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charset=us-ascii Content-Disposition: inline In-Reply-To: <87sf7n6ea4.fsf@oracle.com> X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 61F3340012 X-Stat-Signature: fembwqkfnciu7yrnfbchd18xudry5tih X-Rspam-User: X-HE-Tag: 1694250688-579997 X-HE-Meta: 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 ylJn3SB4 KIFVGIXZRYJPA5ejGpRD0MJKpJdXDVOtDVNojrDBGhsObP3UK2v6a5FLLFTGGCXqT2V51BWANcIoZ7Y+TGC/wZzBcCuVW3SNtEsiFNkf2QQ+kz6W3xAn10yH7rnEKVrxe6FmiAB3XlUK1WYPDdJ7A/r5bwxwz1XxTadwSp0hJ7uqzCi3kmR1IsRzNfQ== 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 Fri, Sep 08, 2023 at 11:39:47PM -0700, Ankur Arora wrote: > Yeah, exactly. Though, not even a single context level, but a flag > attached to a single context at the process level only. Using > preempt_count() == 0 as the preemption boundary. > > However, this has a problem with the PREEMPT_COUNT=n case because that > doesn't have a preemption boundary. So, with a little sleep, the nested exception/interrupt case should be good, irqenrty_enter() / irqentry_nmi_enter() unconditionally increment preempt_count with HARDIRQ_OFFSET / NMI_OFFSET. So while regular preempt_{dis,en}able() will turn into a NOP, the entry code *will* continue to increment preempt_count.