So the idea of item 3 might sound and lead to seldom usage of '--base-virtaddress'. Reserve an address hole big enough before hugepage almost cost nothing.
> -----Original Message----- > From: Jonas Pfefferle [mailto:[email protected]] > Sent: Wednesday, January 3, 2018 5:22 PM > To: Xueming(Steven) Li <[email protected]>; Burakov, Anatoly > <[email protected]> > Cc: [email protected]; [email protected]; Thomas Monjalon > <[email protected]> > Subject: Re: [dpdk-dev] [PATCH] mem: warn if address hint is not respected > > Hi Xueming, > > Correct --base-virtaddr was introduced for that purpose. There are > multiple reasons why the address layout of the secondary process might > look different: reasons you mentioned in 2), ASLR etc. I believe there is > no way to avoid this in real world use cases. The reason for this > particular patch is that the address hint (--base-virtaddr) is sometimes > not respected and the kernel falls back to just reserving any address it > can find to satisfy the mapping (see discussion on the patch), i.e. > effectively rendering --base-virtaddr useless. > > Regards, > Jonas (new email address) > > > On Tue, 26 Dec 2017 15:56:10 +0000 > "Xueming(Steven) Li" <[email protected]> wrote: > > Hi Jonas, > > > > Seems you are trying to use --base-virtaddr to resolve address > >conflicts in secondary, I'm wondering how this happened and how to > >avoid it: > > 1. what's your hugepage side? Hugepage mmap is size aligned, maybe 1G > >works? > > 2. is there more libs loaded in secondary process or memory usage > >before EAL init? > > 3. Since address allocated in one direction, I'm thinking to reserve a > >larger "hop" address space as MAP_ANONYMOUS, allocate hugepage, then > >release "hop". That essentially reserve an address space big enough > >for secondary, and most important the hop size is easy to estimate > >than --base-virtaddr. > > > > Thanks, > > Xueming(Steven) > > > >> -----Original Message----- > >> From: dev [mailto:[email protected]] On Behalf Of Jonas > >>Pfefferle1 > >> Sent: Wednesday, November 8, 2017 7:52 PM > >> To: Burakov, Anatoly <[email protected]> > >> Cc: [email protected]; [email protected]; Thomas Monjalon > >><[email protected]> > >> Subject: Re: [dpdk-dev] [PATCH] mem: warn if address hint is not > >>respected > >> > >> "Burakov, Anatoly" <[email protected]> wrote on 11/07/2017 > >> 02:54:24 > >> PM: > >> > >> > From: "Burakov, Anatoly" <[email protected]> > >> > To: Thomas Monjalon <[email protected]> > >> > Cc: [email protected], Jonas Pfefferle <[email protected]>, > >> [email protected] > >> > Date: 11/07/2017 02:54 PM > >> > Subject: Re: [dpdk-dev] [PATCH] mem: warn if address hint is not > >> respected > >> > > >> > On 06-Nov-17 8:26 PM, Thomas Monjalon wrote: > >> > > 31/10/2017 10:08, Jonas Pfefferle: > >> > >> Print a warning if the --base-virtaddr hint is not respected > >>since > >> > >> this might lead to problems when mapping memory in the > >>secondary > >> > >> process. > >> > >> > >> > >> Signed-off-by: Jonas Pfefferle <[email protected]> > >> > > > >> > > Anatoly, please review this patch. > >> > > It does not seem to fix something, so it is candidate for 18.02. > >> > > > >> > > >> > For some reason my Thunderbird ate the original email, so i'll > >>reply > >> > to this one. > >> > > >> > One nitpick would be that we're calling get_virtual_area many > >>times > >> > and it would probably be a good idea to make pagesize static and > >>call > >> > sysconf only once. Otherwise, > >> > >> We should address this in a separate patch and introduce a pagesize > >>function for everyone to use. sysconf is used like this all over the > >>place. > >> > >> > > >> > Acked-by: Anatoly Burakov <[email protected]> > >> > > >> > -- > >> > Thanks, > >> > Anatoly > >> >
