From: Tejun Heo <tj@kernel.org> To: Andrew Morton <akpm@linux-foundation.org> Cc: Chris Metcalf <cmetcalf@tilera.com>, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Thomas Gleixner <tglx@linutronix.de>, Frederic Weisbecker <fweisbec@gmail.com>, Cody P Schafer <cody@linux.vnet.ibm.com> Subject: Re: [PATCH v4 2/2] mm: make lru_add_drain_all() selective Date: Tue, 13 Aug 2013 19:03:52 -0400 [thread overview] Message-ID: <20130813230352.GH28996@mtj.dyndns.org> (raw) In-Reply-To: <20130813154740.5daa053df87dd0358bbbab35@linux-foundation.org> Hello, Andrew. On Tue, Aug 13, 2013 at 03:47:40PM -0700, Andrew Morton wrote: > > Well, I don't buy that either. Callback based interface has its > > issues. > > No it hasn't. It's a common and simple technique which we all understand. It sure has its uses but it has receded some of its former use cases to better constructs which are easier to use and maintain. I'm not saying it's black and white here as the thing is callback based anyway but was trying to point out general disadvantages of callback based interface. If you're saying callback based interface isn't clunkier compared to constructs which can be embedded in the caller side, this discussion probably won't be very fruitful. > It's a relatively small improvement in the lru_add_drain_all() case. > Other callsites can gain improvements as well. Well, if we're talking about minute performance differences, for non-huge configurations, it'll actually be a small performance degradation as there will be more instructions and the control will be jumping back and forth. > It results in superior runtime code. At this and potentially other > callsites. It's actually inferior in majority of cases. > It does buy us things, as I've repeatedly described. You keep on > saying things which demonstrably aren't so. I think I'll give up now. I just don't think it's something clear cut and it doesn't even matter for the problem at hand. Let's please talk about how to solve the actual problem. Thanks. -- tejun
WARNING: multiple messages have this Message-ID (diff)
From: Tejun Heo <tj@kernel.org> To: Andrew Morton <akpm@linux-foundation.org> Cc: Chris Metcalf <cmetcalf@tilera.com>, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Thomas Gleixner <tglx@linutronix.de>, Frederic Weisbecker <fweisbec@gmail.com>, Cody P Schafer <cody@linux.vnet.ibm.com> Subject: Re: [PATCH v4 2/2] mm: make lru_add_drain_all() selective Date: Tue, 13 Aug 2013 19:03:52 -0400 [thread overview] Message-ID: <20130813230352.GH28996@mtj.dyndns.org> (raw) In-Reply-To: <20130813154740.5daa053df87dd0358bbbab35@linux-foundation.org> Hello, Andrew. On Tue, Aug 13, 2013 at 03:47:40PM -0700, Andrew Morton wrote: > > Well, I don't buy that either. Callback based interface has its > > issues. > > No it hasn't. It's a common and simple technique which we all understand. It sure has its uses but it has receded some of its former use cases to better constructs which are easier to use and maintain. I'm not saying it's black and white here as the thing is callback based anyway but was trying to point out general disadvantages of callback based interface. If you're saying callback based interface isn't clunkier compared to constructs which can be embedded in the caller side, this discussion probably won't be very fruitful. > It's a relatively small improvement in the lru_add_drain_all() case. > Other callsites can gain improvements as well. Well, if we're talking about minute performance differences, for non-huge configurations, it'll actually be a small performance degradation as there will be more instructions and the control will be jumping back and forth. > It results in superior runtime code. At this and potentially other > callsites. It's actually inferior in majority of cases. > It does buy us things, as I've repeatedly described. You keep on > saying things which demonstrably aren't so. I think I'll give up now. I just don't think it's something clear cut and it doesn't even matter for the problem at hand. Let's please talk about how to solve the actual problem. Thanks. -- tejun -- 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:[~2013-08-13 23:03 UTC|newest] Thread overview: 104+ messages / expand[flat|nested] mbox.gz Atom feed top 2013-08-06 20:22 [PATCH] mm: make lru_add_drain_all() selective Chris Metcalf 2013-08-06 20:22 ` Chris Metcalf 2013-08-06 20:22 ` [PATCH v2] " Chris Metcalf 2013-08-06 20:22 ` Chris Metcalf 2013-08-07 20:45 ` Tejun Heo 2013-08-07 20:45 ` Tejun Heo 2013-08-07 20:49 ` [PATCH v3 1/2] workqueue: add new schedule_on_cpu_mask() API Chris Metcalf 2013-08-07 20:49 ` Chris Metcalf 2013-08-07 20:52 ` [PATCH v3 2/2] mm: make lru_add_drain_all() selective Chris Metcalf 2013-08-07 20:52 ` Chris Metcalf 2013-08-07 22:48 ` [PATCH v2] " Cody P Schafer 2013-08-07 22:48 ` Cody P Schafer 2013-08-07 20:49 ` [PATCH v4 1/2] workqueue: add new schedule_on_cpu_mask() API Chris Metcalf 2013-08-07 20:49 ` Chris Metcalf 2013-08-09 15:02 ` Tejun Heo 2013-08-09 15:02 ` Tejun Heo 2013-08-09 16:12 ` Chris Metcalf 2013-08-09 16:12 ` Chris Metcalf 2013-08-09 16:30 ` Tejun Heo 2013-08-09 16:30 ` Tejun Heo 2013-08-07 20:49 ` [PATCH v5 " Chris Metcalf 2013-08-07 20:49 ` Chris Metcalf 2013-08-09 17:40 ` Tejun Heo 2013-08-09 17:40 ` Tejun Heo 2013-08-09 17:49 ` [PATCH v6 " Chris Metcalf 2013-08-09 17:49 ` Chris Metcalf 2013-08-09 17:52 ` [PATCH v6 2/2] mm: make lru_add_drain_all() selective Chris Metcalf 2013-08-09 17:52 ` Chris Metcalf 2013-08-07 20:52 ` [PATCH v5 " Chris Metcalf 2013-08-07 20:52 ` Chris Metcalf 2013-08-07 20:52 ` [PATCH v4 " Chris Metcalf 2013-08-07 20:52 ` Chris Metcalf 2013-08-12 21:05 ` Andrew Morton 2013-08-12 21:05 ` Andrew Morton 2013-08-13 1:53 ` Chris Metcalf 2013-08-13 1:53 ` Chris Metcalf 2013-08-13 19:35 ` Andrew Morton 2013-08-13 19:35 ` Andrew Morton 2013-08-13 20:19 ` Tejun Heo 2013-08-13 20:19 ` Tejun Heo 2013-08-13 20:31 ` Andrew Morton 2013-08-13 20:31 ` Andrew Morton 2013-08-13 20:59 ` Chris Metcalf 2013-08-13 20:59 ` Chris Metcalf 2013-08-13 21:13 ` Andrew Morton 2013-08-13 21:13 ` Andrew Morton 2013-08-13 22:13 ` Chris Metcalf 2013-08-13 22:13 ` Chris Metcalf 2013-08-13 22:26 ` Andrew Morton 2013-08-13 22:26 ` Andrew Morton 2013-08-13 23:04 ` Chris Metcalf 2013-08-13 23:04 ` Chris Metcalf 2013-08-13 22:51 ` [PATCH v7 1/2] workqueue: add schedule_on_each_cpu_cond Chris Metcalf 2013-08-13 22:51 ` Chris Metcalf 2013-08-13 22:53 ` [PATCH v7 2/2] mm: make lru_add_drain_all() selective Chris Metcalf 2013-08-13 22:53 ` Chris Metcalf 2013-08-13 23:29 ` Tejun Heo 2013-08-13 23:29 ` Tejun Heo 2013-08-13 23:32 ` Chris Metcalf 2013-08-13 23:32 ` Chris Metcalf 2013-08-14 6:46 ` Andrew Morton 2013-08-14 6:46 ` Andrew Morton 2013-08-14 13:05 ` Tejun Heo 2013-08-14 13:05 ` Tejun Heo 2013-08-14 16:03 ` Chris Metcalf 2013-08-14 16:03 ` Chris Metcalf 2013-08-14 16:57 ` Tejun Heo 2013-08-14 16:57 ` Tejun Heo 2013-08-14 17:18 ` Chris Metcalf 2013-08-14 17:18 ` Chris Metcalf 2013-08-14 20:07 ` Tejun Heo 2013-08-14 20:07 ` Tejun Heo 2013-08-14 20:22 ` [PATCH v8] " Chris Metcalf 2013-08-14 20:22 ` Chris Metcalf 2013-08-14 20:44 ` Andrew Morton 2013-08-14 20:44 ` Andrew Morton 2013-08-14 20:50 ` Tejun Heo 2013-08-14 20:50 ` Tejun Heo 2013-08-14 21:03 ` Andrew Morton 2013-08-14 21:03 ` Andrew Morton 2013-08-14 21:07 ` Andrew Morton 2013-08-14 21:07 ` Andrew Morton 2013-08-14 21:12 ` Andrew Morton 2013-08-14 21:12 ` Andrew Morton 2013-08-14 21:23 ` Chris Metcalf 2013-08-14 21:23 ` Chris Metcalf 2013-08-13 23:44 ` [PATCH v7 2/2] " Chris Metcalf 2013-08-13 23:44 ` Chris Metcalf 2013-08-13 23:51 ` Tejun Heo 2013-08-13 23:51 ` Tejun Heo 2013-08-13 21:07 ` [PATCH v4 " Tejun Heo 2013-08-13 21:07 ` Tejun Heo 2013-08-13 21:16 ` Andrew Morton 2013-08-13 21:16 ` Andrew Morton 2013-08-13 22:07 ` Tejun Heo 2013-08-13 22:07 ` Tejun Heo 2013-08-13 22:18 ` Andrew Morton 2013-08-13 22:18 ` Andrew Morton 2013-08-13 22:33 ` Tejun Heo 2013-08-13 22:33 ` Tejun Heo 2013-08-13 22:47 ` Andrew Morton 2013-08-13 22:47 ` Andrew Morton 2013-08-13 23:03 ` Tejun Heo [this message] 2013-08-13 23:03 ` Tejun Heo
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