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 v8] mm: make lru_add_drain_all() selective Date: Wed, 14 Aug 2013 16:50:29 -0400 [thread overview] Message-ID: <20130814205029.GN28628@htj.dyndns.org> (raw) In-Reply-To: <20130814134430.50cb8d609643620b00ab3705@linux-foundation.org> Hello, On Wed, Aug 14, 2013 at 01:44:30PM -0700, Andrew Morton wrote: > > +static bool need_activate_page_drain(int cpu) > > +{ > > + return pagevec_count(&per_cpu(activate_page_pvecs, cpu)) != 0; > > +} > > static int need_activate_page_drain(int cpu) > { > return pagevec_count(&per_cpu(activate_page_pvecs, cpu)); > } > > would be shorter and faster. bool rather sucks that way. It's a > performance-vs-niceness thing. I guess one has to look at the call > frequency when deciding. "!= 0" can be dropped but I'm fairly sure the compiler would be able to figure out that the type conversion can be skipped. It's a trivial optimization. > > + schedule_work_on(cpu, work); > > + cpumask_set_cpu(cpu, &has_work); > > + } > > + } > > + > > + for_each_cpu(cpu, &has_work) > > for_each_online_cpu()? That would lead to flushing work items which aren't used and may not have been initialized yet, no? > > + flush_work(&per_cpu(lru_add_drain_work, cpu)); > > + > > + put_online_cpus(); > > + mutex_unlock(&lock); > > } > 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 v8] mm: make lru_add_drain_all() selective Date: Wed, 14 Aug 2013 16:50:29 -0400 [thread overview] Message-ID: <20130814205029.GN28628@htj.dyndns.org> (raw) In-Reply-To: <20130814134430.50cb8d609643620b00ab3705@linux-foundation.org> Hello, On Wed, Aug 14, 2013 at 01:44:30PM -0700, Andrew Morton wrote: > > +static bool need_activate_page_drain(int cpu) > > +{ > > + return pagevec_count(&per_cpu(activate_page_pvecs, cpu)) != 0; > > +} > > static int need_activate_page_drain(int cpu) > { > return pagevec_count(&per_cpu(activate_page_pvecs, cpu)); > } > > would be shorter and faster. bool rather sucks that way. It's a > performance-vs-niceness thing. I guess one has to look at the call > frequency when deciding. "!= 0" can be dropped but I'm fairly sure the compiler would be able to figure out that the type conversion can be skipped. It's a trivial optimization. > > + schedule_work_on(cpu, work); > > + cpumask_set_cpu(cpu, &has_work); > > + } > > + } > > + > > + for_each_cpu(cpu, &has_work) > > for_each_online_cpu()? That would lead to flushing work items which aren't used and may not have been initialized yet, no? > > + flush_work(&per_cpu(lru_add_drain_work, cpu)); > > + > > + put_online_cpus(); > > + mutex_unlock(&lock); > > } > 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:[~2013-08-14 20:50 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 [this message] 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 2013-08-13 23:03 ` Tejun Heo
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