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    SubjectRe: [PATCH 5.4 062/152] bcache: ignore pending signals when creating gc and allocator thread
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    On 3/3/20 11:12 AM, Greg Kroah-Hartman wrote:
    > On Tue, Mar 03, 2020 at 10:55:04AM -0700, Jens Axboe wrote:
    >> On 3/3/20 10:42 AM, Greg Kroah-Hartman wrote:
    >>> From: Coly Li <colyli@suse.de>
    >>>
    >>> [ Upstream commit 0b96da639a4874311e9b5156405f69ef9fc3bef8 ]
    >>>
    >>> When run a cache set, all the bcache btree node of this cache set will
    >>> be checked by bch_btree_check(). If the bcache btree is very large,
    >>> iterating all the btree nodes will occupy too much system memory and
    >>> the bcache registering process might be selected and killed by system
    >>> OOM killer. kthread_run() will fail if current process has pending
    >>> signal, therefore the kthread creating in run_cache_set() for gc and
    >>> allocator kernel threads are very probably failed for a very large
    >>> bcache btree.
    >>>
    >>> Indeed such OOM is safe and the registering process will exit after
    >>> the registration done. Therefore this patch flushes pending signals
    >>> during the cache set start up, specificly in bch_cache_allocator_start()
    >>> and bch_gc_thread_start(), to make sure run_cache_set() won't fail for
    >>> large cahced data set.
    >>
    >> Please drop this one, it's being reverted in mainline.
    >
    > Dropped from all trees now, thanks.

    Thanks!

    --
    Jens Axboe

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