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From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Andrea Arcangeli <andrea@suse.de>
Cc: Andrew Morton <akpm@osdl.org>,
	riel@redhat.com, marcelo.tosatti@cyclades.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH][5/?] count writeback pages in nr_scanned
Date: Thu, 06 Jan 2005 16:44:39 +1100	[thread overview]
Message-ID: <41DCD047.9050707@yahoo.com.au> (raw)
In-Reply-To: <41DCCE53.4000906@yahoo.com.au>

Nick Piggin wrote:
> Andrea Arcangeli wrote:
> 
>> On Thu, Jan 06, 2005 at 04:19:36PM +1100, Nick Piggin wrote:
>>
>>> This is practically what blk_congestion_wait does when the queue
>>> isn't congested though, isn't it?
>>
>>
>>
>> The fundamental difference that makes it reliable is that:
>>
>> 1) only the I/O we're throttling against will be considered for the
>>    wakeup event, which means only clearing PG_writeback will be
>>    considered eligible for wakeup
>>    Currently _all_ unrelated write I/O was considered eligible
>>    for wakeup events and that could cause spurious oom kills.
> 
> 
> I'm not entirely convinced. In Rik's case it didn't matter, because
> all his writeout was in the same zone that reclaim was happening
> against (ZONE_NORMAL), so in that case, PG_writeback throttling
> will do exactly the same thing as blk_congestion_wait.
> 
> I do like your PG_writeback throttling idea for the other reason
> that it should behave better on NUMA systems with lots of zones
> and lots of disks.
> 

... or Andrew's described fix. I think both would result in pretty
similar behaviour, but Andrew's is probably a bit nicer because it
doesn't require the scanner to have initiated the write.

  reply	other threads:[~2005-01-06  5:44 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-01-03 17:25 [PATCH][5/?] count writeback pages in nr_scanned Rik van Riel
2005-01-05 10:08 ` Andrew Morton
2005-01-05 18:06   ` Andrea Arcangeli
2005-01-05 18:50     ` Rik van Riel
2005-01-05 17:49       ` Marcelo Tosatti
2005-01-05 21:44         ` Andrew Morton
2005-01-05 20:32           ` Marcelo Tosatti
2005-01-05 23:51             ` Nick Piggin
2005-01-06  1:27               ` Rik van Riel
2005-01-06  1:33                 ` Nick Piggin
2005-01-06  1:37                   ` Andrew Morton
2005-01-06  1:40                     ` Nick Piggin
2005-01-06  1:52                       ` Andrea Arcangeli
2005-01-06  1:36                 ` Andrew Morton
2005-01-06  3:42                   ` Rik van Riel
2005-01-06  3:50                     ` Nick Piggin
2005-01-06  4:26                       ` Andrew Morton
2005-01-06  4:35                         ` Nick Piggin
2005-01-06  4:47                           ` Andrew Morton
2005-01-06  4:55                             ` Nick Piggin
2005-01-06  5:03                               ` Andrea Arcangeli
2005-01-06  8:06                               ` Jens Axboe
2005-01-06  8:16                                 ` memory barrier in ll_rw_blk.c (was Re: [PATCH][5/?] count writeback pages in nr_scanned) Nick Piggin
2005-01-06  8:32                                   ` Jens Axboe
2005-01-06  8:53                                     ` Nick Piggin
2005-01-06 12:00                                       ` Jens Axboe
2005-01-06  4:59                             ` [PATCH][5/?] count writeback pages in nr_scanned Andrea Arcangeli
2005-01-06  5:05                               ` Andrew Morton
2005-01-06  5:17                                 ` Andrea Arcangeli
2005-01-06  5:19                                   ` Nick Piggin
2005-01-06  5:25                                     ` Andrea Arcangeli
2005-01-06  5:36                                       ` Nick Piggin
2005-01-06  5:44                                         ` Nick Piggin [this message]
2005-01-06  5:37                                       ` Andrew Morton
2005-01-06  5:59                                         ` Andrea Arcangeli
2005-01-06 13:28                                         ` Rik van Riel
2005-01-06  5:32                                     ` Andrew Morton
2005-01-06  5:46                                       ` Andrea Arcangeli
2005-01-06  5:59                                         ` Andrew Morton
2005-01-06  6:16                                           ` Andrea Arcangeli
2005-01-06  5:06                               ` Nick Piggin
2005-01-06  5:21                                 ` Andrea Arcangeli
2005-01-05 23:26 ` Andrew Morton

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