOMEM error, at all. Thanks, -Kame -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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