kernel/linux.git/Documentation/admin-guide/blockdev/zram.rst, branch v6.6.132

zram: split memory-tracking and ac-time tracking

2024-12-14T18:59:44+00:00

[ Upstream commit a7a0350583ba51d8cde6180bb51d704b89a3b29e ] ZRAM_MEMORY_TRACKING enables two features: - per-entry ac-time tracking - debugfs interface The latter one is the reason why memory-tracking depends on DEBUG_FS, while the former one is used far beyond debugging these days. Namely ac-time is used for fine grained writeback of idle entries (pages). Move ac-time tracking under its own config option so that it can be enabled (along with writeback) on systems without DEBUG_FS. [senozhatsky@chromium.org: ifdef fixup, per Dmytro] Link: https://lkml.kernel.org/r/20231117013543.540280-1-senozhatsky@chromium.org Link: https://lkml.kernel.org/r/20231115024223.4133148-1-senozhatsky@chromium.org Signed-off-by: Sergey Senozhatsky Cc: Minchan Kim Cc: Dmytro Maluka Signed-off-by: Andrew Morton Stable-dep-of: d37da422edb0 ("zram: clear IDLE flag in mark_idle()") Signed-off-by: Sasha Levin

zram: add incompressible flag to read_block_state()

2022-11-30T23:58:53+00:00

Add a new flag to zram block state that shows if the page is incompressible: that none of the algorithm (including secondary ones) could compress it. Link: https://lkml.kernel.org/r/20221109115047.2921851-14-senozhatsky@chromium.org Suggested-by: Minchan Kim Signed-off-by: Sergey Senozhatsky Acked-by: Minchan Kim Cc: Alexey Romanov Cc: Nhat Pham Cc: Nitin Gupta Cc: Suleiman Souhlal Signed-off-by: Andrew Morton

zram: add incompressible writeback

2022-11-30T23:58:53+00:00

Add support for incompressible pages writeback: echo incompressible > /sys/block/zramX/writeback Link: https://lkml.kernel.org/r/20221109115047.2921851-13-senozhatsky@chromium.org Signed-off-by: Sergey Senozhatsky Acked-by: Minchan Kim Cc: Alexey Romanov Cc: Nhat Pham Cc: Nitin Gupta Cc: Suleiman Souhlal Signed-off-by: Andrew Morton

documentation: add zram recompression documentation

2022-11-30T23:58:52+00:00

Document user-space visible device attributes that are enabled by ZRAM_MULTI_COMP. Link: https://lkml.kernel.org/r/20221109115047.2921851-12-senozhatsky@chromium.org Signed-off-by: Sergey Senozhatsky Acked-by: Minchan Kim Cc: Alexey Romanov Cc: Nhat Pham Cc: Nitin Gupta Cc: Suleiman Souhlal Signed-off-by: Andrew Morton

zram: add recompress flag to read_block_state()

2022-11-30T23:58:51+00:00

Add a new flag to zram block state that shows if the page was recompressed (using alternative compression algorithm). Link: https://lkml.kernel.org/r/20221109115047.2921851-6-senozhatsky@chromium.org Signed-off-by: Sergey Senozhatsky Acked-by: Minchan Kim Cc: Alexey Romanov Cc: Nhat Pham Cc: Nitin Gupta Cc: Suleiman Souhlal Signed-off-by: Andrew Morton

zram: add a huge_idle writeback mode

2022-04-29T21:36:59+00:00

Today it's only possible to write back as a page, idle, or huge. A user might want to writeback pages which are huge and idle first as these idle pages do not require decompression and make a good first pass for writeback. Idle writeback specifically has the advantage that a refault is unlikely given that the page has been swapped for some amount of time without being refaulted. Huge writeback has the advantage that you're guaranteed to get the maximum benefit from a single page writeback, that is, you're reclaiming one full page of memory. Pages which are compressed in zram being written back result in some benefit which is always less than a page size because of the fact that it was compressed. The primary use of this is for minimizing refaults in situations where the device has to be sensitive to storage endurance. On ChromeOS we have devices with slow eMMC and repeated writes and refaults can negatively affect performance and endurance. Link: https://lkml.kernel.org/r/20220322215821.1196994-1-bgeffon@google.com Signed-off-by: Brian Geffon Acked-by: Minchan Kim Cc: Nitin Gupta Cc: Sergey Senozhatsky Signed-off-by: Andrew Morton

docs: Fix wording in optional zram feature docs

2022-02-15T23:32:27+00:00

This fixes some simple grammar errors in the documentation for zram, specifically errors in the optional feature section of the zram documentation. Signed-off-by: Ethan Dye Link: https://lore.kernel.org/r/20220207235442.95090-1-mrtops03@gmail.com Signed-off-by: Jonathan Corbet

zram: introduce an aged idle interface

2021-11-06T20:30:43+00:00

This change introduces an aged idle interface to the existing idle sysfs file for zram. When CONFIG_ZRAM_MEMORY_TRACKING is enabled the idle file now also accepts an integer argument. This integer is the age (in seconds) of pages to mark as idle. The idle file still supports 'all' as it always has. This new approach allows for much more control over which pages get marked as idle. [bgeffon@google.com: use IS_ENABLED and cleanup comment] Link: https://lkml.kernel.org/r/20210924161128.1508015-1-bgeffon@google.com [bgeffon@google.com: Sergey's cleanup suggestions] Link: https://lkml.kernel.org/r/20210929143056.13067-1-bgeffon@google.com Link: https://lkml.kernel.org/r/20210923130115.1344361-1-bgeffon@google.com Signed-off-by: Brian Geffon Acked-by: Minchan Kim Reviewed-by: Sergey Senozhatsky Cc: Nitin Gupta Cc: Jonathan Corbet Cc: Suleiman Souhlal Cc: Jesse Barnes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'akpm' (patches from Andrew)

2020-12-15T20:53:37+00:00

Merge misc updates from Andrew Morton: - a few random little subsystems - almost all of the MM patches which are staged ahead of linux-next material. I'll trickle to post-linux-next work in as the dependents get merged up. Subsystems affected by this patch series: kthread, kbuild, ide, ntfs, ocfs2, arch, and mm (slab-generic, slab, slub, dax, debug, pagecache, gup, swap, shmem, memcg, pagemap, mremap, hmm, vmalloc, documentation, kasan, pagealloc, memory-failure, hugetlb, vmscan, z3fold, compaction, oom-kill, migration, cma, page-poison, userfaultfd, zswap, zsmalloc, uaccess, zram, and cleanups). * emailed patches from Andrew Morton : (200 commits) mm: cleanup kstrto*() usage mm: fix fall-through warnings for Clang mm: slub: convert sysfs sprintf family to sysfs_emit/sysfs_emit_at mm: shmem: convert shmem_enabled_show to use sysfs_emit_at mm:backing-dev: use sysfs_emit in macro defining functions mm: huge_memory: convert remaining use of sprintf to sysfs_emit and neatening mm: use sysfs_emit for struct kobject * uses mm: fix kernel-doc markups zram: break the strict dependency from lzo zram: add stat to gather incompressible pages since zram set up zram: support page writeback mm/process_vm_access: remove redundant initialization of iov_r mm/zsmalloc.c: rework the list_add code in insert_zspage() mm/zswap: move to use crypto_acomp API for hardware acceleration mm/zswap: fix passing zero to 'PTR_ERR' warning mm/zswap: make struct kernel_param_ops definitions const userfaultfd/selftests: hint the test runner on required privilege userfaultfd/selftests: fix retval check for userfaultfd_open() userfaultfd/selftests: always dump something in modes userfaultfd: selftests: make __{s,u}64 format specifiers portable ...

zram: add stat to gather incompressible pages since zram set up

2020-12-15T20:13:47+00:00

Currently, zram supports the stat via /sys/block/zram/mm_stat to represent how many of incompressible pages are stored at the moment but it couldn't show how many times incompressible pages were wrote down since zram set up. It's also good indication to see how zram is effective in the system. Link: https://lkml.kernel.org/r/20201130201907.1284910-1-minchan@kernel.org Signed-off-by: Minchan Kim Reviewed-by: Sergey Senozhatsky Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds