From: Andrew Morton <akpm@linux-foundation.org>
To: Nick Piggin <npiggin@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Ingo Molnar <mingo@redhat.com>,
x86@kernel.org, Hugh Dickins <hughd@google.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Rik van Riel <riel@redhat.com>, Mel Gorman <mgorman@suse.de>,
kosaki.motohiro@jp.fujitsu.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [RFC] propagate gfp_t to page table alloc functions
Date: Tue, 24 Apr 2012 14:30:15 -0700 [thread overview]
Message-ID: <20120424143015.99fd8d4a.akpm@linux-foundation.org> (raw)
In-Reply-To: <CAPa8GCCwfCFO6yxwUP5Qp9O1HGUqEU2BZrrf50w8TL9FH9vbrA@mail.gmail.com>
On Tue, 24 Apr 2012 17:48:29 +1000
Nick Piggin <npiggin@gmail.com> wrote:
> > Hmm, there are several places to use GFP_NOIO and GFP_NOFS even, GFP_ATOMIC.
> > I believe it's not trivial now.
>
> They're all buggy then. Unfortunately not through any real fault of their own.
There are gruesome problems in block/blk-throttle.c (thread "mempool,
percpu, blkcg: fix percpu stat allocation and remove stats_lock"). It
wants to do an alloc_percpu()->vmalloc() from the IO submission path,
under GFP_NOIO.
Changing vmalloc() to take a gfp_t does make lots of sense, although I
worry a bit about making vmalloc() easier to use!
I do wonder whether the whole scheme of explicitly passing a gfp_t was
a mistake and that the allocation context should be part of the task
context. ie: pass the allocation mode via *current. As a handy
side-effect that would probably save quite some code where functions
are receiving a gfp_t arg then simply passing it on to the next
callee.
next prev parent reply other threads:[~2012-04-24 21:30 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-23 8:55 [RFC] propagate gfp_t to page table alloc functions Minchan Kim
2012-04-24 5:16 ` KAMEZAWA Hiroyuki
2012-04-24 5:35 ` Minchan Kim
2012-04-24 6:13 ` Nick Piggin
2012-04-24 7:19 ` Minchan Kim
2012-04-24 7:48 ` Nick Piggin
2012-04-24 8:01 ` Minchan Kim
2012-04-24 8:05 ` Nick Piggin
2012-04-24 21:30 ` Andrew Morton [this message]
2012-04-24 23:49 ` KAMEZAWA Hiroyuki
2012-04-24 23:55 ` KOSAKI Motohiro
2012-04-25 0:05 ` KAMEZAWA Hiroyuki
2012-04-25 0:25 ` Andrew Morton
2012-04-26 0:05 ` KAMEZAWA Hiroyuki
2012-04-26 0:20 ` David Rientjes
2012-04-27 2:24 ` Minchan Kim
2012-04-27 3:08 ` Andrew Morton
2012-04-27 10:43 ` David Rientjes
2012-04-30 1:25 ` Minchan Kim
2012-05-01 7:20 ` Nick Piggin
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