0b964600d3
Add a missing case which could cause unnecessary page allocation but not directly use inplace I/O instead, which increases runtime extra memory footprint. The detail is, considering an online file-backed page, the right half of the page is chosen to be cached (e.g. the end page of a readahead request) and some of its data doesn't exist in managed cache, so the pcluster will be definitely kept in the submission chain. (IOWs, it cannot be decompressed without I/O, e.g., due to the bypass queue). Currently, DELAYEDALLOC/TRYALLOC cases can be downgraded as NOINPLACE, and stop online pages from inplace I/O. After this patch, unneeded page allocations won't be observed in pickup_page_for_submission() then. Link: https://lore.kernel.org/r/20210321183227.5182-1-hsiangkao@aol.com Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
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.