From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 11 Dec 2007 12:03:49 +0900 From: KAMEZAWA Hiroyuki Subject: [DOC][for -mm] update Documentation/controller/memory.txt Message-Id: <20071211120349.3ae9c55c.kamezawa.hiroyu@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: "balbir@linux.vnet.ibm.com" , "riel@redhat.com" , "yamamoto@valinux.co.jp" , LKML , "linux-mm@kvack.org" List-ID: Balbir-san, could you review this update ? -- Documentation updates for memory controller. Signed-off-by: KAMEZAWA Hiroyuki Index: linux-2.6.24-rc4-mm1/Documentation/controllers/memory.txt =================================================================== --- linux-2.6.24-rc4-mm1.orig/Documentation/controllers/memory.txt +++ linux-2.6.24-rc4-mm1/Documentation/controllers/memory.txt @@ -9,8 +9,7 @@ d. Provides a double LRU: global memory global LRU; a cgroup on hitting a limit, reclaims from the per cgroup LRU -NOTE: Page Cache (unmapped) also includes Swap Cache pages as a subset -and will not be referred to explicitly in the rest of the documentation. +NOTE: Swap Cache (unmapped) is not accounted now. Benefits and Purpose of the memory controller @@ -144,7 +143,7 @@ list. The memory controller uses the following hierarchy 1. zone->lru_lock is used for selecting pages to be isolated -2. mem->lru_lock protects the per cgroup LRU +2. mem->per_zone->lru_lock protects the per cgroup LRU (per zone) 3. lock_page_cgroup() is used to protect page->page_cgroup 3. User Interface @@ -193,6 +192,15 @@ this file after a write to guarantee the The memory.failcnt field gives the number of times that the cgroup limit was exceeded. +The memory.stat file gives accounting information. Now, the number of +caches, RSS and Active pages/Inactive pages are shown. + +The memory.force_empty gives an interface to drop *all* charges by force. + +# echo -n 1 > memory.force_empty + +will drop all charges in cgroup. Currently, this is maintained for test. + 4. Testing Balbir posted lmbench, AIM9, LTP and vmmstress results [10] and [11]. @@ -222,11 +230,8 @@ reclaimed. A cgroup can be removed by rmdir, but as discussed in sections 4.1 and 4.2, a cgroup might have some charge associated with it, even though all -tasks have migrated away from it. If some pages are still left, after following -the steps listed in sections 4.1 and 4.2, check the Swap Cache usage in -/proc/meminfo to see if the Swap Cache usage is showing up in the -cgroups memory.usage_in_bytes counter. A simple test of swapoff -a and -swapon -a should free any pending Swap Cache usage. +tasks have migrated away from it. Such charges are automatically dropped at +rmdir() if there are no tasks. 4.4 Choosing what to account -- Page Cache (unmapped) vs RSS (mapped)? @@ -238,15 +243,11 @@ echo -n 1 > memory.control_type 5. TODO 1. Add support for accounting huge pages (as a separate controller) -2. Improve the user interface to accept/display memory limits in KB or MB - rather than pages (since page sizes can differ across platforms/machines). -3. Make cgroup lists per-zone -4. Make per-cgroup scanner reclaim not-shared pages first -5. Teach controller to account for shared-pages -6. Start reclamation when the limit is lowered -7. Start reclamation in the background when the limit is +2. Make per-cgroup scanner reclaim not-shared pages first +3. Teach controller to account for shared-pages +4. Start reclamation when the limit is lowered +5. Start reclamation in the background when the limit is not yet hit but the usage is getting closer -8. Create per zone LRU lists per cgroup Summary -- 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