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8b90a9f819
If more than 16000 inflight AF_UNIX sockets exist and the garbage collector is not running, unix_(dgram|stream)_sendmsg() call unix_gc(). Also, they wait for unix_gc() to complete. In unix_gc(), all inflight AF_UNIX sockets are traversed at least once, and more if they are the GC candidate. Thus, sendmsg() significantly slows down with too many inflight AF_UNIX sockets. There is a small window to invoke multiple unix_gc() instances, which will then be blocked by the same spinlock except for one. Let's convert unix_gc() to use struct work so that it will not consume CPUs unnecessarily. Note WRITE_ONCE(gc_in_progress, true) is moved before running GC. If we leave the WRITE_ONCE() as is and use the following test to call flush_work(), a process might not call it. CPU 0 CPU 1 --- --- start work and call __unix_gc() if (work_pending(&unix_gc_work) || <-- false READ_ONCE(gc_in_progress)) <-- false flush_work(); <-- missed! WRITE_ONCE(gc_in_progress, true) Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://lore.kernel.org/r/20240123170856.41348-5-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> |
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arch | ||
block | ||
certs | ||
crypto | ||
Documentation | ||
drivers | ||
fs | ||
include | ||
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io_uring | ||
ipc | ||
kernel | ||
lib | ||
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mm | ||
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Makefile | ||
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.