On Mon, Mar 14, 2016 at 5:36 AM, Denys Vlasenko <[email protected]> wrote: > On Sun, Mar 13, 2016 at 10:00 PM, Denys Vlasenko <[email protected]> wrote: >> This function compiles to 2684 bytes, 2 callsites >> >> text data bss dec hex filename >> 9655 16 0 9671 25c7 direct-io.o.before2 >> 9559 16 0 9575 2567 direct-io.o > > Al, you undoubtedly noticed the discrepancy between > "save 2684 bytes" claim in the commit description > and the above data, which shows no such thing. > > Sorry, I was too quick to send the mail to notice it :( > > Further investigation had shown that it's my particular version of gcc > deciding to deinline the function even before the patch. > Other version of gcc, on a different machine was running > large inlining search script, did not do that, and saw the 2684 bytes > of savings. > > tl;dr: the patch is correct, my "size" printout wasn't.
Not sure the patch is correct, please see the commit for do_blockdev_direct_IO(): * NOTE: if you pass "sdio" to anything by pointer make sure that function * is always inlined. Otherwise gcc is unable to split the structure into * individual fields and will generate much worse code. This is important * for the whole file. thanks, Ming Lei
