From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx147.postini.com [74.125.245.147]) by kanga.kvack.org (Postfix) with SMTP id 5B98E6B13F1 for ; Wed, 1 Feb 2012 17:43:54 -0500 (EST) Date: Wed, 1 Feb 2012 14:43:53 -0800 From: Andrew Morton Subject: Re: [PATCH 3/5] hugetlb: try to search again if it is really needed Message-Id: <20120201144353.7c75b5b6.akpm@linux-foundation.org> In-Reply-To: <4F101969.8050601@linux.vnet.ibm.com> References: <4F101904.8090405@linux.vnet.ibm.com> <4F101969.8050601@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Xiao Guangrong Cc: William Irwin , linux-mm@kvack.org, LKML On Fri, 13 Jan 2012 19:45:45 +0800 Xiao Guangrong wrote: > Search again only if some holes may be skipped in the first time > > Signed-off-by: Xiao Guangrong > --- > arch/x86/mm/hugetlbpage.c | 8 ++++---- > 1 files changed, 4 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c > index e12debc..6bf5735 100644 > --- a/arch/x86/mm/hugetlbpage.c > +++ b/arch/x86/mm/hugetlbpage.c > @@ -309,9 +309,8 @@ static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file, > struct hstate *h = hstate_file(file); > struct mm_struct *mm = current->mm; > struct vm_area_struct *vma; > - unsigned long base = mm->mmap_base, addr = addr0; > + unsigned long base = mm->mmap_base, addr = addr0, start_addr; grr. The multiple-definitions-per-line thing is ugly, makes for more patch conflicts and reduces opportunities to add useful comments. --- a/arch/x86/mm/hugetlbpage.c~hugetlb-try-to-search-again-if-it-is-really-needed-fix +++ a/arch/x86/mm/hugetlbpage.c @@ -309,7 +309,9 @@ static unsigned long hugetlb_get_unmappe struct hstate *h = hstate_file(file); struct mm_struct *mm = current->mm; struct vm_area_struct *vma; - unsigned long base = mm->mmap_base, addr = addr0, start_addr; + unsigned long base = mm->mmap_base; + unsigned long addr = addr0; + unsigned long start_addr; unsigned long largest_hole = mm->cached_hole_size; /* don't allow allocations above current base */ _ > unsigned long largest_hole = mm->cached_hole_size; > - int first_time = 1; > > /* don't allow allocations above current base */ > if (mm->free_area_cache > base) > @@ -322,6 +321,8 @@ static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file, > mm->free_area_cache = base; > } > try_again: > + start_addr = mm->free_area_cache; > + > /* make sure it can fit in the remaining address space */ > if (mm->free_area_cache < len) > goto fail; > @@ -357,10 +358,9 @@ fail: > * if hint left us with no space for the requested > * mapping then try again: > */ > - if (first_time) { > + if (start_addr != base) { > mm->free_area_cache = base; > largest_hole = 0; > - first_time = 0; > goto try_again; The code used to retry a single time. With this change the retrying is potentially infinite. What is the reason for this change? What is the potential for causing a lockup? -- 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