b0876afdff
Commentary from Chris Wilson's original version: > I was looking at some wait_for() timeouts on a slow system, with lots of > debug enabled (KASAN, lockdep, mmio_debug). Thinking that we were > mishandling the timeout, I tried to ensure that we loop at least once > after first testing COND. However, the double test of COND either side > of the timeout check makes that unlikely. But we can do an equivalent > loop, that keeps the COND check after testing for timeout (required so > that we are not preempted between testing COND and then testing for a > timeout) without expanding COND twice. > > The advantage of only expanding COND once is a dramatic reduction in > code size: > > text data bss dec hex > 1308733 5184 1152 1315069 1410fd before > 1305341 5184 1152 1311677 1403bd after but it turned out that due to a missing iniitialiser, gcc had "gone wild trimming undefined code" :( This version acheives a rather more modest (but still worthwhile) gain of ~550 bytes. Signed-off-by: Dave Gordon <david.s.gordon@intel.com> Original-idea-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Zanoni, Paulo R <paulo.r.zanoni@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1473855033-26980-1-git-send-email-david.s.gordon@intel.com Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> |
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