diff options
Diffstat (limited to 'Documentation/admin-guide')
| -rw-r--r-- | Documentation/admin-guide/device-mapper/thin-provisioning.rst | 16 | ||||
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 38 |
2 files changed, 34 insertions, 20 deletions
diff --git a/Documentation/admin-guide/device-mapper/thin-provisioning.rst b/Documentation/admin-guide/device-mapper/thin-provisioning.rst index bafebf79da4b..b2fa49a5608a 100644 --- a/Documentation/admin-guide/device-mapper/thin-provisioning.rst +++ b/Documentation/admin-guide/device-mapper/thin-provisioning.rst @@ -80,11 +80,11 @@ less sharing than average you'll need a larger-than-average metadata device. As a guide, we suggest you calculate the number of bytes to use in the metadata device as 48 * $data_dev_size / $data_block_size but round it up -to 2MB if the answer is smaller. If you're creating large numbers of +to 2MiB if the answer is smaller. If you're creating large numbers of snapshots which are recording large amounts of change, you may find you need to increase this. -The largest size supported is 16GB: If the device is larger, +The largest size supported is 16GiB: If the device is larger, a warning will be issued and the excess space will not be used. Reloading a pool table @@ -107,13 +107,13 @@ Using an existing pool device $data_block_size gives the smallest unit of disk space that can be allocated at a time expressed in units of 512-byte sectors. -$data_block_size must be between 128 (64KB) and 2097152 (1GB) and a -multiple of 128 (64KB). $data_block_size cannot be changed after the +$data_block_size must be between 128 (64KiB) and 2097152 (1GiB) and a +multiple of 128 (64KiB). $data_block_size cannot be changed after the thin-pool is created. People primarily interested in thin provisioning -may want to use a value such as 1024 (512KB). People doing lots of -snapshotting may want a smaller value such as 128 (64KB). If you are +may want to use a value such as 1024 (512KiB). People doing lots of +snapshotting may want a smaller value such as 128 (64KiB). If you are not zeroing newly-allocated data, a larger $data_block_size in the -region of 256000 (128MB) is suggested. +region of 262144 (128MiB) is suggested. $low_water_mark is expressed in blocks of size $data_block_size. If free space on the data device drops below this level then a dm event @@ -291,7 +291,7 @@ i) Constructor error_if_no_space: Error IOs, instead of queueing, if no space. - Data block size must be between 64KB (128 sectors) and 1GB + Data block size must be between 64KiB (128 sectors) and 1GiB (2097152 sectors) inclusive. diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index c1a5cd991f2e..747a55abf494 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1828,6 +1828,27 @@ backtraces on all cpus. Format: 0 | 1 + hash_pointers= + [KNL,EARLY] + By default, when pointers are printed to the console + or buffers via the %p format string, that pointer is + "hashed", i.e. obscured by hashing the pointer value. + This is a security feature that hides actual kernel + addresses from unprivileged users, but it also makes + debugging the kernel more difficult since unequal + pointers can no longer be compared. The choices are: + Format: { auto | always | never } + Default: auto + + auto - Hash pointers unless slab_debug is enabled. + always - Always hash pointers (even if slab_debug is + enabled). + never - Never hash pointers. This option should only + be specified when debugging the kernel. Do + not use on production kernels. The boot + param "no_hash_pointers" is an alias for + this mode. + hashdist= [KNL,NUMA] Large hashes allocated during boot are distributed across NUMA nodes. Defaults on for 64-bit NUMA, off otherwise. @@ -4216,18 +4237,7 @@ no_hash_pointers [KNL,EARLY] - Force pointers printed to the console or buffers to be - unhashed. By default, when a pointer is printed via %p - format string, that pointer is "hashed", i.e. obscured - by hashing the pointer value. This is a security feature - that hides actual kernel addresses from unprivileged - users, but it also makes debugging the kernel more - difficult since unequal pointers can no longer be - compared. However, if this command-line option is - specified, then all normal pointers will have their true - value printed. This option should only be specified when - debugging the kernel. Please do not use on production - kernels. + Alias for "hash_pointers=never". nohibernate [HIBERNATION] Disable hibernation and resume. @@ -6644,6 +6654,10 @@ Documentation/admin-guide/mm/slab.rst. (slub_debug legacy name also accepted for now) + Using this option implies the "no_hash_pointers" + option which can be undone by adding the + "hash_pointers=always" option. + slab_max_order= [MM] Determines the maximum allowed order for slabs. A high setting may cause OOMs due to memory |