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BLK_START_PLUG(9) | Block Devices | BLK_START_PLUG(9) |
NAME¶
blk_start_plug - initialize blk_plug and track it inside the task_structSYNOPSIS¶
void blk_start_plug(struct blk_plug * plug);
ARGUMENTS¶
struct blk_plug * plugThe struct blk_plug that needs to be initialized
DESCRIPTION¶
Tracking blk_plug inside the task_struct will help with auto-flushing the pending I/O should the task end up blocking between blk_start_plug and blk_finish_plug. This is important from a performance perspective, but also ensures that we don't deadlock. For instance, if the task is blocking for a memory allocation, memory reclaim could end up wanting to free a page belonging to that request that is currently residing in our private plug. By flushing the pending I/O when the process goes to sleep, we avoid this kind of deadlock.COPYRIGHT¶
July 2017 | Kernel Hackers Manual 4.11 |