kernfs_memcg: Add helpers to gather memcgroup related data #96
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I have added other helpers and modified the earlier ones, so that they work with other UEK versions as well |
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drgn_tools/kernfs_memcg.py
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| """ | ||
| Dump hierarchy of active mem cgroups. | ||
| """ | ||
| cgroup_subsys = prog["cgroup_subsys"][4] |
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Can you add a comment why it's 4 here, what is the kernel definition?
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4 is cgroup subsystem id for memory cgroups. I have replaced it with a const, explaining what is represents
drgn_tools/kernfs_memcg.py
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| print(f"dumping: {cgroup_subsys.name.string_().decode()} hierarchy") | ||
| for pos in css_for_each_descendant_pre(css): | ||
| print( | ||
| f"path: {cgroup_path(pos.cgroup).decode()} flags: 0x{pos.flags.value_():x}" |
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Can we make flags human readable? For example, mention zombie cgroup not 0x0.
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Done. Now the dump looks like the snippet shown below:
`age: 0xffffc35c99dbb040 cgroup: /user.slice/user-0.slice/session-7128.scope state: CSS_ONLINE|CSS_VISIBLE path: oracle_230124_0745EST/diag/asm/cell/scaqat06celadm02/incpkg/pkg_121/seq_1/cell/cellcli.lst.root.0
page: 0xffffc35c99dbb080 cgroup: /user.slice/user-0.slice/session-7128.scope state: CSS_ONLINE|CSS_VISIBLE path: oracle_230124_0745EST/diag/asm/cell/scaqat06celadm02/incpkg/pkg_121/seq_1/cell/cellsrv_pid.lst
page: 0xffffc35c99dbb0c0 cgroup: /user.slice/user-0.slice/session-7128.scope state: CSS_ONLINE|CSS_VISIBLE path: oracle_230124_0745EST/diag/asm/cell/scaqat06celadm02/incpkg/pkg_121/seq_1/cell/cellsrv_pid.lst
page: 0xffffc35c99dbb100 cgroup: /user.slice/user-0.slice/session-7128.scope state: CSS_ONLINE|CSS_VISIBLE path: oracle_230124_0745EST/diag/asm/cell/scaqat06celadm02/incpkg/pkg_121/seq_1/cell/cellsrv_pid.lst
.........................................................................
page: 0xffffc35c99dbb140 cgroup: /user.slice/user-0.slice/session-7126.scope state: ZOMBIE path: oracle_230124_0745EST/diag/asm/cell/scaqat06celadm02/incpkg/pkg_121/seq_1/cell/cellsrv_pid.lst
`
Please let me know if it looks okay now
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The "state" looks good, but the file path doesn't look like a full path, it looks like a relative path to some mounted volume, please fix it.
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I have fixed path info. It turns out neither dentry_path nor inode_path give the full path (including the mount point). drgn_tools.dentry.dentry_path_any_mount gives the full path
drgn_tools/kernfs_memcg.py
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| continue | ||
| dentry = Object(prog, "struct dentry", address=dentry_addr) | ||
| print( | ||
| f"page: 0x{page.value_():x} cgroup: {cgroup_path(cgrp).decode()} flags: {cgrp.self.flags.value_()} dpath: {dentry_path(dentry.address_of_()).decode()}\n" |
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sound like inode_path drgn helper can get the path from inode, with that, you can remove the logic to locate dentry.
Again please make that flags human readable
Signed-off-by: Imran Khan <[email protected]>
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Thanks @biger410 for reviewing this. I have addressed your review comments. Could you please have a look and let me know if you have any further feedback |
Add kernfs based helpers to extract memcg related information, like number of active and inactive memcgroups, page cache pages pinning memcgroups etc. Orabug: 37322867 Signed-off-by: Imran Khan <[email protected]>
Orabug: 37322867 Signed-off-by: Imran Khan <[email protected]>
Orabug: 37322867 Signed-off-by: Imran Khan <[email protected]>
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The new changes look good to me. One more request is that can we add a corelen module for it? It should run either with -M option or -A option. |
This as of now is just a dump of some of my bespoke debug scripts.