Kernel/linux
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2025-01-09 23:00:21 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

random: avoid reading two cache lines on irq randomness

Browse Source 
In order to avoid reading and dirtying two cache lines on every IRQ,
move the work_struct to the bottom of the fast_pool struct. add_
interrupt_randomness() always touches .pool and .count, which are
currently split, because .mix pushes everything down. Instead, move .mix
to the bottom, so that .pool and .count are always in the first cache
line, since .mix is only accessed when the pool is full.

Fixes: 58340f8e952b ("random: defer fast pool mixing to worker")
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Jason A. Donenfeld 2022-09-22 18:46:04 +02:00
parent e78a802a7b
commit 9ee0507e89
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/char/random.c
View File

@ -918,10 +918,10 @@ EXPORT_SYMBOL_GPL(unregister_random_vmfork_notifier);
#endif
struct fast_pool {
struct work_struct mix;
unsigned long pool[4];
unsigned long last;
unsigned int count;
struct work_struct mix;
};
static DEFINE_PER_CPU(struct fast_pool, irq_randomness) = {