From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx170.postini.com [74.125.245.170]) by kanga.kvack.org (Postfix) with SMTP id AC7946B00D4 for ; Wed, 3 Apr 2013 05:18:20 -0400 (EDT) Received: by mail-we0-f175.google.com with SMTP id t11so1005207wey.6 for ; Wed, 03 Apr 2013 02:18:18 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <1364192494-22185-1-git-send-email-minchan@kernel.org> References: <1364192494-22185-1-git-send-email-minchan@kernel.org> From: Michael Kerrisk Date: Wed, 3 Apr 2013 11:17:58 +0200 Message-ID: Subject: Re: [RFC 1/4] mm: Per process reclaim Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: Andrew Morton , Linux Kernel , linux-mm , Mel Gorman , Rik van Riel , Johannes Weiner , Hugh Dickins , Sangseok Lee Hello Minchan, On Mon, Mar 25, 2013 at 7:21 AM, Minchan Kim wrote: > These day, there are many platforms avaiable in the embedded market > and they are smarter than kernel which has very limited information > about working set so they want to involve memory management more heavily > like android's lowmemory killer and ashmem or recent many lowmemory > notifier(there was several trial for various company NOKIA, SAMSUNG, > Linaro, Google ChromeOS, Redhat). > > One of the simple imagine scenario about userspace's intelligence is that > platform can manage tasks as forground and backgroud so it would be > better to reclaim background's task pages for end-user's *responsibility* > although it has frequent referenced pages. > > This patch adds new knob "reclaim under proc//" so task manager > can reclaim any target process anytime, anywhere. It could give another > method to platform for using memory efficiently. > > It can avoid process killing for getting free memory, which was really > terrible experience because I lost my best score of game I had ever > after I switch the phone call while I enjoyed the game. > > Writing 1 to /proc/pid/reclaim reclaims only file pages. > Writing 2 to /proc/pid/reclaim reclaims only anonymous pages. > Writing 3 to /proc/pid/reclaim reclaims all pages from target process. > > Signed-off-by: Minchan Kim > --- > fs/proc/base.c | 3 ++ > fs/proc/internal.h | 1 + > fs/proc/task_mmu.c | 115 +++++++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/rmap.h | 4 ++ > mm/Kconfig | 13 ++++++ > mm/internal.h | 7 +--- > mm/vmscan.c | 59 ++++++++++++++++++++++++++ > 7 files changed, 196 insertions(+), 6 deletions(-) > > diff --git a/fs/proc/base.c b/fs/proc/base.c > index 9b43ff77..ed83e85 100644 [...] > +#define RECLAIM_FILE (1 << 0) > +#define RECLAIM_ANON (1 << 1) > +#define RECLAIM_ALL (RECLAIM_FILE | RECLAIM_ANON) > + > +static ssize_t reclaim_write(struct file *file, const char __user *buf, > + size_t count, loff_t *ppos) > +{ > + struct task_struct *task; > + char buffer[PROC_NUMBUF]; > + struct mm_struct *mm; > + struct vm_area_struct *vma; > + int type; > + int rv; > + > + memset(buffer, 0, sizeof(buffer)); > + if (count > sizeof(buffer) - 1) > + count = sizeof(buffer) - 1; > + if (copy_from_user(buffer, buf, count)) > + return -EFAULT; > + rv = kstrtoint(strstrip(buffer), 10, &type); > + if (rv < 0) > + return rv > + if (type < RECLAIM_ALL || type > RECLAIM_FILE) > + return -EINVAL;> + task = get_proc_task(file->f_path.dentry->d_inode); The check here is the wrong way round. Should be if (type < RECLAIM_FILE || type > RECLAIM_ALL) Thanks, Michael -- 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: email@kvack.org