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| -rw-r--r-- | Documentation/controllers/memory.txt | 33 |
1 files changed, 17 insertions, 16 deletions
diff --git a/Documentation/controllers/memory.txt b/Documentation/controllers/memory.txt index 61df8f81c803..b5bbea92a61a 100644 --- a/Documentation/controllers/memory.txt +++ b/Documentation/controllers/memory.txt @@ -9,8 +9,7 @@ d. Provides a double LRU: global memory pressure causes reclaim from the 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 value committed by the kernel. 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 |