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[31.46.244.27]) by smtp.gmail.com with ESMTPSA id z14-20020a5d4c8e000000b0021e4829d359sm16071633wrs.39.2022.09.07.00.30.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 07 Sep 2022 00:30:20 -0700 (PDT) Sender: Ingo Molnar Date: Wed, 7 Sep 2022 09:30:18 +0200 From: Ingo Molnar To: Peter Zijlstra Cc: rjw@rjwysocki.net, oleg@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, mgorman@suse.de, ebiederm@xmission.com, bigeasy@linutronix.de, Will Deacon , linux-kernel@vger.kernel.org, tj@kernel.org, linux-pm@vger.kernel.org Subject: Re: [PATCH v3 6/6] freezer,sched: Rewrite core freezer logic Message-ID: References: <20220822111816.760285417@infradead.org> <20220822114649.055452969@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org * Peter Zijlstra wrote: > On Sun, Sep 04, 2022 at 12:09:37PM +0200, Ingo Molnar wrote: > > > BTW., we should probably mark/document all PF_ holes with a PF__RESERVED > > kind of scheme? Something simple, like: > > > > #define PF_NPROC_EXCEEDED 0x00001000 /* set_user() noticed that RLIMIT_NPROC was exceeded */ > > #define PF_USED_MATH 0x00002000 /* If unset the fpu must be initialized before use */ > > + #define PF__RESERVED_04000 0x00004000 /* Unused */ > > #define PF_NOFREEZE 0x00008000 /* This thread should not be frozen */ > > + #define PF__RESERVED_10000 0x00010000 /* Unused */ > > #define PF_KSWAPD 0x00020000 /* I am kswapd */ > > #define PF_MEMALLOC_NOFS 0x00040000 /* All allocation requests will inherit GFP_NOFS */ > > #define PF_MEMALLOC_NOIO 0x00080000 /* All allocation requests will inherit GFP_NOIO */ > > > How's this then, it immediately shows how holey it is :-) > > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -1722,7 +1722,9 @@ extern struct pid *cad_pid; > #define PF_MEMALLOC 0x00000800 /* Allocating memory */ > #define PF_NPROC_EXCEEDED 0x00001000 /* set_user() noticed that RLIMIT_NPROC was exceeded */ > #define PF_USED_MATH 0x00002000 /* If unset the fpu must be initialized before use */ > +#define PF__HOLE__00004000 0x00004000 /* A HOLE */ > #define PF_NOFREEZE 0x00008000 /* This thread should not be frozen */ > +#define PF__HOLE__00010000 0x00010000 /* A HOLE */ > #define PF_KSWAPD 0x00020000 /* I am kswapd */ > #define PF_MEMALLOC_NOFS 0x00040000 /* All allocation requests will inherit GFP_NOFS */ > #define PF_MEMALLOC_NOIO 0x00080000 /* All allocation requests will inherit GFP_NOIO */ > @@ -1730,9 +1732,14 @@ extern struct pid *cad_pid; > * I am cleaning dirty pages from some other bdi. */ > #define PF_KTHREAD 0x00200000 /* I am a kernel thread */ > #define PF_RANDOMIZE 0x00400000 /* Randomize virtual address space */ > +#define PF__HOLE__00800000 0x00800000 /* A HOLE */ > +#define PF__HOLE__01000000 0x01000000 /* A HOLE */ > +#define PF__HOLE__02000000 0x02000000 /* A HOLE */ > #define PF_NO_SETAFFINITY 0x04000000 /* Userland is not allowed to meddle with cpus_mask */ > #define PF_MCE_EARLY 0x08000000 /* Early kill for mce process policy */ > #define PF_MEMALLOC_PIN 0x10000000 /* Allocation context constrained to zones which allow long term pinning. */ > +#define PF__HOLE__20000000 0x20000000 /* A HOLE */ > +#define PF__HOLE__40000000 0x40000000 /* A HOLE */ > #define PF_SUSPEND_TASK 0x80000000 /* This thread called freeze_processes() and should not be frozen */ LGTM - OTOH this looks quite a bit more cluttery than I imagined it in my head. :-/ So I'd leave out the comment part at minimum. With that: Reviewed-by: Ingo Molnar Thanks, Ingo