diff options
| author | Johannes Weiner <hannes@cmpxchg.org> | 2025-12-15 12:57:53 -0500 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-01-20 19:24:47 -0800 |
| commit | 64dd89ae01f2708a508e028c28b7906e4702a9a7 (patch) | |
| tree | 2b1db1723e1b9c55d35e6e7dc04b8d6cd7fb2082 /include | |
| parent | 657a81fe3b41bd58c63e15ae282f992dda5c8eee (diff) | |
mm/block/fs: remove laptop_mode
Laptop mode was introduced to save battery, by delaying and consolidating
writes and thereby maximize the time rotating hard drives wouldn't have to
spin.
Luckily, rotating hard drives, with their high spin-up times and power
draw, are a thing of the past for battery-powered devices. Reclaim has
also since changed to not write single filesystem pages anymore, and
regular filesystem writeback is lumpy by design.
The juice doesn't appear worth the squeeze anymore. The footprint of the
feature is small, but nevertheless it's a complicating factor in mm,
block, filesystems. Developers don't think about it, and it likely hasn't
been tested with new reclaim and writeback changes in years.
Let's sunset it. Keep the sysctl with a deprecation warning around for a
few more cycles, but remove all functionality behind it.
[akpm@linux-foundation.org: fix Documentation/admin-guide/laptops/index.rst]
Link: https://lkml.kernel.org/r/20251216185201.GH905277@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Suggested-by: Christoph Hellwig <hch@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Deepanshu Kartikey <kartikey406@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/backing-dev-defs.h | 3 | ||||
| -rw-r--r-- | include/linux/writeback.h | 4 | ||||
| -rw-r--r-- | include/trace/events/writeback.h | 1 | ||||
| -rw-r--r-- | include/uapi/linux/sysctl.h | 2 |
4 files changed, 1 insertions, 9 deletions
diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h index 0217c1073735..c88fd4d37d1f 100644 --- a/include/linux/backing-dev-defs.h +++ b/include/linux/backing-dev-defs.h @@ -46,7 +46,6 @@ enum wb_reason { WB_REASON_VMSCAN, WB_REASON_SYNC, WB_REASON_PERIODIC, - WB_REASON_LAPTOP_TIMER, WB_REASON_FS_FREE_SPACE, /* * There is no bdi forker thread any more and works are done @@ -204,8 +203,6 @@ struct backing_dev_info { char dev_name[64]; struct device *owner; - struct timer_list laptop_mode_wb_timer; - #ifdef CONFIG_DEBUG_FS struct dentry *debug_dir; #endif diff --git a/include/linux/writeback.h b/include/linux/writeback.h index f48e8ccffe81..e530112c4b3a 100644 --- a/include/linux/writeback.h +++ b/include/linux/writeback.h @@ -328,9 +328,6 @@ struct dirty_throttle_control { bool dirty_exceeded; }; -void laptop_io_completion(struct backing_dev_info *info); -void laptop_sync_completion(void); -void laptop_mode_timer_fn(struct timer_list *t); bool node_dirty_ok(struct pglist_data *pgdat); int wb_domain_init(struct wb_domain *dom, gfp_t gfp); #ifdef CONFIG_CGROUP_WRITEBACK @@ -342,7 +339,6 @@ extern struct wb_domain global_wb_domain; /* These are exported to sysctl. */ extern unsigned int dirty_writeback_interval; extern unsigned int dirty_expire_interval; -extern int laptop_mode; void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty); unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh); diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h index 311a341e6fe4..b6f94e97788a 100644 --- a/include/trace/events/writeback.h +++ b/include/trace/events/writeback.h @@ -42,7 +42,6 @@ EM( WB_REASON_VMSCAN, "vmscan") \ EM( WB_REASON_SYNC, "sync") \ EM( WB_REASON_PERIODIC, "periodic") \ - EM( WB_REASON_LAPTOP_TIMER, "laptop_timer") \ EM( WB_REASON_FS_FREE_SPACE, "fs_free_space") \ EM( WB_REASON_FORKER_THREAD, "forker_thread") \ EMe(WB_REASON_FOREIGN_FLUSH, "foreign_flush") diff --git a/include/uapi/linux/sysctl.h b/include/uapi/linux/sysctl.h index 63d1464cb71c..6ea9ea8413fa 100644 --- a/include/uapi/linux/sysctl.h +++ b/include/uapi/linux/sysctl.h @@ -183,7 +183,7 @@ enum VM_LOWMEM_RESERVE_RATIO=20,/* reservation ratio for lower memory zones */ VM_MIN_FREE_KBYTES=21, /* Minimum free kilobytes to maintain */ VM_MAX_MAP_COUNT=22, /* int: Maximum number of mmaps/address-space */ - VM_LAPTOP_MODE=23, /* vm laptop mode */ + VM_BLOCK_DUMP=24, /* block dump mode */ VM_HUGETLB_GROUP=25, /* permitted hugetlb group */ VM_VFS_CACHE_PRESSURE=26, /* dcache/icache reclaim pressure */ |