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author | San Mehat <san@google.com> | 2010-05-05 11:38:42 -0700 |
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committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-11-30 20:51:37 +0900 |
commit | 4755b72e261478b48337e0e54c8448cbea32c5c8 (patch) | |
tree | 4472d4b014a9a74486882746dafbe3e59c20def1 /drivers/staging | |
parent | 4964cd41cd966502c1e0c5bc929ed15c175f8218 (diff) | |
download | op-kernel-dev-4755b72e261478b48337e0e54c8448cbea32c5c8.zip op-kernel-dev-4755b72e261478b48337e0e54c8448cbea32c5c8.tar.gz |
staging: android: lowmemkiller: Substantially reduce overhead during reclaim
This patch optimizes lowmemkiller to not do any work when it has an outstanding
kill-request. This greatly reduces the pressure on the task_list lock
(improving interactivity), as well as improving the vmscan performance
when under heavy memory pressure (by up to 20x in tests).
Note: For this enhancement to work, you need CONFIG_PROFILING
Signed-off-by: San Mehat <san@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/staging')
-rw-r--r-- | drivers/staging/android/lowmemorykiller.c | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/drivers/staging/android/lowmemorykiller.c b/drivers/staging/android/lowmemorykiller.c index 8372178..4523093 100644 --- a/drivers/staging/android/lowmemorykiller.c +++ b/drivers/staging/android/lowmemorykiller.c @@ -34,6 +34,8 @@ #include <linux/mm.h> #include <linux/oom.h> #include <linux/sched.h> +#include <linux/profile.h> +#include <linux/notifier.h> static uint32_t lowmem_debug_level = 2; static int lowmem_adj[6] = { @@ -51,12 +53,32 @@ static size_t lowmem_minfree[6] = { }; static int lowmem_minfree_size = 4; +static struct task_struct *lowmem_deathpending; + #define lowmem_print(level, x...) \ do { \ if (lowmem_debug_level >= (level)) \ printk(x); \ } while (0) +static int +task_notify_func(struct notifier_block *self, unsigned long val, void *data); + +static struct notifier_block task_nb = { + .notifier_call = task_notify_func, +}; + +static int +task_notify_func(struct notifier_block *self, unsigned long val, void *data) +{ + struct task_struct *task = data; + if (task == lowmem_deathpending) { + lowmem_deathpending = NULL; + task_handoff_unregister(&task_nb); + } + return NOTIFY_OK; +} + static int lowmem_shrink(int nr_to_scan, gfp_t gfp_mask) { struct task_struct *p; @@ -71,6 +93,18 @@ static int lowmem_shrink(int nr_to_scan, gfp_t gfp_mask) int other_free = global_page_state(NR_FREE_PAGES); int other_file = global_page_state(NR_FILE_PAGES); + /* + * If we already have a death outstanding, then + * bail out right away; indicating to vmscan + * that we have nothing further to offer on + * this pass. + * + * Note: Currently you need CONFIG_PROFILING + * for this to work correctly. + */ + if (lowmem_deathpending) + return 0; + if (lowmem_adj_size < array_size) array_size = lowmem_adj_size; if (lowmem_minfree_size < array_size) @@ -142,6 +176,15 @@ static int lowmem_shrink(int nr_to_scan, gfp_t gfp_mask) lowmem_print(1, "send sigkill to %d (%s), adj %d, size %d\n", selected->pid, selected->comm, selected_oom_adj, selected_tasksize); + /* + * If CONFIG_PROFILING is off, then task_handoff_register() + * is a nop. In that case we don't want to stall the killer + * by setting lowmem_deathpending. + */ +#ifdef CONFIG_PROFILING + lowmem_deathpending = selected; + task_handoff_register(&task_nb); +#endif force_sig(SIGKILL, selected); rem -= selected_tasksize; } |