Messages in this thread | | | Subject | Re: [PATCH 0/2] optimise sqe-to-req flags | From | Jens Axboe <> | Date | Fri, 17 Jan 2020 15:49:49 -0700 |
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On 1/17/20 3:41 PM, Pavel Begunkov wrote: > *lost the cover-letter, but here we go* > > The main idea is to optimise code like the following by directly > copying sqe flags: > > if (sqe_flags & IOSQE_IO_HARDLINK) > req->flags |= REQ_F_HARDLINK; > > The first patch is a minor cleanup, and the second one do the > trick. No functional changes. > > The other thing to consider is whether to use such flags as > REQ_F_LINK = IOSQE_IO_LINK, or directly use IOSQE_IO_LINK instead.
I think we should keep the names separate. I think it looks fine, though I do wish that we could just have both in an enum and not have to do weird naming. We sometimes do:
enum { __REQ_F_FOO };
#define REQ_F_FOO (1U << __REQ_F_FOO)
and with that we could have things Just Work in terms of numbering, if we keep the overlapped values at the start. Would need IOSQE_* to also use an enum, ala:
enum { __IOSQE_FIXED_FILE, __IOSQE_IO_DRAIN, ... };
and then do
#define IOSQE_FIXED_FILE (1U << __IOSQE_FIXED_FILE)
and have the __REQ enum start with
enum { __REQ_F_FIXED_FILE = __IOSQE_FIXED_FILE, __REQ_F_IO_DRAIN = __IOSQE_IO_DRAIN, ... __REQ_F_LINK_NEXT, __REQ_F_FAIL_LINK, ... };
-- Jens Axboe
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