1BLK_START_PLUG(9)                Block Devices               BLK_START_PLUG(9)
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NAME

6       blk_start_plug - initialize blk_plug and track it inside the
7       task_struct
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SYNOPSIS

10       void blk_start_plug(struct blk_plug * plug);
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ARGUMENTS

13       plug
14           The struct blk_plug that needs to be initialized
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DESCRIPTION

17       Tracking blk_plug inside the task_struct will help with auto-flushing
18       the pending I/O should the task end up blocking between blk_start_plug
19       and blk_finish_plug. This is important from a performance perspective,
20       but also ensures that we don't deadlock. For instance, if the task is
21       blocking for a memory allocation, memory reclaim could end up wanting
22       to free a page belonging to that request that is currently residing in
23       our private plug. By flushing the pending I/O when the process goes to
24       sleep, we avoid this kind of deadlock.
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27Kernel Hackers Manual 3.10         June 2019                 BLK_START_PLUG(9)
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