Baokun Li 6347558764 ext4: refactor choose group to scan group
This commit converts the `choose group` logic to `scan group` using
previously prepared helper functions. This allows us to leverage xarrays
for ordered non-linear traversal, thereby mitigating the "bouncing" issue
inherent in the `choose group` mechanism.

This also decouples linear and non-linear traversals, leading to cleaner
and more readable code.

Key changes:

 * ext4_mb_choose_next_group() is refactored to ext4_mb_scan_groups().

 * Replaced ext4_mb_good_group() with ext4_mb_scan_group() in non-linear
   traversals, and related functions now return error codes instead of
   group info.

 * Added ext4_mb_scan_groups_linear() for performing linear scans starting
   from a specific group for a set number of times.

 * Linear scans now execute up to sbi->s_mb_max_linear_groups times,
   so ac_groups_linear_remaining is removed as it's no longer used.

 * ac->ac_criteria is now used directly instead of passing cr around.
   Also, ac->ac_criteria is incremented directly after groups scan fails
   for the corresponding criteria.

 * Since we're now directly scanning groups instead of finding a good group
   then scanning, the following variables and flags are no longer needed,
   s_bal_cX_groups_considered is sufficient.

    s_bal_p2_aligned_bad_suggestions
    s_bal_goal_fast_bad_suggestions
    s_bal_best_avail_bad_suggestions
    EXT4_MB_CR_POWER2_ALIGNED_OPTIMIZED
    EXT4_MB_CR_GOAL_LEN_FAST_OPTIMIZED
    EXT4_MB_CR_BEST_AVAIL_LEN_OPTIMIZED

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20250714130327.1830534-17-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-07-25 09:14:17 -04:00
2025-06-21 07:34:28 -07:00
2025-02-19 14:53:27 -07:00
2025-06-29 13:09:04 -07:00
2024-03-18 03:36:32 -06:00

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
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText 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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