From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx183.postini.com [74.125.245.183]) by kanga.kvack.org (Postfix) with SMTP id E65CB6B0044 for ; Mon, 30 Apr 2012 11:26:00 -0400 (EDT) From: Naoya Horiguchi Subject: Re: [PATCH bugfix] proc/pagemap: correctly report non-present ptes and holes between vmas Date: Mon, 30 Apr 2012 11:25:42 -0400 Message-Id: <1335799542-8159-1-git-send-email-n-horiguchi@ah.jp.nec.com> In-Reply-To: <20120428162229.15658.56316.stgit@zurg> Sender: owner-linux-mm@kvack.org List-ID: To: khlebnikov@openvz.org Cc: Andrew Morton , ak@linux.intel.com, xemul@parallels.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Naoya Horiguchi , KAMEZAWA Hiroyuki Hi, On Sat, Apr 28, 2012 at 08:22:30PM +0400, Konstantin Khlebnikov wrote: > This patch resets current pagemap-entry if current pte isn't present, > or if current vma is over. Otherwise pagemap reports last entry again and again. > > non-present pte reporting was broken in commit v3.3-3738-g092b50b > ("pagemap: introduce data structure for pagemap entry") > > reporting for holes was broken in commit v3.3-3734-g5aaabe8 > ("pagemap: avoid splitting thp when reading /proc/pid/pagemap") > > Signed-off-by: Konstantin Khlebnikov > Reported-by: Pavel Emelyanov > Cc: Naoya Horiguchi > Cc: KAMEZAWA Hiroyuki > Cc: Andi Kleen Thanks for your efforts. I confirmed that this patch fixes the problem on v3.4-rc4. But originally (before the commits you pointed to above) initializing pagemap entries (originally labelled with confusing 'pfn') were done in for-loop in pagemap_pte_range(), so I think it's better to get it back to things like that. How about the following? --- diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 2b9a760..538f8d8 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -779,13 +779,14 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, struct pagemapread *pm = walk->private; pte_t *pte; int err = 0; - pagemap_entry_t pme = make_pme(PM_NOT_PRESENT); + pagemap_entry_t pme; /* find the first VMA at or above 'addr' */ vma = find_vma(walk->mm, addr); if (pmd_trans_huge_lock(pmd, vma) == 1) { for (; addr != end; addr += PAGE_SIZE) { unsigned long offset; + pme = make_pme(PM_NOT_PRESENT); offset = (addr & ~PAGEMAP_WALK_MASK) >> PAGE_SHIFT; @@ -801,6 +802,7 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, if (pmd_trans_unstable(pmd)) return 0; for (; addr != end; addr += PAGE_SIZE) { + pme = make_pme(PM_NOT_PRESENT); /* check to see if we've left 'vma' behind * and need a new, higher one */ @@ -842,10 +844,10 @@ static int pagemap_hugetlb_range(pte_t *pte, unsigned long hmask, { struct pagemapread *pm = walk->private; int err = 0; - pagemap_entry_t pme = make_pme(PM_NOT_PRESENT); for (; addr != end; addr += PAGE_SIZE) { int offset = (addr & ~hmask) >> PAGE_SHIFT; + pagemap_entry_t pme = make_pme(PM_NOT_PRESENT); huge_pte_to_pagemap_entry(&pme, *pte, offset); err = add_to_pagemap(addr, &pme, pm); if (err) --- Thanks, Naoya -- 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