On Tue, Dec 11, 2018 at 10:50:00PM -0800, David Miller wrote: > From: Xin Long <lucien.xin@xxxxxxxxx> > Date: Fri, 7 Dec 2018 14:30:32 +0800 > > > Without the support for the total_nr_elements's growing or shrinking > > dynamically, flex_array is not that 'flexible'. Like when users want > > to change the size, they have to redo flex_array_alloc and copy all > > the elements from the old to the new one. The worse thing is every > > element's memory gets changed. > > > > To implement flex_array_resize based on current code, the difficult > > thing is to process the size border of FLEX_ARRAY_BASE_BYTES_LEFT, > > where the base data memory may change to an array for the 2nd level > > data memory for growing, likewise for shrinking. > > > > To make this part easier, we separate the base data memory and define > > FLEX_ARRAY_BASE_SIZE as a same value of FLEX_ARRAY_PART_SIZE, as Neil > > suggested. When new size is crossing the border, the base memory is > > allocated as the array for the 2nd level data memory and its part[0] > > is pointed to the old base memory, and do the opposite for shrinking. > > > > But it doesn't do any memory allocation or shrinking for elements in > > flex_array_resize, as which should be done by flex_array_prealloc or > > flex_array_shrink called by users. No memory leaks can be caused by > > that. > > > > SCTP has benefited a lot from flex_array_resize() for managing its > > stream memory so far. > > > > v1->v2: > > Cc LKML and more developers. > > So I don't know what to do about this series. > > One of the responses stated that it has been proposed to remove flex_array > and I don't know what to make of that, nor can I tell if that makes this > series inappropriate or not. > I suggest xin respond to messageid 20180523011821.12165-6-kent.overstreet@xxxxxxxxx> and send a NAK, indicating that his patch seems like it will break the build, as, looking through it, it never removes flex_array calls from the sctp code. If kent reposts with a conversion of the sctp code to radix trees, we're done. If not, you can move forward with this commit. Neil
