linux-kernel - [PATCH -mm v9 8/8] proc: add cond_resched to /proc/kpage* read/write loop

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Date:	Sun, 19 Jul 2015 15:31:17 +0300
From:	Vladimir Davydov <vdavydov@...allels.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
CC:	Andres Lagar-Cavilla <andreslc@...gle.com>,
	Minchan Kim <minchan@...nel.org>,
	Raghavendra K T <raghavendra.kt@...ux.vnet.ibm.com>,
	Johannes Weiner <hannes@...xchg.org>,
	Michal Hocko <mhocko@...e.cz>,
	Greg Thelen <gthelen@...gle.com>,
	Michel Lespinasse <walken@...gle.com>,
	David Rientjes <rientjes@...gle.com>,
	Pavel Emelyanov <xemul@...allels.com>,
	Cyrill Gorcunov <gorcunov@...nvz.org>,
	Jonathan Corbet <corbet@....net>, <linux-api@...r.kernel.org>,
	<linux-doc@...r.kernel.org>, <linux-mm@...ck.org>,
	<cgroups@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH -mm v9 8/8] proc: add cond_resched to /proc/kpage* read/write loop

Reading/writing a /proc/kpage* file may take long on machines with a lot
of RAM installed.

Suggested-by: Andres Lagar-Cavilla <andreslc@...gle.com>
Signed-off-by: Vladimir Davydov <vdavydov@...allels.com>
---
 fs/proc/page.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/fs/proc/page.c b/fs/proc/page.c
index 13dcb823fe4e..7ff7cba8617b 100644
--- a/fs/proc/page.c
+++ b/fs/proc/page.c
@@ -58,6 +58,8 @@ static ssize_t kpagecount_read(struct file *file, char __user *buf,
 		pfn++;
 		out++;
 		count -= KPMSIZE;
+
+		cond_resched();
 	}
 
 	*ppos += (char __user *)out - buf;
@@ -219,6 +221,8 @@ static ssize_t kpageflags_read(struct file *file, char __user *buf,
 		pfn++;
 		out++;
 		count -= KPMSIZE;
+
+		cond_resched();
 	}
 
 	*ppos += (char __user *)out - buf;
@@ -267,6 +271,8 @@ static ssize_t kpagecgroup_read(struct file *file, char __user *buf,
 		pfn++;
 		out++;
 		count -= KPMSIZE;
+
+		cond_resched();
 	}
 
 	*ppos += (char __user *)out - buf;
@@ -421,6 +427,7 @@ static ssize_t kpageidle_read(struct file *file, char __user *buf,
 			idle_bitmap = 0;
 			out++;
 		}
+		cond_resched();
 	}
 
 	*ppos += (char __user *)out - buf;
@@ -467,6 +474,7 @@ static ssize_t kpageidle_write(struct file *file, const char __user *buf,
 				put_page(page);
 			}
 		}
+		cond_resched();
 	}
 
 	*ppos += (const char __user *)in - buf;
-- 
2.1.4

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