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authorSeongJae Park <sj@kernel.org>2022-03-22 14:49:27 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-03-22 15:57:13 -0700
commitc951cd3b89010c7a4751b9d4ea074007e44851e6 (patch)
treef8d4248af8c1380f677a033ba8f977754a0e3768 /mm/damon/Makefile
parent5257f36ec289d544532f2889cbed11abbb06cf0c (diff)
mm/damon: implement a minimal stub for sysfs-based DAMON interface
DAMON's debugfs-based user interface served very well, so far. However, it unnecessarily depends on debugfs, while DAMON is not aimed to be used for only debugging. Also, the interface receives multiple values via one file. For example, schemes file receives 18 values separated by white spaces. As a result, it is ineffient, hard to be used, and difficult to be extended. Especially, keeping backward compatibility of user space tools is getting only challenging. It would be better to implement another reliable and flexible interface and deprecate the debugfs interface in long term. To this end, this commit implements a stub of a part of the new user interface of DAMON using sysfs. Specifically, this commit implements the sysfs control parts for virtual address space monitoring. More specifically, the idea of the new interface is, using directory hierarchies and making one file for one value. The hierarchy that this commit is introducing is as below. In the below figure, parents-children relations are represented with indentations, each directory is having ``/`` suffix, and files in each directory are separated by comma (","). /sys/kernel/mm/damon/admin │ kdamonds/nr_kdamonds │ │ 0/state,pid │ │ │ contexts/nr_contexts │ │ │ │ 0/operations │ │ │ │ │ monitoring_attrs/ │ │ │ │ │ │ intervals/sample_us,aggr_us,update_us │ │ │ │ │ │ nr_regions/min,max │ │ │ │ │ targets/nr_targets │ │ │ │ │ │ 0/pid_target │ │ │ │ │ │ ... │ │ │ │ ... │ │ ... Writing a number <N> to each 'nr' file makes directories of name <0> to <N-1> in the directory of the 'nr' file. That's all this commit does. Writing proper values to relevant files will construct the DAMON contexts, and writing a special keyword, 'on', to 'state' files for each kdamond will ask DAMON to start the constructed contexts. For a short example, using below commands for monitoring virtual address spaces of a given workload is imaginable: # cd /sys/kernel/mm/damon/admin/ # echo 1 > kdamonds/nr_kdamonds # echo 1 > kdamonds/0/contexts/nr_contexts # echo vaddr > kdamonds/0/contexts/0/operations # echo 1 > kdamonds/0/contexts/0/targets/nr_targets # echo $(pidof <workload>) > kdamonds/0/contexts/0/targets/0/pid_target # echo on > kdamonds/0/state Please note that this commit is implementing only the sysfs part stub as abovely mentioned. This commit doesn't implement the special keywords for 'state' files. Following commits will do that. [jiapeng.chong@linux.alibaba.com: fix missing error code in damon_sysfs_attrs_add_dirs()] Link: https://lkml.kernel.org/r/20220302111120.24984-1-jiapeng.chong@linux.alibaba.com Link: https://lkml.kernel.org/r/20220228081314.5770-4-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com> Cc: David Rientjes <rientjes@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Xin Hao <xhao@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/damon/Makefile')
-rw-r--r--mm/damon/Makefile1
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/damon/Makefile b/mm/damon/Makefile
index aebbf6c14c51..dbf7190b4144 100644
--- a/mm/damon/Makefile
+++ b/mm/damon/Makefile
@@ -3,5 +3,6 @@
obj-y := core.o
obj-$(CONFIG_DAMON_VADDR) += ops-common.o vaddr.o
obj-$(CONFIG_DAMON_PADDR) += ops-common.o paddr.o
+obj-$(CONFIG_DAMON_SYSFS) += sysfs.o
obj-$(CONFIG_DAMON_DBGFS) += dbgfs.o
obj-$(CONFIG_DAMON_RECLAIM) += reclaim.o