30a7a9b17c
For areas allocated via vmalloc_xxx() APIs, it searches for unmapped area to reserve and allocates new pages to map into, please see function __vmalloc_node_range(). During the process, flag VM_UNINITIALIZED is set in vm->flags to indicate that the pages allocation and mapping haven't been done, until clear_vm_uninitialized_flag() is called to clear VM_UNINITIALIZED. For this kind of area, if VM_UNINITIALIZED is still set, let's ignore it in vread() because pages newly allocated and being mapped in that area only contains zero data. reading them out by aligned_vread() is wasting time. Link: https://lkml.kernel.org/r/20230206084020.174506-6-bhe@redhat.com Signed-off-by: Baoquan He <bhe@redhat.com> Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com> Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Dan Carpenter <error27@gmail.com> Cc: Stephen Brennan <stephen.s.brennan@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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.