Roman Gushchin f5fbe6b7ad writeback, cgroup: support switching multiple inodes at once
Currently only a single inode can be switched to another writeback
structure at once.  That means to switch an inode a separate
inode_switch_wbs_context structure must be allocated, and a separate rcu
callback and work must be scheduled.

It's fine for the existing ad-hoc switching, which is not happening that
often, but sub-optimal for massive switching required in order to release
a writeback structure.  To prepare for it, let's add a support for
switching multiple inodes at once.

Instead of containing a single inode pointer, inode_switch_wbs_context
will contain a NULL-terminated array of inode pointers.
inode_do_switch_wbs() will be called for each inode.

To optimize the locking bdi->wb_switch_rwsem, old_wb's and new_wb's
list_locks will be acquired and released only once altogether for all
inodes.  wb_wakeup() will be also be called only once.  Instead of calling
wb_put(old_wb) after each successful switch, wb_put_many() is introduced
and used.

Link: https://lkml.kernel.org/r/20210608230225.2078447-8-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Dennis Zhou <dennis@kernel.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Jan Kara <jack@suse.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-29 10:53:48 -07:00
2021-06-27 15:21:11 -07:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
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    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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