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authorJason A. Donenfeld <Jason@zx2c4.com>2022-09-22 19:46:04 +0300
committerJason A. Donenfeld <Jason@zx2c4.com>2022-09-28 19:17:30 +0300
commit9ee0507e896b45af6d65408c77815800bce30008 (patch)
treeee7e977c2029f6710aaaa2df9f5c7a4addc9f7b6 /drivers/char
parente78a802a7b4febf53f2a92842f494b01062d85a8 (diff)
downloadlinux-9ee0507e896b45af6d65408c77815800bce30008.tar.xz
random: avoid reading two cache lines on irq randomness
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>
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/random.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 2f370aa248b2..a90d96f4b3bb 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -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) = {