On Sat, Apr 10, 2021 at 9:16 AM Ilias Apalodimas <ilias.apalodimas@xxxxxxxxxx> wrote: > > Hi Matthew > > On Sat, Apr 10, 2021 at 04:48:24PM +0100, Matthew Wilcox wrote: > > On Sat, Apr 10, 2021 at 12:37:58AM +0200, Matteo Croce wrote: > > > This is needed by the page_pool to avoid recycling a page not allocated > > > via page_pool. > > > > Is the PageType mechanism more appropriate to your needs? It wouldn't > > be if you use page->_mapcount (ie mapping it to userspace). > > Interesting! > Please keep in mind this was written ~2018 and was stale on my branches for > quite some time. So back then I did try to use PageType, but had not free > bits. Looking at it again though, it's cleaned up. So yes I think this can > be much much cleaner. Should we go and define a new PG_pagepool? > > Can this page_pool be used for TCP RX zerocopy? If yes then PageType can not be used. There is a recent discussion [1] on memcg accounting of TCP RX zerocopy and I am wondering if this work can somehow help in that regard. I will take a look at the series. [1] https://lore.kernel.org/linux-mm/20210316013003.25271-1-arjunroy.kdev@xxxxxxxxx/
