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x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: E4CD640021 X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: gu6kxkw7xnd9dwf7jys5u1tfh78yyxz5 X-HE-Tag: 1694474170-906382 X-HE-Meta: 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 GM4rUYWt OqdM5idYwhaJ4Bp1cDBSSCkGZmN+1n3pqcR7KHeq8nOnI23UiEBHn34/F9T/uhT/0e/qzcyheGM+y8nIq+vB5Gmuk05BaIsyDGTTOQAfJ23caxsymOujhSXNZBUGOh5wCz6p58ZtMPp2d9XICG9Yjh+vuvghfZF6N7M8Av+mdN3eBtyBZ65IclmhdqAB1Qh+rvJfDicwurRtZkq67QyOiw1OaPgGJg3UIF3bOrXcOzuL1nar4DWjBnq/87nL+X9eVrHZebdF/hKR/bdaWV3SEUOWCI/7WisqXPBJoHw+IEs/DKJgGLQ10Q+agcrqYnH4SIRev/dO5S9EMtxTPVVsct6vgTXLqGbtenBqzcC+6HyiWj1CklmlTrEjo943pyvpqHvrGP1a/xhbk/xOfFtyG+B+4+eEx11vqERoDpJnlf2cSvtA= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, 11 Sep 2023 16:10:31 -0700 Ankur Arora wrote: > An even crazier version of that idea would be to have > preempt_disable/enable() demarcate regions, and the compiler putting all > of the preemption disabled region out-of-line to a special section. > Seems to me, that then we could do away to preempt_enable/disable()? > (Ignoring the preempt_count used in hardirq etc.) > I thought about this too, but wasn't sure if it would be easier or harder to implement. This would still require the duplicate functions (which I guess would be the most difficult part). > This would allow preemption always, unless executing in the > preemption-disabled section. > > Though I don't have any intuition for how much extra call overhead this > would add. I don't think this version would have as high of an overhead. You would get a direct jump (which isn't bad as all speculation knows exactly where to look), and it would improve the look up. No table, just a simple range check. -- Steve