91dcad18d3
Various phases of fsck involve checking references from one btree to another: this means doing a sequential scan of one btree, and then mostly random access into the second. This is particularly painful for checking extents <-> backpointers; we can prefetch btree node access on the sequential scan, but not on the random access portion, and this is particularly painful on spinning rust, where we'd like to keep the pipeline fairly full of btree node reads so that the elevator can reduce seeking. This patch implements prefetching and pinning of the portion of the btree that we'll be doing random access to. We already calculate how much of the random access btree will fit in memory so it's a fairly straightforward change. This will put more pressure on system memory usage, so we introduce a new option, fsck_memory_usage_percent, which is the percentage of total system ram that fsck is allowed to pin. Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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 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.