Revision tags: v6.6.35, v6.6.34, v6.6.33 |
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#
99ed145f |
| 28-May-2024 |
Chengming Zhou <chengming.zhou@linux.dev> |
mm/ksm: fix ksm_zero_pages accounting
commit c2dc78b86e0821ecf9a9d0c35dba2618279a5bb6 upstream.
We normally ksm_zero_pages++ in ksmd when page is merged with zero page, but ksm_zero_pages-- is done
mm/ksm: fix ksm_zero_pages accounting
commit c2dc78b86e0821ecf9a9d0c35dba2618279a5bb6 upstream.
We normally ksm_zero_pages++ in ksmd when page is merged with zero page, but ksm_zero_pages-- is done from page tables side, where there is no any accessing protection of ksm_zero_pages.
So we can read very exceptional value of ksm_zero_pages in rare cases, such as -1, which is very confusing to users.
Fix it by changing to use atomic_long_t, and the same case with the mm->ksm_zero_pages.
Link: https://lkml.kernel.org/r/20240528-b4-ksm-counters-v3-2-34bb358fdc13@linux.dev Fixes: e2942062e01d ("ksm: count all zero pages placed by KSM") Fixes: 6080d19f0704 ("ksm: add ksm zero pages for each process") Signed-off-by: Chengming Zhou <chengming.zhou@linux.dev> Acked-by: David Hildenbrand <david@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ran Xiaokai <ran.xiaokai@zte.com.cn> Cc: Stefan Roesch <shr@devkernel.io> Cc: xu xin <xu.xin16@zte.com.cn> Cc: Yang Yang <yang.yang29@zte.com.cn> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Revision tags: v6.6.35, v6.6.34, v6.6.33 |
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#
99ed145f |
| 28-May-2024 |
Chengming Zhou <chengming.zhou@linux.dev> |
mm/ksm: fix ksm_zero_pages accounting
commit c2dc78b86e0821ecf9a9d0c35dba2618279a5bb6 upstream.
We normally ksm_zero_pages++ in ksmd when page is merged with zero page, but ksm_zero_pages-- is done
mm/ksm: fix ksm_zero_pages accounting
commit c2dc78b86e0821ecf9a9d0c35dba2618279a5bb6 upstream.
We normally ksm_zero_pages++ in ksmd when page is merged with zero page, but ksm_zero_pages-- is done from page tables side, where there is no any accessing protection of ksm_zero_pages.
So we can read very exceptional value of ksm_zero_pages in rare cases, such as -1, which is very confusing to users.
Fix it by changing to use atomic_long_t, and the same case with the mm->ksm_zero_pages.
Link: https://lkml.kernel.org/r/20240528-b4-ksm-counters-v3-2-34bb358fdc13@linux.dev Fixes: e2942062e01d ("ksm: count all zero pages placed by KSM") Fixes: 6080d19f0704 ("ksm: add ksm zero pages for each process") Signed-off-by: Chengming Zhou <chengming.zhou@linux.dev> Acked-by: David Hildenbrand <david@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ran Xiaokai <ran.xiaokai@zte.com.cn> Cc: Stefan Roesch <shr@devkernel.io> Cc: xu xin <xu.xin16@zte.com.cn> Cc: Yang Yang <yang.yang29@zte.com.cn> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Revision tags: v6.6.35, v6.6.34, v6.6.33 |
|
#
99ed145f |
| 28-May-2024 |
Chengming Zhou <chengming.zhou@linux.dev> |
mm/ksm: fix ksm_zero_pages accounting
commit c2dc78b86e0821ecf9a9d0c35dba2618279a5bb6 upstream.
We normally ksm_zero_pages++ in ksmd when page is merged with zero page, but ksm_zero_pages-- is done
mm/ksm: fix ksm_zero_pages accounting
commit c2dc78b86e0821ecf9a9d0c35dba2618279a5bb6 upstream.
We normally ksm_zero_pages++ in ksmd when page is merged with zero page, but ksm_zero_pages-- is done from page tables side, where there is no any accessing protection of ksm_zero_pages.
So we can read very exceptional value of ksm_zero_pages in rare cases, such as -1, which is very confusing to users.
Fix it by changing to use atomic_long_t, and the same case with the mm->ksm_zero_pages.
Link: https://lkml.kernel.org/r/20240528-b4-ksm-counters-v3-2-34bb358fdc13@linux.dev Fixes: e2942062e01d ("ksm: count all zero pages placed by KSM") Fixes: 6080d19f0704 ("ksm: add ksm zero pages for each process") Signed-off-by: Chengming Zhou <chengming.zhou@linux.dev> Acked-by: David Hildenbrand <david@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ran Xiaokai <ran.xiaokai@zte.com.cn> Cc: Stefan Roesch <shr@devkernel.io> Cc: xu xin <xu.xin16@zte.com.cn> Cc: Yang Yang <yang.yang29@zte.com.cn> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Revision tags: v6.6.35, v6.6.34, v6.6.33 |
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#
99ed145f |
| 28-May-2024 |
Chengming Zhou <chengming.zhou@linux.dev> |
mm/ksm: fix ksm_zero_pages accounting
commit c2dc78b86e0821ecf9a9d0c35dba2618279a5bb6 upstream.
We normally ksm_zero_pages++ in ksmd when page is merged with zero page, but ksm_zero_pages-- is done
mm/ksm: fix ksm_zero_pages accounting
commit c2dc78b86e0821ecf9a9d0c35dba2618279a5bb6 upstream.
We normally ksm_zero_pages++ in ksmd when page is merged with zero page, but ksm_zero_pages-- is done from page tables side, where there is no any accessing protection of ksm_zero_pages.
So we can read very exceptional value of ksm_zero_pages in rare cases, such as -1, which is very confusing to users.
Fix it by changing to use atomic_long_t, and the same case with the mm->ksm_zero_pages.
Link: https://lkml.kernel.org/r/20240528-b4-ksm-counters-v3-2-34bb358fdc13@linux.dev Fixes: e2942062e01d ("ksm: count all zero pages placed by KSM") Fixes: 6080d19f0704 ("ksm: add ksm zero pages for each process") Signed-off-by: Chengming Zhou <chengming.zhou@linux.dev> Acked-by: David Hildenbrand <david@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ran Xiaokai <ran.xiaokai@zte.com.cn> Cc: Stefan Roesch <shr@devkernel.io> Cc: xu xin <xu.xin16@zte.com.cn> Cc: Yang Yang <yang.yang29@zte.com.cn> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Revision tags: v6.6.35, v6.6.34, v6.6.33 |
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#
99ed145f |
| 28-May-2024 |
Chengming Zhou <chengming.zhou@linux.dev> |
mm/ksm: fix ksm_zero_pages accounting
commit c2dc78b86e0821ecf9a9d0c35dba2618279a5bb6 upstream.
We normally ksm_zero_pages++ in ksmd when page is merged with zero page, but ksm_zero_pages-- is done
mm/ksm: fix ksm_zero_pages accounting
commit c2dc78b86e0821ecf9a9d0c35dba2618279a5bb6 upstream.
We normally ksm_zero_pages++ in ksmd when page is merged with zero page, but ksm_zero_pages-- is done from page tables side, where there is no any accessing protection of ksm_zero_pages.
So we can read very exceptional value of ksm_zero_pages in rare cases, such as -1, which is very confusing to users.
Fix it by changing to use atomic_long_t, and the same case with the mm->ksm_zero_pages.
Link: https://lkml.kernel.org/r/20240528-b4-ksm-counters-v3-2-34bb358fdc13@linux.dev Fixes: e2942062e01d ("ksm: count all zero pages placed by KSM") Fixes: 6080d19f0704 ("ksm: add ksm zero pages for each process") Signed-off-by: Chengming Zhou <chengming.zhou@linux.dev> Acked-by: David Hildenbrand <david@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ran Xiaokai <ran.xiaokai@zte.com.cn> Cc: Stefan Roesch <shr@devkernel.io> Cc: xu xin <xu.xin16@zte.com.cn> Cc: Yang Yang <yang.yang29@zte.com.cn> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Revision tags: v6.6.32, v6.6.31, v6.6.30, v6.6.29, v6.6.28, v6.6.27, v6.6.26, v6.6.25, v6.6.24, v6.6.23, v6.6.16, v6.6.15, v6.6.14, v6.6.13, v6.6.12, v6.6.11, v6.6.10, v6.6.9, v6.6.8, v6.6.7, v6.6.6, v6.6.5, v6.6.4, v6.6.3, v6.6.2, v6.5.11, v6.6.1, v6.5.10, v6.6, v6.5.9, v6.5.8, v6.5.7, v6.5.6, v6.5.5, v6.5.4, v6.5.3, v6.5.2, v6.1.51, v6.5.1, v6.1.50, v6.5, v6.1.49, v6.1.48 |
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#
dce8f8ed |
| 23-Aug-2023 |
Oleg Nesterov <oleg@redhat.com> |
document while_each_thread(), change first_tid() to use for_each_thread()
Add the comment to explain that while_each_thread(g,t) is not rcu-safe unless g is stable (e.g. current). Even if g is a g
document while_each_thread(), change first_tid() to use for_each_thread()
Add the comment to explain that while_each_thread(g,t) is not rcu-safe unless g is stable (e.g. current). Even if g is a group leader and thus can't exit before t, t or another sub-thread can exec and remove g from the thread_group list.
The only lockless user of while_each_thread() is first_tid() and it is fine in that it can't loop forever, yet for_each_thread() looks better and I am going to change while_each_thread/next_thread.
Link: https://lkml.kernel.org/r/20230823170806.GA11724@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Revision tags: v6.1.46, v6.1.45, v6.1.44, v6.1.43, v6.1.42, v6.1.41, v6.1.40, v6.1.39, v6.1.38, v6.1.37, v6.1.36, v6.4, v6.1.35, v6.1.34 |
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#
6080d19f |
| 12-Jun-2023 |
xu xin <xu.xin16@zte.com.cn> |
ksm: add ksm zero pages for each process
As the number of ksm zero pages is not included in ksm_merging_pages per process when enabling use_zero_pages, it's unclear of how many actual pages are merg
ksm: add ksm zero pages for each process
As the number of ksm zero pages is not included in ksm_merging_pages per process when enabling use_zero_pages, it's unclear of how many actual pages are merged by KSM. To let users accurately estimate their memory demands when unsharing KSM zero-pages, it's necessary to show KSM zero- pages per process. In addition, it help users to know the actual KSM profit because KSM-placed zero pages are also benefit from KSM.
since unsharing zero pages placed by KSM accurately is achieved, then tracking empty pages merging and unmerging is not a difficult thing any longer.
Since we already have /proc/<pid>/ksm_stat, just add the information of 'ksm_zero_pages' in it.
Link: https://lkml.kernel.org/r/20230613030938.185993-1-yang.yang29@zte.com.cn Signed-off-by: xu xin <xu.xin16@zte.com.cn> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Xiaokai Ran <ran.xiaokai@zte.com.cn> Reviewed-by: Yang Yang <yang.yang29@zte.com.cn> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: Xuexin Jiang <jiang.xuexin@zte.com.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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0d72b928 |
| 07-Aug-2023 |
Jeff Layton <jlayton@kernel.org> |
fs: pass the request_mask to generic_fillattr
generic_fillattr just fills in the entire stat struct indiscriminately today, copying data from the inode. There is at least one attribute (STATX_CHANGE
fs: pass the request_mask to generic_fillattr
generic_fillattr just fills in the entire stat struct indiscriminately today, copying data from the inode. There is at least one attribute (STATX_CHANGE_COOKIE) that can have side effects when it is reported, and we're looking at adding more with the addition of multigrain timestamps.
Add a request_mask argument to generic_fillattr and have most callers just pass in the value that is passed to getattr. Have other callers (e.g. ksmbd) just pass in STATX_BASIC_STATS. Also move the setting of STATX_CHANGE_COOKIE into generic_fillattr.
Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com> Reviewed-by: Xiubo Li <xiubli@redhat.com> Reviewed-by: "Paulo Alcantara (SUSE)" <pc@manguebit.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jeff Layton <jlayton@kernel.org> Message-Id: <20230807-mgctime-v7-2-d1dec143a704@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
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#
0a2c2baa |
| 05-Aug-2023 |
Linus Torvalds <torvalds@linux-foundation.org> |
proc: fix missing conversion to 'iterate_shared'
I'm looking at the directory handling due to the discussion about f_pos locking (see commit 797964253d35: "file: reinstate f_pos locking optimization
proc: fix missing conversion to 'iterate_shared'
I'm looking at the directory handling due to the discussion about f_pos locking (see commit 797964253d35: "file: reinstate f_pos locking optimization for regular files"), and wanting to clean that up.
And one source of ugliness is how we were supposed to move filesystems over to the '->iterate_shared()' function that only takes the inode lock for reading many many years ago, but several filesystems still use the bad old '->iterate()' that takes the inode lock for exclusive access.
See commit 6192269444eb ("introduce a parallel variant of ->iterate()") that also added some documentation stating
Old method is only used if the new one is absent; eventually it will be removed. Switch while you still can; the old one won't stay.
and that was back in April 2016. Here we are, many years later, and the old version is still clearly sadly alive and well.
Now, some of those old style iterators are probably just because the filesystem may end up having per-inode mutable data that it uses for iterating a directory, but at least one case is just a mistake.
Al switched over most filesystems to use '->iterate_shared()' back when it was introduced. In particular, the /proc filesystem was converted as one of the first ones in commit f50752eaa0b0 ("switch all procfs directories ->iterate_shared()").
But then later one new user of '->iterate()' was then re-introduced by commit 6d9c939dbe4d ("procfs: add smack subdir to attrs").
And that's clearly not what we wanted, since that new case just uses the same 'proc_pident_readdir()' and 'proc_pident_lookup()' helper functions that other /proc pident directories use, and they are most definitely safe to use with the inode lock held shared.
So just fix it.
This still leaves a fair number of oddball filesystems using the old-style directory iterator (ceph, coda, exfat, jfs, ntfs, ocfs2, overlayfs, and vboxsf), but at least we don't have any remaining in the core filesystems.
I'm going to add a wrapper function that just drops the read-lock and takes it as a write lock, so that we can clean up the core vfs layer and make all the ugly 'this filesystem needs exclusive inode locking' be just filesystem-internal warts.
I just didn't want to make that conversion when we still had a core user left.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
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#
e9d7d3cb |
| 05-Jul-2023 |
Jeff Layton <jlayton@kernel.org> |
procfs: convert to ctime accessor functions
In later patches, we're going to change how the inode's ctime field is used. Switch to using accessor functions instead of raw accesses of inode->i_ctime.
procfs: convert to ctime accessor functions
In later patches, we're going to change how the inode's ctime field is used. Switch to using accessor functions instead of raw accesses of inode->i_ctime.
Acked-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Message-Id: <20230705190309.579783-65-jlayton@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
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#
ccf61486 |
| 13-Jul-2023 |
Aleksa Sarai <cyphar@cyphar.com> |
procfs: block chmod on /proc/thread-self/comm
Due to an oversight in commit 1b3044e39a89 ("procfs: fix pthread cross-thread naming if !PR_DUMPABLE") in switching from REG to NOD, chmod operations on
procfs: block chmod on /proc/thread-self/comm
Due to an oversight in commit 1b3044e39a89 ("procfs: fix pthread cross-thread naming if !PR_DUMPABLE") in switching from REG to NOD, chmod operations on /proc/thread-self/comm were no longer blocked as they are on almost all other procfs files.
A very similar situation with /proc/self/environ was used to as a root exploit a long time ago, but procfs has SB_I_NOEXEC so this is simply a correctness issue.
Ref: https://lwn.net/Articles/191954/ Ref: 6d76fa58b050 ("Don't allow chmod() on the /proc/<pid>/ files") Fixes: 1b3044e39a89 ("procfs: fix pthread cross-thread naming if !PR_DUMPABLE") Cc: stable@vger.kernel.org # v4.7+ Signed-off-by: Aleksa Sarai <cyphar@cyphar.com> Message-Id: <20230713141001.27046-1-cyphar@cyphar.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
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Revision tags: v6.1.33, v6.1.32, v6.1.31, v6.1.30, v6.1.29, v6.1.28, v6.1.27, v6.1.26, v6.3, v6.1.25 |
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#
d21077fb |
| 18-Apr-2023 |
Stefan Roesch <shr@devkernel.io> |
mm: add new KSM process and sysfs knobs
This adds the general_profit KSM sysfs knob and the process profit metric knobs to ksm_stat.
1) expose general_profit metric
The documentation mentions a
mm: add new KSM process and sysfs knobs
This adds the general_profit KSM sysfs knob and the process profit metric knobs to ksm_stat.
1) expose general_profit metric
The documentation mentions a general profit metric, however this metric is not calculated. In addition the formula depends on the size of internal structures, which makes it more difficult for an administrator to make the calculation. Adding the metric for a better user experience.
2) document general_profit sysfs knob
3) calculate ksm process profit metric
The ksm documentation mentions the process profit metric and how to calculate it. This adds the calculation of the metric.
4) mm: expose ksm process profit metric in ksm_stat
This exposes the ksm process profit metric in /proc/<pid>/ksm_stat. The documentation mentions the formula for the ksm process profit metric, however it does not calculate it. In addition the formula depends on the size of internal structures. So it makes sense to expose it.
5) document new procfs ksm knobs
Link: https://lkml.kernel.org/r/20230418051342.1919757-3-shr@devkernel.io Signed-off-by: Stefan Roesch <shr@devkernel.io> Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Revision tags: v6.1.24, v6.1.23, v6.1.22, v6.1.21, v6.1.20, v6.1.19, v6.1.18, v6.1.17, v6.1.16, v6.1.15, v6.1.14, v6.1.13, v6.2, v6.1.12, v6.1.11, v6.1.10, v6.1.9 |
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#
b99b2588 |
| 31-Jan-2023 |
Chao Yu <chao@kernel.org> |
proc: remove mark_inode_dirty() in .setattr()
procfs' .setattr() has updated i_uid, i_gid and i_mode into proc dirent, we don't need to call mark_inode_dirty() for delayed update, remove it.
Link:
proc: remove mark_inode_dirty() in .setattr()
procfs' .setattr() has updated i_uid, i_gid and i_mode into proc dirent, we don't need to call mark_inode_dirty() for delayed update, remove it.
Link: https://lkml.kernel.org/r/20230131150840.34726-1-chao@kernel.org Signed-off-by: Chao Yu <chao@kernel.org> Reviewed-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Revision tags: v6.1.8, v6.1.7, v6.1.6 |
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#
4609e1f1 |
| 13-Jan-2023 |
Christian Brauner <brauner@kernel.org> |
fs: port ->permission() to pass mnt_idmap
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is j
fs: port ->permission() to pass mnt_idmap
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
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b74d24f7 |
| 13-Jan-2023 |
Christian Brauner <brauner@kernel.org> |
fs: port ->getattr() to pass mnt_idmap
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just
fs: port ->getattr() to pass mnt_idmap
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
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c1632a0f |
| 13-Jan-2023 |
Christian Brauner <brauner@kernel.org> |
fs: port ->setattr() to pass mnt_idmap
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just
fs: port ->setattr() to pass mnt_idmap
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
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Revision tags: v6.1.5, v6.0.19, v6.0.18, v6.1.4, v6.1.3, v6.0.17, v6.1.2, v6.0.16, v6.1.1, v6.0.15, v6.0.14, v6.0.13, v6.1, v6.0.12, v6.0.11, v6.0.10, v5.15.80, v6.0.9, v5.15.79, v6.0.8, v5.15.78, v6.0.7, v5.15.77, v5.15.76, v6.0.6, v6.0.5, v5.15.75, v6.0.4, v6.0.3, v6.0.2, v5.15.74, v5.15.73, v6.0.1, v5.15.72, v6.0, v5.15.71, v5.15.70, v5.15.69, v5.15.68, v5.15.67, v5.15.66, v5.15.65, v5.15.64 |
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cb4df4ca |
| 30-Aug-2022 |
xu xin <cgel.zte@gmail.com> |
ksm: count allocated ksm rmap_items for each process
Patch series "ksm: count allocated rmap_items and update documentation", v5.
KSM can save memory by merging identical pages, but also can consum
ksm: count allocated ksm rmap_items for each process
Patch series "ksm: count allocated rmap_items and update documentation", v5.
KSM can save memory by merging identical pages, but also can consume additional memory, because it needs to generate rmap_items to save each scanned page's brief rmap information.
To determine how beneficial the ksm-policy (like madvise), they are using brings, so we add a new interface /proc/<pid>/ksm_stat for each process The value "ksm_rmap_items" in it indicates the total allocated ksm rmap_items of this process.
The detailed description can be seen in the following patches' commit message.
This patch (of 2):
KSM can save memory by merging identical pages, but also can consume additional memory, because it needs to generate rmap_items to save each scanned page's brief rmap information. Some of these pages may be merged, but some may not be abled to be merged after being checked several times, which are unprofitable memory consumed.
The information about whether KSM save memory or consume memory in system-wide range can be determined by the comprehensive calculation of pages_sharing, pages_shared, pages_unshared and pages_volatile. A simple approximate calculation:
profit =~ pages_sharing * sizeof(page) - (all_rmap_items) * sizeof(rmap_item);
where all_rmap_items equals to the sum of pages_sharing, pages_shared, pages_unshared and pages_volatile.
But we cannot calculate this kind of ksm profit inner single-process wide because the information of ksm rmap_item's number of a process is lacked. For user applications, if this kind of information could be obtained, it helps upper users know how beneficial the ksm-policy (like madvise) they are using brings, and then optimize their app code. For example, one application madvise 1000 pages as MERGEABLE, while only a few pages are really merged, then it's not cost-efficient.
So we add a new interface /proc/<pid>/ksm_stat for each process in which the value of ksm_rmap_itmes is only shown now and so more values can be added in future.
So similarly, we can calculate the ksm profit approximately for a single process by:
profit =~ ksm_merging_pages * sizeof(page) - ksm_rmap_items * sizeof(rmap_item);
where ksm_merging_pages is shown at /proc/<pid>/ksm_merging_pages, and ksm_rmap_items is shown in /proc/<pid>/ksm_stat.
Link: https://lkml.kernel.org/r/20220830143731.299702-1-xu.xin16@zte.com.cn Link: https://lkml.kernel.org/r/20220830143838.299758-1-xu.xin16@zte.com.cn Signed-off-by: xu xin <xu.xin16@zte.com.cn> Reviewed-by: Xiaokai Ran <ran.xiaokai@zte.com.cn> Reviewed-by: Yang Yang <yang.yang29@zte.com.cn> Signed-off-by: CGEL ZTE <cgel.zte@gmail.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Bagas Sanjaya <bagasdotme@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: Izik Eidus <izik.eidus@ravellosystems.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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5f14b924 |
| 06-Sep-2022 |
Liam R. Howlett <Liam.Howlett@Oracle.com> |
fs/proc/base: use the vma iterators in place of linked list
Use the vma iterator instead of a for loop across the linked list. The link list of vmas will be removed in this patch set.
Link: https:
fs/proc/base: use the vma iterators in place of linked list
Use the vma iterator instead of a for loop across the linked list. The link list of vmas will be removed in this patch set.
Link: https://lkml.kernel.org/r/20220906194824.2110408-43-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Tested-by: Yu Zhao <yuzhao@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: SeongJae Park <sj@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Revision tags: v5.15.63, v5.15.62, v5.15.61, v5.15.60 |
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5b09c9fe |
| 04-Aug-2022 |
Al Viro <viro@zeniv.linux.org.uk> |
do_proc_readlink(): constify path
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Revision tags: v5.15.59, v5.19, v5.15.58, v5.15.57, v5.15.56, v5.15.55, v5.15.54, v5.15.53, v5.15.52, v5.15.51, v5.15.50, v5.15.49, v5.15.48, v5.15.47, v5.15.46, v5.15.45, v5.15.44, v5.15.43, v5.15.42, v5.18, v5.15.41, v5.15.40, v5.15.39, v5.15.38, v5.15.37, v5.15.36, v5.15.35, v5.15.34, v5.15.33, v5.15.32, v5.15.31, v5.17, v5.15.30, v5.15.29, v5.15.28, v5.15.27, v5.15.26, v5.15.25, v5.15.24, v5.15.23, v5.15.22, v5.15.21, v5.15.20, v5.15.19 |
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c8e477c6 |
| 30-Jan-2022 |
Al Viro <viro@zeniv.linux.org.uk> |
->getprocattr(): attribute name is const char *, TYVM...
cast of ->d_name.name to char * is completely wrong - nothing is allowed to modify its contents.
Reviewed-by: Christian Brauner (Microsoft)
->getprocattr(): attribute name is const char *, TYVM...
cast of ->d_name.name to char * is completely wrong - nothing is allowed to modify its contents.
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org> Acked-by: Paul Moore <paul@paul-moore.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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d919a1e7 |
| 13-Jul-2022 |
Zhihao Cheng <chengzhihao1@huawei.com> |
proc: fix a dentry lock race between release_task and lookup
Commit 7bc3e6e55acf06 ("proc: Use a list of inodes to flush from proc") moved proc_flush_task() behind __exit_signal(). Then, process sy
proc: fix a dentry lock race between release_task and lookup
Commit 7bc3e6e55acf06 ("proc: Use a list of inodes to flush from proc") moved proc_flush_task() behind __exit_signal(). Then, process systemd can take long period high cpu usage during releasing task in following concurrent processes:
systemd ps kernel_waitid stat(/proc/tgid) do_wait filename_lookup wait_consider_task lookup_fast release_task __exit_signal __unhash_process detach_pid __change_pid // remove task->pid_links d_revalidate -> pid_revalidate // 0 d_invalidate(/proc/tgid) shrink_dcache_parent(/proc/tgid) d_walk(/proc/tgid) spin_lock_nested(/proc/tgid/fd) // iterating opened fd proc_flush_pid | d_invalidate (/proc/tgid/fd) | shrink_dcache_parent(/proc/tgid/fd) | shrink_dentry_list(subdirs) ↓ shrink_lock_dentry(/proc/tgid/fd) --> race on dentry lock
Function d_invalidate() will remove dentry from hash firstly, but why does proc_flush_pid() process dentry '/proc/tgid/fd' before dentry '/proc/tgid'? That's because proc_pid_make_inode() adds proc inode in reverse order by invoking hlist_add_head_rcu(). But proc should not add any inodes under '/proc/tgid' except '/proc/tgid/task/pid', fix it by adding inode into 'pid->inodes' only if the inode is /proc/tgid or /proc/tgid/task/pid.
Performance regression: Create 200 tasks, each task open one file for 50,000 times. Kill all tasks when opened files exceed 10,000,000 (cat /proc/sys/fs/file-nr).
Before fix: $ time killall -wq aa real 4m40.946s # During this period, we can see 'ps' and 'systemd' taking high cpu usage.
After fix: $ time killall -wq aa real 1m20.732s # During this period, we can see 'systemd' taking high cpu usage.
Link: https://lkml.kernel.org/r/20220713130029.4133533-1-chengzhihao1@huawei.com Fixes: 7bc3e6e55acf06 ("proc: Use a list of inodes to flush from proc") Link: https://bugzilla.kernel.org/show_bug.cgi?id=216054 Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com> Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Suggested-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Baoquan He <bhe@redhat.com> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Yu Kuai <yukuai3@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
76093853 |
| 29-Apr-2022 |
xu xin <xu.xin16@zte.com.cn> |
ksm: count ksm merging pages for each process
Some applications or containers want to use KSM by calling madvise() to advise areas of address space to be MERGEABLE. But they may not know which appl
ksm: count ksm merging pages for each process
Some applications or containers want to use KSM by calling madvise() to advise areas of address space to be MERGEABLE. But they may not know which applications are more likely to cause real merges in the deployment. If this patch is applied, it helps them know their corresponding number of merged pages, and then optimize their app code.
As current KSM only counts the number of KSM merging pages(e.g. ksm_pages_sharing and ksm_pages_shared) of the whole system, we cannot see the more fine-grained KSM merging, for the upper application optimization, the merging area cannot be set easily according to the KSM page merging probability of each process. Therefore, it is necessary to add extra statistical means so that the upper level users can know the detailed KSM merging information of each process.
We add a new proc file named as ksm_merging_pages under /proc/<pid>/ to indicate the involved ksm merging pages of this process.
[akpm@linux-foundation.org: fix comment typo, remove BUG_ON()s] Link: https://lkml.kernel.org/r/20220325082318.2352853-1-xu.xin16@zte.com.cn Signed-off-by: xu xin <xu.xin16@zte.com.cn> Reported-by: kernel test robot <lkp@intel.com> Reviewed-by: Yang Yang <yang.yang29@zte.com.cn> Reviewed-by: Ran Xiaokai <ran.xiaokai@zte.com.cn> Reported-by: Zeal Robot <zealci@zte.com.cn> Cc: Kees Cook <keescook@chromium.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Ohhoon Kwon <ohoono.kwon@samsung.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Stephen Brennan <stephen.s.brennan@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Feng Tang <feng.tang@intel.com> Cc: Yang Yang <yang.yang29@zte.com.cn> Cc: Ran Xiaokai <ran.xiaokai@zte.com.cn> Cc: Zeal Robot <zealci@zte.com.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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3a72917c |
| 23-Mar-2022 |
Hao Lee <haolee.swjtu@gmail.com> |
proc: alloc PATH_MAX bytes for /proc/${pid}/fd/ symlinks
It's not a standard approach that use __get_free_page() to alloc path buffer directly. We'd better use kmalloc and PATH_MAX.
PAGE_SIZE is
proc: alloc PATH_MAX bytes for /proc/${pid}/fd/ symlinks
It's not a standard approach that use __get_free_page() to alloc path buffer directly. We'd better use kmalloc and PATH_MAX.
PAGE_SIZE is different on different archs. An unlinked file with very long canonical pathname will readlink differently because "(deleted)" eats into a buffer. --adobriyan
[akpm@linux-foundation.org: remove now-unneeded cast]
Link: https://lkml.kernel.org/r/Ye1fCxyZZ0I5lgOL@localhost.localdomain Signed-off-by: Hao Lee <haolee.swjtu@gmail.com> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Christian Brauner <christian.brauner@ubuntu.com> Cc: Kees Cook <keescook@chromium.org> Cc: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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355f841a |
| 09-Feb-2022 |
Eric W. Biederman <ebiederm@xmission.com> |
tracehook: Remove tracehook.h
Now that all of the definitions have moved out of tracehook.h into ptrace.h, sched/signal.h, resume_user_mode.h there is nothing left in tracehook.h so remove it.
Upda
tracehook: Remove tracehook.h
Now that all of the definitions have moved out of tracehook.h into ptrace.h, sched/signal.h, resume_user_mode.h there is nothing left in tracehook.h so remove it.
Update the few files that were depending upon tracehook.h to bring in definitions to use the headers they need directly.
Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20220309162454.123006-13-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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Revision tags: v5.15.18, v5.15.17, v5.4.173, v5.15.16 |
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51a18734 |
| 19-Jan-2022 |
Qi Zheng <zhengqi.arch@bytedance.com> |
proc: convert the return type of proc_fd_access_allowed() to be boolean
Convert return type of proc_fd_access_allowed() and the 'allowed' in it to be boolean since the return type of ptrace_may_acce
proc: convert the return type of proc_fd_access_allowed() to be boolean
Convert return type of proc_fd_access_allowed() and the 'allowed' in it to be boolean since the return type of ptrace_may_access() is boolean.
Link: https://lkml.kernel.org/r/20211219024404.29779-1-zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Kees Cook <keescook@chromium.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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