No description
  • C 98.2%
  • Assembly 1%
  • Makefile 0.3%
  • Shell 0.2%
  • Python 0.1%
Find a file
Repository files (latest commit first)
Filename Latest commit message Latest commit date
Ming Lei 92524fa123 scsi: core: avoid preallocating big SGL for protection information
scsi_mq_setup_tags() currently preallocates a big buffer for protection
SGL entries. scsi_mq_sgl_size() is used to determine the size for both data
and protection information scatterlists but the protection buffer is
usually much smaller. For example, one 512-byte sector needs 8 bytes of
protection information. Given that the maximum number of sectors for one
request is 2560 (BLK_DEF_MAX_SECTORS) sectors, the max protection
information buffer size is just 20K.

The protection information segment count generally matches the number of
bios in the request. As a result, the typical actual number of segments
won't be very big. And should the need arise, allocating a bigger SGL from
slab is fast enough.

Pre-allocate only one SGL entry for protection information and switch to
runtime allocation in case that the protection information segment number
is bigger than 1. This reduces memory tied up by static command
allocations. For example, 500+ MB is saved on single lpfc HBA.

[mkp: attempted to clarify commit desc]

Cc: Christoph Hellwig <hch@lst.de>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Ewan D. Milne <emilne@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2019-06-20 15:21:33 -04:00
arch Merge branch 'akpm' (patches from Andrew) 2019-05-19 12:15:32 -07:00
block for-5.2/block-post-20190516 2019-05-16 19:08:15 -07:00
certs
crypto Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2019-05-07 22:03:58 -07:00
Documentation Merge branch 'akpm' (patches from Andrew) 2019-05-19 12:15:32 -07:00
drivers scsi: core: avoid preallocating big SGL for protection information 2019-06-20 15:21:33 -04:00
fs This pull request contains the following fixes for UBIFS: 2019-05-19 15:22:03 -07:00
include scsi: lib/sg_pool.c: improve APIs for allocating sg pool 2019-06-20 15:21:33 -04:00
init initramfs: don't free a non-existent initrd 2019-05-18 15:52:26 -07:00
ipc ipc: do cyclic id allocation for the ipc object. 2019-05-14 19:52:52 -07:00
kernel Merge branch 'akpm' (patches from Andrew) 2019-05-19 12:15:32 -07:00
lib scsi: lib/sg_pool.c: improve APIs for allocating sg pool 2019-06-20 15:21:33 -04:00
LICENSES
mm Merge branch 'akpm' (patches from Andrew) 2019-05-19 12:15:32 -07:00
net scsi: lib/sg_pool.c: improve APIs for allocating sg pool 2019-06-20 15:21:33 -04:00
samples samples: guard sub-directories with CONFIG options 2019-05-18 11:29:01 +09:00
scripts kconfig: use 'else ifneq' for Makefile to improve readability 2019-05-19 09:34:35 +09:00
security Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-05-13 15:15:00 -07:00
sound sound fixes for 5.2-rc1 2019-05-17 13:57:54 -07:00
tools Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-05-19 11:20:22 -07:00
usr
virt * ARM: support for SVE and Pointer Authentication in guests, PMU improvements 2019-05-17 10:33:30 -07:00
.clang-format
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes
.gitignore .gitignore: exclude .get_maintainer.ignore and .gitattributes 2019-05-18 11:49:54 +09:00
.mailmap A reasonably busy cycle for docs, including: 2019-05-08 12:42:50 -07:00
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Kbuild updates for v5.2 (2nd) 2019-05-19 11:53:58 -07:00
Makefile Linux 5.2-rc1 2019-05-19 15:47:09 -07:00
README

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.