|From:||Michael Kerrisk <mtk.manpages-AT-gmail.com>|
|To:||Minchan Kim <minchan-AT-kernel.org>|
|Subject:||Re: [RFC 1/4] mm: Per process reclaim|
|Date:||Wed, 3 Apr 2013 12:10:22 +0200|
|Cc:||Andrew Morton <akpm-AT-linux-foundation.org>, Linux Kernel <linux-kernel-AT-vger.kernel.org>, linux-mm <linux-mm-AT-kvack.org>, Mel Gorman <mgorman-AT-suse.de>, Rik van Riel <riel-AT-redhat.com>, Johannes Weiner <hannes-AT-cmpxchg.org>, Hugh Dickins <hughd-AT-google.com>, Sangseok Lee <sangseok.lee-AT-lge.com>, Michael Kerrisk-manpages <mtk.manpages-AT-gmail.com>|
Hello Minchan, On Mon, Mar 25, 2013 at 7:21 AM, Minchan Kim <firstname.lastname@example.org> 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/<pid>/" 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. This interface seems to work as advertized, at least from some light testing that I've done. However, the interface is a quite blunt instrument. Would there be any virtue in extending it so that an address range could be written to /proc/PID/reclaim? Used in conjunction with /proc/PID/maps, a manager process might then choose to trigger reclaim of just selected regions of a processes address space. Thus, one might reclaim file backed pages in a range using: echo '2 start-address end-address' > /proc/PID/reclaim What do you think? Thanks, Michael -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to email@example.com More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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