Hello, >> I see what you mean. >> >> I'm not sure, though. For most apps it's bad practice I think. If you get into >> realm of sophisticated, performance critical IO/storage managers, it would >> not surprise me if such concurrent buffer modifications could be allowed. >> We allow exactly such a thing in our pagecache layer. Although probably >> those would be using shared mmaps for their buffer cache. >> >> I think it is safest to make a default policy of asking for IOs against private >> cow-able mappings to be quiesced before fork, so there are no surprises >> or reliance on COW details in the mm. Do you think? > Yes, I agree that (and MADV_DONTFORK) is probably the best thing to have > in documentation. Otherwise it's a bit too hairy... I neglected this issue for years because Linus asked who need this and I couldn't find real world usecase. Ah, no, not exactly correct. Fujitsu proprietary database had such usecase. But they quickly fixed it. Then I couldn't find alternative usecase. I'm not sure why you say "hairy". Do you mean you have any use case of this? Thank you. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>