diff options
Diffstat (limited to 'Documentation/admin-guide')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 2 | ||||
| -rw-r--r-- | Documentation/admin-guide/mm/damon/start.rst | 2 | ||||
| -rw-r--r-- | Documentation/admin-guide/mm/damon/usage.rst | 11 | ||||
| -rw-r--r-- | Documentation/admin-guide/mm/transhuge.rst | 42 | ||||
| -rw-r--r-- | Documentation/admin-guide/mm/zswap.rst | 33 | ||||
| -rw-r--r-- | Documentation/admin-guide/sysctl/kernel.rst | 2 |
6 files changed, 63 insertions, 29 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index e019db1633fd..74ca438d2d6d 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -4603,7 +4603,7 @@ bit 2: print timer info bit 3: print locks info if CONFIG_LOCKDEP is on bit 4: print ftrace buffer - bit 5: replay all messages on consoles at the end of panic + bit 5: replay all kernel messages on consoles at the end of panic bit 6: print all CPUs backtrace (if available in the arch) bit 7: print only tasks in uninterruptible (blocked) state *Be aware* that this option may print a _lot_ of lines, diff --git a/Documentation/admin-guide/mm/damon/start.rst b/Documentation/admin-guide/mm/damon/start.rst index ede14b679d02..ec8c34b2d32f 100644 --- a/Documentation/admin-guide/mm/damon/start.rst +++ b/Documentation/admin-guide/mm/damon/start.rst @@ -175,4 +175,4 @@ Below command makes every memory region of size >=4K that has not accessed for $ sudo damo start --damos_access_rate 0 0 --damos_sz_region 4K max \ --damos_age 60s max --damos_action pageout \ - <pid of your workload> + --target_pid <pid of your workload> diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst index ff3a2dda1f02..2cae60b6f3ca 100644 --- a/Documentation/admin-guide/mm/damon/usage.rst +++ b/Documentation/admin-guide/mm/damon/usage.rst @@ -61,7 +61,7 @@ comma (","). │ :ref:`kdamonds <sysfs_kdamonds>`/nr_kdamonds │ │ :ref:`0 <sysfs_kdamond>`/state,pid,refresh_ms │ │ │ :ref:`contexts <sysfs_contexts>`/nr_contexts - │ │ │ │ :ref:`0 <sysfs_context>`/avail_operations,operations + │ │ │ │ :ref:`0 <sysfs_context>`/avail_operations,operations,addr_unit │ │ │ │ │ :ref:`monitoring_attrs <sysfs_monitoring_attrs>`/ │ │ │ │ │ │ intervals/sample_us,aggr_us,update_us │ │ │ │ │ │ │ intervals_goal/access_bp,aggrs,min_sample_us,max_sample_us @@ -188,9 +188,9 @@ details). At the moment, only one context per kdamond is supported, so only contexts/<N>/ ------------- -In each context directory, two files (``avail_operations`` and ``operations``) -and three directories (``monitoring_attrs``, ``targets``, and ``schemes``) -exist. +In each context directory, three files (``avail_operations``, ``operations`` +and ``addr_unit``) and three directories (``monitoring_attrs``, ``targets``, +and ``schemes``) exist. DAMON supports multiple types of :ref:`monitoring operations <damon_design_configurable_operations_set>`, including those for virtual address @@ -205,6 +205,9 @@ You can set and get what type of monitoring operations DAMON will use for the context by writing one of the keywords listed in ``avail_operations`` file and reading from the ``operations`` file. +``addr_unit`` file is for setting and getting the :ref:`address unit +<damon_design_addr_unit>` parameter of the operations set. + .. _sysfs_monitoring_attrs: contexts/<N>/monitoring_attrs/ diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst index 370fba113460..1654211cc6cf 100644 --- a/Documentation/admin-guide/mm/transhuge.rst +++ b/Documentation/admin-guide/mm/transhuge.rst @@ -225,6 +225,42 @@ to "always" or "madvise"), and it'll be automatically shutdown when PMD-sized THP is disabled (when both the per-size anon control and the top-level control are "never") +process THP controls +-------------------- + +A process can control its own THP behaviour using the ``PR_SET_THP_DISABLE`` +and ``PR_GET_THP_DISABLE`` pair of prctl(2) calls. The THP behaviour set using +``PR_SET_THP_DISABLE`` is inherited across fork(2) and execve(2). These calls +support the following arguments:: + + prctl(PR_SET_THP_DISABLE, 1, 0, 0, 0): + This will disable THPs completely for the process, irrespective + of global THP controls or madvise(..., MADV_COLLAPSE) being used. + + prctl(PR_SET_THP_DISABLE, 1, PR_THP_DISABLE_EXCEPT_ADVISED, 0, 0): + This will disable THPs for the process except when the usage of THPs is + advised. Consequently, THPs will only be used when: + - Global THP controls are set to "always" or "madvise" and + madvise(..., MADV_HUGEPAGE) or madvise(..., MADV_COLLAPSE) is used. + - Global THP controls are set to "never" and madvise(..., MADV_COLLAPSE) + is used. This is the same behavior as if THPs would not be disabled on + a process level. + Note that MADV_COLLAPSE is currently always rejected if + madvise(..., MADV_NOHUGEPAGE) is set on an area. + + prctl(PR_SET_THP_DISABLE, 0, 0, 0, 0): + This will re-enable THPs for the process, as if they were never disabled. + Whether THPs will actually be used depends on global THP controls and + madvise() calls. + + prctl(PR_GET_THP_DISABLE, 0, 0, 0, 0): + This returns a value whose bits indicate how THP-disable is configured: + Bits + 1 0 Value Description + |0|0| 0 No THP-disable behaviour specified. + |0|1| 1 THP is entirely disabled for this process. + |1|1| 3 THP-except-advised mode is set for this process. + Khugepaged controls ------------------- @@ -383,6 +419,8 @@ option: ``huge=``. It can have following values: always Attempt to allocate huge pages every time we need a new page; + Always try PMD-sized huge pages first, and fall back to smaller-sized + huge pages if the PMD-sized huge page allocation fails; never Do not allocate huge pages. Note that ``madvise(..., MADV_COLLAPSE)`` @@ -390,7 +428,9 @@ never is specified everywhere; within_size - Only allocate huge page if it will be fully within i_size. + Only allocate huge page if it will be fully within i_size; + Always try PMD-sized huge pages first, and fall back to smaller-sized + huge pages if the PMD-sized huge page allocation fails; Also respect madvise() hints; advise diff --git a/Documentation/admin-guide/mm/zswap.rst b/Documentation/admin-guide/mm/zswap.rst index fd3370aa43fe..283d77217c6f 100644 --- a/Documentation/admin-guide/mm/zswap.rst +++ b/Documentation/admin-guide/mm/zswap.rst @@ -53,26 +53,17 @@ Zswap receives pages for compression from the swap subsystem and is able to evict pages from its own compressed pool on an LRU basis and write them back to the backing swap device in the case that the compressed pool is full. -Zswap makes use of zpool for the managing the compressed memory pool. Each -allocation in zpool is not directly accessible by address. Rather, a handle is +Zswap makes use of zsmalloc for the managing the compressed memory pool. Each +allocation in zsmalloc is not directly accessible by address. Rather, a handle is returned by the allocation routine and that handle must be mapped before being accessed. The compressed memory pool grows on demand and shrinks as compressed -pages are freed. The pool is not preallocated. By default, a zpool -of type selected in ``CONFIG_ZSWAP_ZPOOL_DEFAULT`` Kconfig option is created, -but it can be overridden at boot time by setting the ``zpool`` attribute, -e.g. ``zswap.zpool=zsmalloc``. It can also be changed at runtime using the sysfs -``zpool`` attribute, e.g.:: - - echo zsmalloc > /sys/module/zswap/parameters/zpool - -The zsmalloc type zpool has a complex compressed page storage method, and it -can achieve great storage densities. +pages are freed. The pool is not preallocated. When a swap page is passed from swapout to zswap, zswap maintains a mapping -of the swap entry, a combination of the swap type and swap offset, to the zpool -handle that references that compressed swap page. This mapping is achieved -with a red-black tree per swap type. The swap offset is the search key for the -tree nodes. +of the swap entry, a combination of the swap type and swap offset, to the +zsmalloc handle that references that compressed swap page. This mapping is +achieved with a red-black tree per swap type. The swap offset is the search +key for the tree nodes. During a page fault on a PTE that is a swap entry, the swapin code calls the zswap load function to decompress the page into the page allocated by the page @@ -96,11 +87,11 @@ attribute, e.g.:: echo lzo > /sys/module/zswap/parameters/compressor -When the zpool and/or compressor parameter is changed at runtime, any existing -compressed pages are not modified; they are left in their own zpool. When a -request is made for a page in an old zpool, it is uncompressed using its -original compressor. Once all pages are removed from an old zpool, the zpool -and its compressor are freed. +When the compressor parameter is changed at runtime, any existing compressed +pages are not modified; they are left in their own pool. When a request is +made for a page in an old pool, it is uncompressed using its original +compressor. Once all pages are removed from an old pool, the pool and its +compressor are freed. Some of the pages in zswap are same-value filled pages (i.e. contents of the page have same value or repetitive pattern). These pages include zero-filled diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index 8b49eab937d0..f3ee807b5d8b 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -890,7 +890,7 @@ bit 1 print system memory info bit 2 print timer info bit 3 print locks info if ``CONFIG_LOCKDEP`` is on bit 4 print ftrace buffer -bit 5 replay all messages on consoles at the end of panic +bit 5 replay all kernel messages on consoles at the end of panic bit 6 print all CPUs backtrace (if available in the arch) bit 7 print only tasks in uninterruptible (blocked) state ===== ============================================ |