Re: [PATCH 0/2] make VM_SOFTDIRTY a sticky VMA flag

On Wed, Nov 19, 2025 at 04:09:49PM +0300, Cyrill Gorcunov wrote:
> On Mon, Nov 17, 2025 at 07:57:30PM +0000, Lorenzo Stoakes wrote:
> ...
> > > I recall correctly that initially, merging vma-s with different
> > > VM_SORTDIRTY bit values was not allowed. It was a bit surprising that
> > > this behavior was changed by Cyrill in 34228d473efe.  Cyrill was an
> > > active CRIU contributor at the time, so we can't even blame anyone for
> > > breaking CRIU :).
> >
> > Well I think Cyrill is in the right here :) the problem described there -
> > that of hitting the max_map_count simply due to failed VM_SOFTDIRTY merges
> > - is very serious and clearly highlights the issue that arises from not
> > merging these - that is VMA fragmentation.
>
> Hi guys! Happen to miss this thread due to high message traffic, thanks
> for CC'ing me ;) Yeah, disability to merge VMAs due to softdirty bit has
> been a serious issue, so better criu to dump more (redundant) memory
> than apps got broken. As to this patch series, I think it is good, thanks
> a huge Lorenzo!
>
> Acked-by: Cyrill Gorcunov <[email protected]>

Thanks :)