From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757191Ab3GLHqC (ORCPT ); Fri, 12 Jul 2013 03:46:02 -0400 Received: from relay2.sgi.com ([192.48.179.30]:39051 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756798Ab3GLHqB (ORCPT ); Fri, 12 Jul 2013 03:46:01 -0400 Date: Fri, 12 Jul 2013 02:45:58 -0500 From: Robin Holt To: "H. Peter Anvin" , Ingo Molnar Cc: Robin Holt , Nate Zimmer , Linux Kernel , Linux MM , Rob Landley , Mike Travis , Daniel J Blueman , Andrew Morton , Greg KH , Yinghai Lu , Mel Gorman Subject: Re: [RFC 2/4] Have __free_pages_memory() free in larger chunks. Message-ID: <20130712074558.GP18798@sgi.com> References: <1373594635-131067-1-git-send-email-holt@sgi.com> <1373594635-131067-3-git-send-email-holt@sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1373594635-131067-3-git-send-email-holt@sgi.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org After sleeping on this, why can't we change __free_pages_bootmem to not take an order, but rather nr_pages? If we did that, then __free_pages_memory could just calculate nr_pages and call __free_pages_bootmem one time. I don't see why any of the callers of __free_pages_bootmem would not easily support that change. Maybe I will work that up as part of a -v2 and see if it boots/runs. At the very least, I think we could change to: static void __init __free_pages_memory(unsigned long start, unsigned long end) { int order; while (start < end) { order = ffs(start); while (start + (1UL << order) > end) order--; __free_pages_bootmem(start, order); start += (1UL << order); } } Robin On Thu, Jul 11, 2013 at 09:03:53PM -0500, Robin Holt wrote: > Currently, when free_all_bootmem() calls __free_pages_memory(), the > number of contiguous pages that __free_pages_memory() passes to the > buddy allocator is limited to BITS_PER_LONG. In order to be able to > free only the first page of a 2MiB chunk, we need that to be increased > to PTRS_PER_PMD. > > Signed-off-by: Robin Holt > Signed-off-by: Nate Zimmer > To: "H. Peter Anvin" > To: Ingo Molnar > Cc: Linux Kernel > Cc: Linux MM > Cc: Rob Landley > Cc: Mike Travis > Cc: Daniel J Blueman > Cc: Andrew Morton > Cc: Greg KH > Cc: Yinghai Lu > Cc: Mel Gorman > --- > mm/nobootmem.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/mm/nobootmem.c b/mm/nobootmem.c > index bdd3fa2..3b512ca 100644 > --- a/mm/nobootmem.c > +++ b/mm/nobootmem.c > @@ -83,10 +83,10 @@ void __init free_bootmem_late(unsigned long addr, unsigned long size) > static void __init __free_pages_memory(unsigned long start, unsigned long end) > { > unsigned long i, start_aligned, end_aligned; > - int order = ilog2(BITS_PER_LONG); > + int order = ilog2(max(BITS_PER_LONG, PTRS_PER_PMD)); > > - start_aligned = (start + (BITS_PER_LONG - 1)) & ~(BITS_PER_LONG - 1); > - end_aligned = end & ~(BITS_PER_LONG - 1); > + start_aligned = (start + ((1UL << order) - 1)) & ~((1UL << order) - 1); > + end_aligned = end & ~((1UL << order) - 1); > > if (end_aligned <= start_aligned) { > for (i = start; i < end; i++) > @@ -98,7 +98,7 @@ static void __init __free_pages_memory(unsigned long start, unsigned long end) > for (i = start; i < start_aligned; i++) > __free_pages_bootmem(pfn_to_page(i), 0); > > - for (i = start_aligned; i < end_aligned; i += BITS_PER_LONG) > + for (i = start_aligned; i < end_aligned; i += 1 << order) > __free_pages_bootmem(pfn_to_page(i), order); > > for (i = end_aligned; i < end; i++) > -- > 1.8.2.1 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx185.postini.com [74.125.245.185]) by kanga.kvack.org (Postfix) with SMTP id 3D3E46B0032 for ; Fri, 12 Jul 2013 03:46:01 -0400 (EDT) Date: Fri, 12 Jul 2013 02:45:58 -0500 From: Robin Holt Subject: Re: [RFC 2/4] Have __free_pages_memory() free in larger chunks. Message-ID: <20130712074558.GP18798@sgi.com> References: <1373594635-131067-1-git-send-email-holt@sgi.com> <1373594635-131067-3-git-send-email-holt@sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1373594635-131067-3-git-send-email-holt@sgi.com> Sender: owner-linux-mm@kvack.org List-ID: To: "H. Peter Anvin" , Ingo Molnar Cc: Robin Holt , Nate Zimmer , Linux Kernel , Linux MM , Rob Landley , Mike Travis , Daniel J Blueman , Andrew Morton , Greg KH , Yinghai Lu , Mel Gorman After sleeping on this, why can't we change __free_pages_bootmem to not take an order, but rather nr_pages? If we did that, then __free_pages_memory could just calculate nr_pages and call __free_pages_bootmem one time. I don't see why any of the callers of __free_pages_bootmem would not easily support that change. Maybe I will work that up as part of a -v2 and see if it boots/runs. At the very least, I think we could change to: static void __init __free_pages_memory(unsigned long start, unsigned long end) { int order; while (start < end) { order = ffs(start); while (start + (1UL << order) > end) order--; __free_pages_bootmem(start, order); start += (1UL << order); } } Robin On Thu, Jul 11, 2013 at 09:03:53PM -0500, Robin Holt wrote: > Currently, when free_all_bootmem() calls __free_pages_memory(), the > number of contiguous pages that __free_pages_memory() passes to the > buddy allocator is limited to BITS_PER_LONG. In order to be able to > free only the first page of a 2MiB chunk, we need that to be increased > to PTRS_PER_PMD. > > Signed-off-by: Robin Holt > Signed-off-by: Nate Zimmer > To: "H. Peter Anvin" > To: Ingo Molnar > Cc: Linux Kernel > Cc: Linux MM > Cc: Rob Landley > Cc: Mike Travis > Cc: Daniel J Blueman > Cc: Andrew Morton > Cc: Greg KH > Cc: Yinghai Lu > Cc: Mel Gorman > --- > mm/nobootmem.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/mm/nobootmem.c b/mm/nobootmem.c > index bdd3fa2..3b512ca 100644 > --- a/mm/nobootmem.c > +++ b/mm/nobootmem.c > @@ -83,10 +83,10 @@ void __init free_bootmem_late(unsigned long addr, unsigned long size) > static void __init __free_pages_memory(unsigned long start, unsigned long end) > { > unsigned long i, start_aligned, end_aligned; > - int order = ilog2(BITS_PER_LONG); > + int order = ilog2(max(BITS_PER_LONG, PTRS_PER_PMD)); > > - start_aligned = (start + (BITS_PER_LONG - 1)) & ~(BITS_PER_LONG - 1); > - end_aligned = end & ~(BITS_PER_LONG - 1); > + start_aligned = (start + ((1UL << order) - 1)) & ~((1UL << order) - 1); > + end_aligned = end & ~((1UL << order) - 1); > > if (end_aligned <= start_aligned) { > for (i = start; i < end; i++) > @@ -98,7 +98,7 @@ static void __init __free_pages_memory(unsigned long start, unsigned long end) > for (i = start; i < start_aligned; i++) > __free_pages_bootmem(pfn_to_page(i), 0); > > - for (i = start_aligned; i < end_aligned; i += BITS_PER_LONG) > + for (i = start_aligned; i < end_aligned; i += 1 << order) > __free_pages_bootmem(pfn_to_page(i), order); > > for (i = end_aligned; i < end; i++) > -- > 1.8.2.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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