4e63aeb5d0
Now we avoid throttling swap writes by determining whether the current process is kswapd (aka current_is_kswapd()), but swap writes can come from either kswapd or direct reclaim, so the swap writes from direct reclaim will still be throttled. When a process holds a lock to allocate a free page, and enters direct reclaim because there is no free memory, then it might trigger a hung due to the wbt throttling that causes other processes to fail to get the lock. Both kswapd and direct reclaim set the REQ_SWAP flag, so use REQ_SWAP instead of current_is_kswapd() to avoid throttling swap writes. Also renamed WBT_KSWAPD to WBT_SWAP and WBT_RWQ_KSWAPD to WBT_RWQ_SWAP. Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20240604030522.3686177-1-libaokun@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
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.