From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx119.postini.com [74.125.245.119]) by kanga.kvack.org (Postfix) with SMTP id 3460C6B00EA for ; Fri, 27 Apr 2012 21:38:22 -0400 (EDT) Received: from /spool/local by e8.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 27 Apr 2012 21:38:20 -0400 Received: from d01relay06.pok.ibm.com (d01relay06.pok.ibm.com [9.56.227.116]) by d01dlp01.pok.ibm.com (Postfix) with ESMTP id 94C8238C803A for ; Fri, 27 Apr 2012 21:38:17 -0400 (EDT) Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by d01relay06.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q3S1cH8K25034858 for ; Fri, 27 Apr 2012 21:38:17 -0400 Received: from d01av02.pok.ibm.com (loopback [127.0.0.1]) by d01av02.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q3S1cH4G009693 for ; Fri, 27 Apr 2012 22:38:17 -0300 Date: Sat, 28 Apr 2012 09:38:02 +0800 From: Gavin Shan Subject: Re: [PATCH 2/2] MM: check limit while deallocating bootmem node Message-ID: <20120428013802.GA8061@shangw> Reply-To: Gavin Shan References: <1335498104-31900-1-git-send-email-shangw@linux.vnet.ibm.com> <1335498104-31900-2-git-send-email-shangw@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1335498104-31900-2-git-send-email-shangw@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: hannes@cmpxchg.org Cc: linux-mm@kvack.org Hi Johannes, Could you take a look on this while you have available time? Thanks, Gavin >For the particular bootmem node, the minimal and maximal PFN ( >Page Frame Number) have been traced in the instance of "struct >bootmem_data_t". On current implementation, the maximal PFN isn't >checked while deallocating a bunch (BITS_PER_LONG) of page frames. >So the current implementation won't work if the maximal PFN isn't >aligned with BITS_PER_LONG. > >The patch will check the maximal PFN of the given bootmem node. >Also, we needn't check all the bits map when the starting PFN isn't >BITS_PER_LONG aligned. Actually, we should start from the offset >of the bits map, which indicated by the starting PFN. > >Signed-off-by: Gavin Shan >--- > mm/bootmem.c | 11 ++++++++--- > 1 files changed, 8 insertions(+), 3 deletions(-) > >diff --git a/mm/bootmem.c b/mm/bootmem.c >index 5a04536..ebac3ba 100644 >--- a/mm/bootmem.c >+++ b/mm/bootmem.c >@@ -194,16 +194,20 @@ static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata) > * BITS_PER_LONG block of pages in front of us, free > * it in one go. > */ >- if (IS_ALIGNED(start, BITS_PER_LONG) && vec == ~0UL) { >+ if (end - start >= BITS_PER_LONG && >+ IS_ALIGNED(start, BITS_PER_LONG) && >+ vec == ~0UL) { > int order = ilog2(BITS_PER_LONG); > > __free_pages_bootmem(pfn_to_page(start), order); > count += BITS_PER_LONG; > start += BITS_PER_LONG; > } else { >- unsigned long off = 0; >+ unsigned long cursor = start; >+ unsigned long off = cursor & (BITS_PER_LONG - 1); > >- while (vec && off < BITS_PER_LONG) { >+ vec >>= off; >+ while (vec && off < BITS_PER_LONG && cursor < end) { > if (vec & 1) { > page = pfn_to_page(start + off); > __free_pages_bootmem(page, 0); >@@ -211,6 +215,7 @@ static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata) > } > vec >>= 1; > off++; >+ cursor++; > } > start = ALIGN(start + 1, BITS_PER_LONG); > } >-- >1.7.5.4 > -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org