From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 23 Jun 2008 09:00:48 +0100 From: Mel Gorman Subject: Re: [PATCH 2/2] hugetlb reservations: fix hugetlb MAP_PRIVATE reservations across vma splits Message-ID: <20080623080048.GJ21597@csn.ul.ie> References: <1213989474-5586-1-git-send-email-apw@shadowen.org> <1213989474-5586-3-git-send-email-apw@shadowen.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <1213989474-5586-3-git-send-email-apw@shadowen.org> Sender: owner-linux-mm@kvack.org Return-Path: To: Andy Whitcroft Cc: Jon Tollefson , Andrew Morton , Nick Piggin , Nishanth Aravamudan , Adam Litke , linux-kernel@vger.kernel.org, kernel-testers@vger.kernel.org, linux-mm@kvack.org List-ID: Typical. I spotted this after I pushed send..... > > @@ -266,14 +326,19 @@ static void decrement_hugepage_resv_vma(struct hstate *h, > * private mappings. > */ > if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { > - unsigned long flags, reserve; > + unsigned long idx = vma_pagecache_offset(h, > + vma, address); > + struct resv_map *reservations = vma_resv_map(vma); > + > h->resv_huge_pages--; > - flags = (unsigned long)vma->vm_private_data & > - HPAGE_RESV_MASK; > - reserve = (unsigned long)vma->vm_private_data - 1; > - vma->vm_private_data = (void *)(reserve | flags); > + > + /* Mark this page used in the map. */ > + if (region_chg(&reservations->regions, idx, idx + 1) < 0) > + return -1; > + region_add(&reservations->regions, idx, idx + 1); > } decrement_hugepage_resv_vma() is called with hugetlb_lock held and region_chg calls kmalloc(GFP_KERNEL). Hence it's possible we would sleep with that spinlock held which is a bit uncool. The allocation needs to happen outside the lock. Right? > -- Mel Gorman -- 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