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Yonghong Song 203d7b054f bpf: Avoid iterating duplicated files for task_file iterator
Currently, task_file iterator iterates all files from all tasks.
This may potentially visit a lot of duplicated files if there are
many tasks sharing the same files, e.g., typical pthreads
where these pthreads and the main thread are sharing the same files.

This patch changed task_file iterator to skip a particular task
if that task shares the same files as its group_leader (the task
having the same tgid and also task->tgid == task->pid).
This will preserve the same result, visiting all files from all
tasks, and will reduce runtime cost significantl, e.g., if there are
a lot of pthreads and the process has a lot of open files.

Suggested-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/bpf/20200902023112.1672792-1-yhs@fb.com
2020-09-02 16:40:33 +02:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2020-09-01 13:22:59 -07:00
block block-5.9-2020-08-14 2020-08-15 20:36:42 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-08-14 13:09:15 -07:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2020-09-01 13:22:59 -07:00
drivers dpaa2-eth: add a dpaa2_eth_ prefix to all functions in dpaa2-eth-dcb.c 2020-09-01 13:23:47 -07:00
fs io_uring: ignore POLLIN for recvmsg on MSG_ERRQUEUE 2020-08-24 16:16:06 -07:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2020-09-01 13:22:59 -07:00
init bpf: Introduce sleepable BPF programs 2020-08-28 21:20:33 +02:00
ipc ipc/shm.c: remove the superfluous break 2020-08-12 10:58:02 -07:00
kernel bpf: Avoid iterating duplicated files for task_file iterator 2020-09-02 16:40:33 +02:00
lib netlink: remove duplicated nla_need_padding_for_64bit() check 2020-08-25 06:06:19 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2020-09-01 13:22:59 -07:00
net net: openvswitch: fixes crash if nf_conncount_init() fails 2020-09-01 13:23:23 -07:00
samples samples/bpf: Fix to xdpsock to avoid recycling frames 2020-08-31 23:00:43 +02:00
scripts Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2020-09-01 13:22:59 -07:00
security bpf: Implement bpf_local_storage for inodes 2020-08-25 15:00:04 -07:00
sound sound fixes for 5.9-rc2 2020-08-21 10:07:54 -07:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2020-09-01 13:22:59 -07:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt * PAE and PKU bugfixes for x86 2020-08-22 10:03:05 -07:00
.clang-format block: add bio_for_each_bvec_all() 2020-05-25 11:25:24 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: Add ZSTD-compressed files 2020-07-31 11:50:49 +02:00
.mailmap Merge branch 'akpm' (patches from Andrew) 2020-08-21 14:44:48 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS CREDITS: Replace HTTP links with HTTPS ones 2020-07-23 14:53:58 -06:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS net: phy: add Lynx PCS module 2020-08-31 12:52:33 -07:00
Makefile kbuild: remove redundant patterns in filter/filter-out 2020-08-18 20:16:46 +09:00
README

Linux kernel
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There are several guides for kernel developers and users. These guides can
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