4ba67ef3a1
With the previous change, struct dqs->stall_thrs will be in the hot path
(at queue side), even if DQS is disabled.
The other fields accessed in this function (last_obj_cnt and num_queued)
are in the first cache line, let's move this field (stall_thrs) to the
very first cache line, since there is a hole there.
This does not change the structure size, since it moves an short (2
bytes) to 4-bytes whole in the first cache line.
This is the new structure format now:
struct dql {
unsigned int num_queued;
unsigned int last_obj_cnt;
...
short unsigned int stall_thrs;
/* XXX 2 bytes hole, try to pack */
...
/* --- cacheline 1 boundary (64 bytes) --- */
...
/* Longest stall detected, reported to user */
short unsigned int stall_max;
/* XXX 2 bytes hole, try to pack */
};
Also, read the stall_thrs (now in the very first cache line) earlier,
together with dql->num_queued (also in the first cache line).
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://lore.kernel.org/r/20240411192241.2498631-5-leitao@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.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 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.