On Fri, Nov 08, 2024 at 01:57:06PM +0000, Lorenzo Stoakes wrote: > Locking around VMAs is complicated and confusing. While we have a number of > disparate comments scattered around the place, we seem to be reaching a > level of complexity that justifies a serious effort at clearly documenting > how locks are expected to be used when it comes to interacting with > mm_struct and vm_area_struct objects. > > This is especially pertinent as regards the efforts to find sensible > abstractions for these fundamental objects in kernel rust code whose > compiler strictly requires some means of expressing these rules (and > through this expression, self-document these requirements as well as > enforce them). > > The document limits scope to mmap and VMA locks and those that are > immediately adjacent and relevant to them - so additionally covers page > table locking as this is so very closely tied to VMA operations (and relies > upon us handling these correctly). > > The document tries to cover some of the nastier and more confusing edge > cases and concerns especially around lock ordering and page table teardown. > > The document is split between generally useful information for users of mm > interfaces, and separately a section intended for mm kernel developers > providing a discussion around internal implementation details. > > Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx> Hi Andrew, As Murphy's law so often dictates, I noticed a few small mistakes moments after sending the patch... :) I enclose a fix-patch to correct these, basically a typo and some small prose fixes. I have also updated https://ljs.io/v2/mm/process_addrs to reflect this. Thanks, Lorenzo ----8<----
