From mboxrd@z Thu Jan 1 00:00:00 1970 From: Con Kolivas Subject: Re: Respin: [PATCH] mm: limit lowmem_reserve Date: Thu, 6 Apr 2006 14:36:16 +1000 References: <200604021401.13331.kernel@kolivas.org> <200604061258.40487.kernel@kolivas.org> <20060405204009.3235b021.akpm@osdl.org> In-Reply-To: <20060405204009.3235b021.akpm@osdl.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200604061436.16907.kernel@kolivas.org> Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: ck@vds.kolivas.org, nickpiggin@yahoo.com.au, linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On Thursday 06 April 2006 13:40, Andrew Morton wrote: > Con Kolivas wrote: > > On Thursday 06 April 2006 12:55, Con Kolivas wrote: > > > On Thursday 06 April 2006 12:43, Andrew Morton wrote: > > > > Con Kolivas wrote: > > > > > It is possible with a low enough lowmem_reserve ratio to make > > > > > zone_watermark_ok fail repeatedly if the lower_zone is small > > > > > enough. > > > > > > > > Is that actually a problem? > > > > > > Every single call to get_page_from_freelist will call on zone reclaim. > > > It seems a problem to me if every call to __alloc_pages will do that? > > > > every call to __alloc_pages of that zone I mean > > One would need to check with the NUMA guys. zone_reclaim() has a > (lame-looking) timer in there to prevent it from doing too much work. > > That, or I'm missing something. This problem wasn't particularly well > described, sorry. Ah ok. This all came about because I'm trying to honour the lowmem_reserve better in swap_prefetch at Nick's request. It's hard to honour a watermark that on some configurations is never reached. Cheers, Con -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org