-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 11/03/2014 03:42 PM, j.glisse@xxxxxxxxx wrote: > From: Jérôme Glisse <jglisse@xxxxxxxxxx> > > Page table is a common structure format most notably use by cpu > mmu. The arch depend page table code has strong tie to the > architecture which makes it unsuitable to be use by other non arch > specific code. > > This patch implement a generic and arch independent page table. It > is generic in the sense that entry size can be u64 or unsigned long > (or u32 too on 32bits arch). > > It is lockless in the sense that at any point in time you can have > concurrent thread updating the page table (removing or changing > entry) and faulting in the page table (adding new entry). This is > achieve by enforcing each updater and each faulter to take a range > lock. There is no exclusion on range lock, ie several thread can > fault or update the same range concurrently and it is the > responsability of the user to synchronize update to the page table > entry (pte), update to the page table directory (pdp) is under gpt > responsability. > > API usage pattern is : gpt_init() > > gpt_lock_update(lock_range) // User can update pte for instance by > using atomic bit operation // allowing complete lockless update. > gpt_unlock_update(lock_range) > > gpt_lock_fault(lock_range) // User can fault in pte but he is > responsible for avoiding thread // to concurrently fault the same > pte and for properly accounting // the number of pte faulted in the > pdp structure. gpt_unlock_fault(lock_range) // The new faulted pte > will only be visible to others updaters only // once all concurrent > faulter on the address unlock. > > Details on how the lockless concurrent updater and faulter works is > provided in the header file. > > Changed since v1: - Switch to macro implementation instead of using > arithmetic to accomodate the various size for table entry > (uint64_t, unsigned long, ...). This is somewhat less flexbile but > right now there is no use for the extra flexibility v1 was > offering. > > Signed-off-by: Jérôme Glisse <jglisse@xxxxxxxxxx> Never a fan of preprocessor magic, but I see why it's needed. Acked-by: Rik van Riel <riel@xxxxxxxxxx> - -- All rights reversed -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEcBAEBAgAGBQJUW/bgAAoJEM553pKExN6Dl6IH/i9rSRtvdO9+lf1cUe686XJb GZ8KOp3Qa+ac0W63NqEaY5W+Fi7qyZJdoRFLCyOHBSP44qg9yoEJz8IbdPVNRjGG lXyyfyOP0PY3wSakSP/IS3OIvapav6YPXiOIX7FlzPTReL+RWJPDYpmvi6S6nXgS PuVTedVT5yaZwcqh0CyfDZ8pQqxEBSyvdVY/ntia7hxtUk9Or/sWVaRn8RE1u6EZ xA5DtjqTB+UHmNtmTNe2B5i2TmvhIFYr+/ydCs76osR2e+UBcqQtnN3cdudZWyj3 Pk1c/7qtTqgS2pdiIkpjCKH5qXIszGM6vDSGCjM/4/7afX+vjk7UQDWeXGfzQFs= =ndqX -----END PGP SIGNATURE----- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>