Updating dirty bitmap by non-atomic set bit is safe?

DISCUSSION Takuya Yoshikawa 2 participants 3 messages Mar 23, 2010 KVM

Share & tools

Takuya Yoshikawa

author

2010-03-23 06:09 UTC #0 lore raw

Hi, does anybody knows about this?

Currently, dirty bitmap is updated by generic___set_le_bit(). I checked the git log and mail archives but could not find any explanation why replacing set_bit() by generic___set_le_bit() is safe.

Thanks,
Takuya

Avi Kivity

2010-03-23 09:18 UTC #1 lore raw

Quoted 8 lines · Takuya Yoshikawa

Hi, does anybody knows about this?
Currently, dirty bitmap is updated by generic___set_le_bit(). I checked the git log and mail archives but could not find any explanation why replacing set_bit() by generic___set_le_bit() is safe.

IIRC it's protected by the mmu spinlock.

Signature · 1 line

error compiling committee.c: too many arguments to function

Takuya Yoshikawa

author

2010-03-23 10:14 UTC #2 lore raw

Quoted 4 lines · Avi Kivity

Quoted 3 lines · Takuya Yoshikawa
Hi, does anybody knows about this?

Quoted 8 lines

Quoted 5 lines
Currently, dirty bitmap is updated by generic___set_le_bit(). I checked the git log and mail archives but could not find any explanation why replacing set_bit() by generic___set_le_bit() is safe.
IIRC it's protected by the mmu spinlock.

So the fact is the old version did extra protection, thank you.