On Wed, Apr 24, 2013 at 4:26 AM, John Stultz <john.stultz@xxxxxxxxxx> wrote: > On 04/22/2013 11:51 PM, Dmitry Vyukov wrote: >> >> Just want to make sure our case does not fall out of the discussion: >> https://code.google.com/p/thread-sanitizer/wiki/VolatileRanges > > > Yes, while I forgot to mention it in the summary, I did bring it up briefly, > but I cannot claim to have done it justice. Thanks! > Personally, while I suspect we might be able to support your desired > semantics (ie: mark once volatile, always zero-fill, no sigbus) via a mode > flag > > >> While reading your email, I remembered that we actually have some >> pages mapped from a file inside the range. So it's like 70TB of ANON >> mapping + few pages in the middle mapped from FILE. The file is mapped >> with MAP_PRIVATE + PROT_READ, it's read-only and not shared. >> But we want to mark the volatile range only once on startup, so >> performance is not a serious concern (while the function in executed >> in say no more than 10ms). >> If the mixed ANON+FILE ranges becomes a serious problem, we are ready >> to remove FILE mappings, because it's only an optimization. I.e. we >> can make it pure ANON mapping. > > Well, in my mind, the MAP_PRIVATE mappings are semantically the same as > anonymous memory with regards to volatility. So I hope this wouldn't be an > issue. Ah, I see, so you more concerned about SHARED rather than FILE. We do NOT have any SHARED regions. -- 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>