Eric Lee / smarc-ti-linux-kernel

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Commit a42c390cfa0c2612459d7226ba11612847ca3a64

Authored by Michal Hocko
Committed by Linus Torvalds
1 parent b1dd693e5b
Exists in master and in 20 other branches dlt-processor-sdk-linux-03.00.00.04, newt-ti-linux-3.12.y, processor-sdk-linux-01.00.00, processor-sdk-linux-02.00.01, smarc-ti-linux-3.12.10, smarc-ti-linux-3.12.y, smarc-ti-linux-3.14.y, smarc-ti-linux-3.15.y, smarc-ti-lsk-linux-4.1.y, smarct3x-processor-sdk-04.01.00.06, smarct3x-processor-sdk-linux-02.00.01, smarct3x-processor-sdk-linux-03.00.00.04, smarct4x-800-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-04.01.00.06, smarct4x-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-linux-03.00.00.04, ti-linux-3.12.y, ti-linux-3.14.y, ti-linux-3.15.y, ti-lsk-linux-4.1.y

cgroups: make swap accounting default behavior configurable 

Swap accounting can be configured by CONFIG_CGROUP_MEM_RES_CTLR_SWAP
configuration option and then it is turned on by default.  There is a boot
option (noswapaccount) which can disable this feature.

This makes it hard for distributors to enable the configuration option as
this feature leads to a bigger memory consumption and this is a no-go for
general purpose distribution kernel.  On the other hand swap accounting
may be very usuful for some workloads.

This patch adds a new configuration option which controls the default
behavior (CGROUP_MEM_RES_CTLR_SWAP_ENABLED).  If the option is selected
then the feature is turned on by default.

It also adds a new boot parameter swapaccount[=1|0] which enhances the
original noswapaccount parameter semantic by means of enable/disable logic
(defaults to 1 if no value is provided to be still consistent with
noswapaccount).

The default behavior is unchanged (if CONFIG_CGROUP_MEM_RES_CTLR_SWAP is
enabled then CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED is enabled as well)

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Showing 3 changed files with 37 additions and 2 deletions Side-by-side Diff

Documentation/kernel-parameters.txt
Diff comments   View file @ a42c390
... ... @@ -2385,6 +2385,11 @@
2385 2385 improve throughput, but will also increase the
2386 2386 amount of memory reserved for use by the client.
2387 2387  
  2388 + swapaccount[=0|1]
  2389 + [KNL] Enable accounting of swap in memory resource
  2390 + controller if no parameter or 1 is given or disable
  2391 + it if 0 is given (See Documentation/cgroups/memory.txt)
  2392 +
2388 2393 swiotlb= [IA-64] Number of I/O TLB slabs
2389 2394  
2390 2395 switches= [HW,M68k]
... ... @@ -613,6 +613,19 @@
613 613 if boot option "noswapaccount" is set, swap will not be accounted.
614 614 Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
615 615 size is 4096bytes, 512k per 1Gbytes of swap.
  616 +config CGROUP_MEM_RES_CTLR_SWAP_ENABLED
  617 + bool "Memory Resource Controller Swap Extension enabled by default"
  618 + depends on CGROUP_MEM_RES_CTLR_SWAP
  619 + default y
  620 + help
  621 + Memory Resource Controller Swap Extension comes with its price in
  622 + a bigger memory consumption. General purpose distribution kernels
  623 + which want to enable the feautre but keep it disabled by default
  624 + and let the user enable it by swapaccount boot command line
  625 + parameter should have this option unselected.
  626 + For those who want to have the feature enabled by default should
  627 + select this option (if, for some reason, they need to disable it
  628 + then noswapaccount does the trick).
616 629  
617 630 menuconfig CGROUP_SCHED
618 631 bool "Group CPU scheduler"
... ... @@ -61,8 +61,15 @@
61 61 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
62 62 /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
63 63 int do_swap_account __read_mostly;
64   -static int really_do_swap_account __initdata = 1; /* for remember boot option*/
  64 +
  65 +/* for remember boot option*/
  66 +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED
  67 +static int really_do_swap_account __initdata = 1;
65 68 #else
  69 +static int really_do_swap_account __initdata = 0;
  70 +#endif
  71 +
  72 +#else
66 73 #define do_swap_account (0)
67 74 #endif
68 75  
69 76  
... ... @@ -4920,10 +4927,20 @@
4920 4927 };
4921 4928  
4922 4929 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
  4930 +static int __init enable_swap_account(char *s)
  4931 +{
  4932 + /* consider enabled if no parameter or 1 is given */
  4933 + if (!s || !strcmp(s, "1"))
  4934 + really_do_swap_account = 1;
  4935 + else if (!strcmp(s, "0"))
  4936 + really_do_swap_account = 0;
  4937 + return 1;
  4938 +}
  4939 +__setup("swapaccount", enable_swap_account);
4923 4940  
4924 4941 static int __init disable_swap_account(char *s)
4925 4942 {
4926   - really_do_swap_account = 0;
  4943 + enable_swap_account("0");
4927 4944 return 1;
4928 4945 }
4929 4946 __setup("noswapaccount", disable_swap_account);