From: Aaron Lu <aaron.lu@intel.com> To: Michal Hocko <mhocko@kernel.org> Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Dave Hansen <dave.hansen@intel.com>, Tim Chen <tim.c.chen@intel.com>, Andrew Morton <akpm@linux-foundation.org>, Ying Huang <ying.huang@intel.com> Subject: Re: [PATCH v2 0/5] mm: support parallel free of memory Date: Wed, 15 Mar 2017 23:44:07 +0800 [thread overview] Message-ID: <20170315154406.GF2442@aaronlu.sh.intel.com> (raw) In-Reply-To: <20170315141813.GB32626@dhcp22.suse.cz> On Wed, Mar 15, 2017 at 03:18:14PM +0100, Michal Hocko wrote: > On Wed 15-03-17 16:59:59, Aaron Lu wrote: > [...] > > The proposed parallel free did this: if the process has many pages to be > > freed, accumulate them in these struct mmu_gather_batch(es) one after > > another till 256K pages are accumulated. Then take this singly linked > > list starting from tlb->local.next off struct mmu_gather *tlb and free > > them in a worker thread. The main thread can return to continue zap > > other pages(after freeing pages pointed by tlb->local.pages). > > I didn't have a look at the implementation yet but there are two > concerns that raise up from this description. Firstly how are we going > to tune the number of workers. I assume there will be some upper bound > (one of the patch subject mentions debugfs for tuning) and secondly The workers are put in a dedicated workqueue which is introduced in patch 3/5 and the number of workers can be tuned through that workqueue's sysfs interface: max_active. > if we offload the page freeing to the worker then the original context > can consume much more cpu cycles than it was configured via cpu > controller. How are we going to handle that? Or is this considered > acceptable? I'll need to think about and take a look at this subject(not familiar with cpu controller). Thanks.
WARNING: multiple messages have this Message-ID (diff)
From: Aaron Lu <aaron.lu@intel.com> To: Michal Hocko <mhocko@kernel.org> Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Dave Hansen <dave.hansen@intel.com>, Tim Chen <tim.c.chen@intel.com>, Andrew Morton <akpm@linux-foundation.org>, Ying Huang <ying.huang@intel.com> Subject: Re: [PATCH v2 0/5] mm: support parallel free of memory Date: Wed, 15 Mar 2017 23:44:07 +0800 [thread overview] Message-ID: <20170315154406.GF2442@aaronlu.sh.intel.com> (raw) In-Reply-To: <20170315141813.GB32626@dhcp22.suse.cz> On Wed, Mar 15, 2017 at 03:18:14PM +0100, Michal Hocko wrote: > On Wed 15-03-17 16:59:59, Aaron Lu wrote: > [...] > > The proposed parallel free did this: if the process has many pages to be > > freed, accumulate them in these struct mmu_gather_batch(es) one after > > another till 256K pages are accumulated. Then take this singly linked > > list starting from tlb->local.next off struct mmu_gather *tlb and free > > them in a worker thread. The main thread can return to continue zap > > other pages(after freeing pages pointed by tlb->local.pages). > > I didn't have a look at the implementation yet but there are two > concerns that raise up from this description. Firstly how are we going > to tune the number of workers. I assume there will be some upper bound > (one of the patch subject mentions debugfs for tuning) and secondly The workers are put in a dedicated workqueue which is introduced in patch 3/5 and the number of workers can be tuned through that workqueue's sysfs interface: max_active. > if we offload the page freeing to the worker then the original context > can consume much more cpu cycles than it was configured via cpu > controller. How are we going to handle that? Or is this considered > acceptable? I'll need to think about and take a look at this subject(not familiar with cpu controller). Thanks. -- 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:[~2017-03-15 15:44 UTC|newest] Thread overview: 84+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-03-15 8:59 [PATCH v2 0/5] mm: support parallel free of memory Aaron Lu 2017-03-15 8:59 ` Aaron Lu 2017-03-15 9:00 ` [PATCH v2 1/5] mm: add tlb_flush_mmu_free_batches Aaron Lu 2017-03-15 9:00 ` Aaron Lu 2017-03-15 9:00 ` [PATCH v2 2/5] mm: parallel free pages Aaron Lu 2017-03-15 9:00 ` Aaron Lu 2017-03-15 9:42 ` Hillf Danton 2017-03-15 9:42 ` Hillf Danton 2017-03-15 11:54 ` Aaron Lu 2017-03-15 11:54 ` Aaron Lu 2017-03-15 9:00 ` [PATCH v2 3/5] mm: use a dedicated workqueue for the free workers Aaron Lu 2017-03-15 9:00 ` Aaron Lu 2017-03-22 6:33 ` Minchan Kim 2017-03-22 6:33 ` Minchan Kim 2017-03-22 8:41 ` Aaron Lu 2017-03-22 8:41 ` Aaron Lu 2017-03-22 8:55 ` Minchan Kim 2017-03-22 8:55 ` Minchan Kim 2017-03-22 13:43 ` Aaron Lu 2017-03-22 13:43 ` Aaron Lu 2017-03-23 5:53 ` Minchan Kim 2017-03-23 5:53 ` Minchan Kim 2017-03-23 15:38 ` Dave Hansen 2017-03-23 15:38 ` Dave Hansen 2017-03-24 12:37 ` Aaron Lu 2017-03-24 12:37 ` Aaron Lu 2017-03-15 9:00 ` [PATCH v2 4/5] mm: add force_free_pages in zap_pte_range Aaron Lu 2017-03-15 9:00 ` Aaron Lu 2017-03-15 9:00 ` [PATCH v2 5/5] mm: add debugfs interface for parallel free tuning Aaron Lu 2017-03-15 9:00 ` Aaron Lu 2017-03-15 14:18 ` [PATCH v2 0/5] mm: support parallel free of memory Michal Hocko 2017-03-15 14:18 ` Michal Hocko 2017-03-15 15:44 ` Aaron Lu [this message] 2017-03-15 15:44 ` Aaron Lu 2017-03-15 16:28 ` Michal Hocko 2017-03-15 16:28 ` Michal Hocko 2017-03-15 21:38 ` Tim Chen 2017-03-15 21:38 ` Tim Chen 2017-03-16 9:07 ` Michal Hocko 2017-03-16 9:07 ` Michal Hocko 2017-03-16 18:36 ` Tim Chen 2017-03-16 18:36 ` Tim Chen 2017-03-17 7:47 ` Michal Hocko 2017-03-17 7:47 ` Michal Hocko 2017-03-17 8:07 ` Minchan Kim 2017-03-17 8:07 ` Minchan Kim 2017-03-17 12:33 ` Aaron Lu 2017-03-17 12:33 ` Aaron Lu 2017-03-17 12:59 ` Michal Hocko 2017-03-17 12:59 ` Michal Hocko 2017-03-17 13:16 ` Peter Zijlstra 2017-03-17 13:16 ` Peter Zijlstra 2017-03-17 12:53 ` Peter Zijlstra 2017-03-17 12:53 ` Peter Zijlstra 2017-03-17 13:05 ` Michal Hocko 2017-03-17 13:05 ` Michal Hocko 2017-03-21 14:54 ` Dave Hansen 2017-03-21 14:54 ` Dave Hansen 2017-03-22 8:02 ` Aaron Lu 2017-03-22 8:02 ` Aaron Lu 2017-03-24 7:04 ` Aaron Lu 2017-03-24 7:04 ` Aaron Lu 2017-03-21 15:18 ` Tim Chen 2017-03-21 15:18 ` Tim Chen 2017-03-16 6:54 ` Aaron Lu 2017-03-16 6:54 ` Aaron Lu 2017-03-16 7:34 ` Aaron Lu 2017-03-16 7:34 ` Aaron Lu 2017-03-16 13:51 ` Aaron Lu 2017-03-16 13:51 ` Aaron Lu 2017-03-16 14:14 ` Aaron Lu 2017-03-16 14:14 ` Aaron Lu 2017-03-15 14:56 ` Vlastimil Babka 2017-03-15 14:56 ` Vlastimil Babka 2017-03-15 15:50 ` Aaron Lu 2017-03-15 15:50 ` Aaron Lu 2017-03-17 3:10 ` Aaron Lu 2017-03-17 3:10 ` Aaron Lu 2017-03-16 19:38 ` Alex Thorlton 2017-03-16 19:38 ` Alex Thorlton 2017-03-17 2:21 ` Aaron Lu 2017-03-17 2:21 ` Aaron Lu 2017-03-20 19:15 ` Alex Thorlton 2017-03-20 19:15 ` Alex Thorlton
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