From: Nikanth Karthikesan <knikanth@suse.de> To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Richard Guenther <rguenther@suse.de>, linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>, balbir@linux.vnet.ibm.com, Michael Matz <matz@novell.com>, Matt Mackall <mpm@selenic.com>, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] After swapout/swapin private dirty mappings are reported clean in smaps Date: Wed, 15 Sep 2010 12:01:11 +0530 [thread overview] Message-ID: <201009151201.11359.knikanth@suse.de> (raw) In-Reply-To: <20100915141710.C9F7.A69D9226@jp.fujitsu.com> On Wednesday 15 September 2010 10:50:25 KOSAKI Motohiro wrote: > > On Wednesday 15 September 2010 10:18:11 KOSAKI Motohiro wrote: > > > > On Wednesday 15 September 2010 05:56:36 KOSAKI Motohiro wrote: > > > > > > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > > > > > > index 439fc1f..06fc468 100644 > > > > > > --- a/fs/proc/task_mmu.c > > > > > > +++ b/fs/proc/task_mmu.c > > > > > > @@ -368,7 +368,11 @@ static int smaps_pte_range(pmd_t *pmd, > > > > > > unsigned long addr, unsigned long end, mss->shared_clean += > > > > > > PAGE_SIZE; mss->pss += (PAGE_SIZE << PSS_SHIFT) / mapcount; > > > > > > } else { > > > > > > - if (pte_dirty(ptent)) > > > > > > + /* > > > > > > + * File-backed pages, now anonymous are dirty > > > > > > + * with respect to the file. > > > > > > + */ > > > > > > + if (pte_dirty(ptent) || (vma->vm_file && PageAnon(page))) > > > > > > mss->private_dirty += PAGE_SIZE; > > > > > > else > > > > > > mss->private_clean += PAGE_SIZE; > > > > > > > > > > This is risky than v1. number of dirties are used a lot of > > > > > application. > > > > > > > > This is exactly to help those applications, as currently after > > > > swap-out and swap-in, the same pages are accounted as > > > > "Private_Clean:" instead of "Private_Dirty:". > > > > > > I don't think so. > > > > Actually this behaviour is observed. With a simple memhog, you can see > > pages which are "Private_Dirty:", become "Swap:" and then to > > "Private_Clean:". And that confused GDB. > > As I said, incorrect information is always no good solustion. We should > concern how to provide good and enough information, but not how to lie. > If currect gdb is crappy, it should fix. > How? Current smaps information without this patch provides incorrect information. Just because a private dirty page became part of swap cache, it shown as clean and backed by a file. If it is shown as clean and backed by swap then it is fine. Thanks Nikanth > > > incorrect infomation bring a lot of confusion rather than > > > its worth. >
WARNING: multiple messages have this Message-ID (diff)
From: Nikanth Karthikesan <knikanth@suse.de> To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Richard Guenther <rguenther@suse.de>, linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>, balbir@linux.vnet.ibm.com, Michael Matz <matz@novell.com>, Matt Mackall <mpm@selenic.com>, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] After swapout/swapin private dirty mappings are reported clean in smaps Date: Wed, 15 Sep 2010 12:01:11 +0530 [thread overview] Message-ID: <201009151201.11359.knikanth@suse.de> (raw) In-Reply-To: <20100915141710.C9F7.A69D9226@jp.fujitsu.com> On Wednesday 15 September 2010 10:50:25 KOSAKI Motohiro wrote: > > On Wednesday 15 September 2010 10:18:11 KOSAKI Motohiro wrote: > > > > On Wednesday 15 September 2010 05:56:36 KOSAKI Motohiro wrote: > > > > > > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > > > > > > index 439fc1f..06fc468 100644 > > > > > > --- a/fs/proc/task_mmu.c > > > > > > +++ b/fs/proc/task_mmu.c > > > > > > @@ -368,7 +368,11 @@ static int smaps_pte_range(pmd_t *pmd, > > > > > > unsigned long addr, unsigned long end, mss->shared_clean += > > > > > > PAGE_SIZE; mss->pss += (PAGE_SIZE << PSS_SHIFT) / mapcount; > > > > > > } else { > > > > > > - if (pte_dirty(ptent)) > > > > > > + /* > > > > > > + * File-backed pages, now anonymous are dirty > > > > > > + * with respect to the file. > > > > > > + */ > > > > > > + if (pte_dirty(ptent) || (vma->vm_file && PageAnon(page))) > > > > > > mss->private_dirty += PAGE_SIZE; > > > > > > else > > > > > > mss->private_clean += PAGE_SIZE; > > > > > > > > > > This is risky than v1. number of dirties are used a lot of > > > > > application. > > > > > > > > This is exactly to help those applications, as currently after > > > > swap-out and swap-in, the same pages are accounted as > > > > "Private_Clean:" instead of "Private_Dirty:". > > > > > > I don't think so. > > > > Actually this behaviour is observed. With a simple memhog, you can see > > pages which are "Private_Dirty:", become "Swap:" and then to > > "Private_Clean:". And that confused GDB. > > As I said, incorrect information is always no good solustion. We should > concern how to provide good and enough information, but not how to lie. > If currect gdb is crappy, it should fix. > How? Current smaps information without this patch provides incorrect information. Just because a private dirty page became part of swap cache, it shown as clean and backed by a file. If it is shown as clean and backed by swap then it is fine. Thanks Nikanth > > > incorrect infomation bring a lot of confusion rather than > > > its worth. > -- 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: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2010-09-15 6:28 UTC|newest] Thread overview: 86+ messages / expand[flat|nested] mbox.gz Atom feed top 2010-09-14 11:10 [PATCH] After swapout/swapin private dirty mappings become clean Nikanth Karthikesan 2010-09-14 11:10 ` Nikanth Karthikesan 2010-09-14 11:33 ` Richard Guenther 2010-09-14 11:33 ` Richard Guenther 2010-09-14 17:12 ` Nikanth Karthikesan 2010-09-14 17:12 ` Nikanth Karthikesan 2010-09-14 17:14 ` [PATCH v2] After swapout/swapin private dirty mappings are reported clean in smaps Nikanth Karthikesan 2010-09-14 17:14 ` Nikanth Karthikesan 2010-09-15 0:26 ` KOSAKI Motohiro 2010-09-15 0:26 ` KOSAKI Motohiro 2010-09-15 4:38 ` Nikanth Karthikesan 2010-09-15 4:38 ` Nikanth Karthikesan 2010-09-15 4:48 ` KOSAKI Motohiro 2010-09-15 4:48 ` KOSAKI Motohiro 2010-09-15 5:04 ` Nikanth Karthikesan 2010-09-15 5:04 ` Nikanth Karthikesan 2010-09-15 5:20 ` KOSAKI Motohiro 2010-09-15 5:20 ` KOSAKI Motohiro 2010-09-15 6:31 ` Nikanth Karthikesan [this message] 2010-09-15 6:31 ` Nikanth Karthikesan 2010-09-15 14:09 ` Balbir Singh 2010-09-15 14:09 ` Balbir Singh 2010-09-15 14:14 ` Richard Guenther 2010-09-15 14:14 ` Richard Guenther 2010-09-15 14:46 ` Matt Mackall 2010-09-15 14:46 ` Matt Mackall 2010-09-15 14:53 ` Richard Guenther 2010-09-15 14:53 ` Richard Guenther 2010-09-15 17:24 ` Matt Mackall 2010-09-15 17:24 ` Matt Mackall 2010-09-15 19:08 ` Richard Guenther 2010-09-15 19:08 ` Richard Guenther 2010-09-15 19:18 ` Hugh Dickins 2010-09-15 19:18 ` Hugh Dickins 2010-09-15 19:46 ` Matt Mackall 2010-09-15 19:46 ` Matt Mackall 2010-09-15 19:53 ` Richard Guenther 2010-09-15 19:53 ` Richard Guenther 2010-09-15 21:47 ` Hugh Dickins 2010-09-15 21:47 ` Hugh Dickins 2010-09-16 3:26 ` [PATCH] Export amount of anonymous memory in a mapping via smaps Nikanth Karthikesan 2010-09-16 3:26 ` Nikanth Karthikesan 2010-09-16 3:52 ` KOSAKI Motohiro 2010-09-16 3:52 ` KOSAKI Motohiro 2010-09-16 6:04 ` [PATCH] Document the new Anonymous field in smaps Nikanth Karthikesan 2010-09-16 6:04 ` Nikanth Karthikesan 2010-09-16 6:34 ` [PATCH] smaps: fix dirty pages accounting KOSAKI Motohiro 2010-09-16 6:34 ` KOSAKI Motohiro 2010-09-16 16:56 ` Hugh Dickins 2010-09-16 16:56 ` Hugh Dickins 2010-09-16 16:50 ` [PATCH] Document the new Anonymous field in smaps Hugh Dickins 2010-09-17 6:04 ` [PATCH v2] " Nikanth Karthikesan 2010-09-17 6:04 ` Nikanth Karthikesan 2010-09-20 7:11 ` Hugh Dickins 2010-09-20 19:24 ` Matt Mackall 2010-09-20 19:24 ` Matt Mackall 2010-09-16 16:40 ` [PATCH] Export amount of anonymous memory in a mapping via smaps Hugh Dickins 2010-09-16 16:40 ` Hugh Dickins 2010-09-15 17:41 ` [PATCH v2] After swapout/swapin private dirty mappings are reported clean in smaps Balbir Singh 2010-09-15 17:41 ` Balbir Singh 2010-09-19 17:37 ` Nikanth Karthikesan 2010-09-19 17:37 ` Nikanth Karthikesan 2010-09-19 17:38 ` [PATCH] Document /proc/pid/pagemap in Documentation/filesystems/proc.txt Nikanth Karthikesan 2010-09-19 17:38 ` Nikanth Karthikesan 2010-09-20 21:27 ` Matt Mackall 2010-09-20 21:27 ` Matt Mackall 2010-09-20 5:24 ` [PATCH v2] After swapout/swapin private dirty mappings are reported clean in smaps Nikanth Karthikesan 2010-09-20 5:24 ` Nikanth Karthikesan 2010-09-20 14:30 ` Richard Guenther 2010-09-20 14:30 ` Richard Guenther 2010-09-15 0:24 ` [PATCH] After swapout/swapin private dirty mappings become clean KOSAKI Motohiro 2010-09-15 0:24 ` KOSAKI Motohiro 2010-09-15 4:37 ` Nikanth Karthikesan 2010-09-15 4:37 ` Nikanth Karthikesan 2010-09-15 4:46 ` KOSAKI Motohiro 2010-09-15 4:46 ` KOSAKI Motohiro 2010-09-15 5:00 ` Nikanth Karthikesan 2010-09-15 5:00 ` Nikanth Karthikesan 2010-09-15 5:15 ` KOSAKI Motohiro 2010-09-15 5:15 ` KOSAKI Motohiro 2010-09-15 6:29 ` Nikanth Karthikesan 2010-09-15 6:29 ` Nikanth Karthikesan 2010-09-15 8:40 ` Richard Guenther 2010-09-15 8:40 ` Richard Guenther 2010-09-16 1:29 ` KOSAKI Motohiro 2010-09-16 1:29 ` KOSAKI Motohiro
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