> -----Original Message----- > From: Xen-devel <xen-devel-bounces@xxxxxxxxxxxxxxxxxxxx> On Behalf Of > SeongJae Park > Sent: 04 December 2019 11:34 > To: konrad.wilk@xxxxxxxxxx; roger.pau@xxxxxxxxxx; axboe@xxxxxxxxx > Cc: sj38.park@xxxxxxxxx; xen-devel@xxxxxxxxxxxxxxxxxxxx; linux- > block@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Park, Seongjae > <sjpark@xxxxxxxxxx> > Subject: [Xen-devel] [PATCH 0/2] xen/blkback: Aggressively shrink page > pools if a memory pressure is detected > > Each `blkif` has a free pages pool for the grant mapping. The size of > the pool starts from zero and be increased on demand while processing > the I/O requests. If current I/O requests handling is finished or 100 > milliseconds has passed since last I/O requests handling, it checks and > shrinks the pool to not exceed the size limit, `max_buffer_pages`. > > Therefore, `blkfront` running guests can cause a memory pressure in the > `blkback` running guest by attaching arbitrarily large number of block > devices and inducing I/O. OOI... How do guests unilaterally cause the attachment of arbitrary numbers of PV devices? Paul
