Re: [RFC PATCH v2 1/3] meminfo_extra: introduce meminfo extra
On Sun, Mar 29, 2020 at 09:23:04AM +0200, Greg KH wrote: > On Sun, Mar 29, 2020 at 10:19:07AM +0300, Leon Romanovsky wrote: > > On Tue, Mar 24, 2020 at 09:53:16PM +0900, Jaewon Kim wrote: > > > > > > > > > On 2020년 03월 24일 20:46, Greg KH wrote: > > > > On Tue, Mar 24, 2020 at 08:37:38PM +0900, Jaewon Kim wrote: > > > >> > > > >> On 2020년 03월 24일 19:11, Greg KH wrote: > > > >>> On Tue, Mar 24, 2020 at 06:11:17PM +0900, Jaewon Kim wrote: > > > >>>> On 2020년 03월 23일 18:53, Greg KH wrote: > > > >>>>>> +int register_meminfo_extra(atomic_long_t *val, int shift, const > > > >>>>>> char *name) > > > >>>>>> +{ > > > >>>>>> + struct meminfo_extra *meminfo, *memtemp; > > > >>>>>> + int len; > > > >>>>>> + int error = 0; > > > >>>>>> + > > > >>>>>> + meminfo = kzalloc(sizeof(*meminfo), GFP_KERNEL); > > > >>>>>> + if (!meminfo) { > > > >>>>>> + error = -ENOMEM; > > > >>>>>> + goto out; > > > >>>>>> + } > > > >>>>>> + > > > >>>>>> + meminfo->val = val; > > > >>>>>> + meminfo->shift_for_page = shift; > > > >>>>>> + strncpy(meminfo->name, name, NAME_SIZE); > > > >>>>>> + len = strlen(meminfo->name); > > > >>>>>> + meminfo->name[len] = ':'; > > > >>>>>> + strncpy(meminfo->name_pad, meminfo->name, NAME_BUF_SIZE); > > > >>>>>> + while (++len < NAME_BUF_SIZE - 1) > > > >>>>>> + meminfo->name_pad[len] = ' '; > > > >>>>>> + > > > >>>>>> + spin_lock(_lock); > > > >>>>>> + list_for_each_entry_rcu(memtemp, _head, list) { > > > >>>>>> + if (memtemp->val == val) { > > > >>>>>> + error = -EINVAL; > > > >>>>>> + break; > > > >>>>>> + } > > > >>>>>> + } > > > >>>>>> + if (!error) > > > >>>>>> + list_add_tail_rcu(>list, _head); > > > >>>>>> + spin_unlock(_lock); > > > >>>>> If you have a lock, why are you needing rcu? > > > >>>> I think _rcu should be removed out of list_for_each_entry_rcu. > > > >>>> But I'm confused about what you meant. > > > >>>> I used rcu_read_lock on __meminfo_extra, > > > >>>> and I think spin_lock is also needed for addition and deletion to > > > >>>> handle multiple modifiers. > > > >>> If that's the case, then that's fine, it just didn't seem like that > > > >>> was > > > >>> needed. Or I might have been reading your rcu logic incorrectly... > > > >>> > > > >>>>>> + if (error) > > > >>>>>> + kfree(meminfo); > > > >>>>>> +out: > > > >>>>>> + > > > >>>>>> + return error; > > > >>>>>> +} > > > >>>>>> +EXPORT_SYMBOL(register_meminfo_extra); > > > >>>>> EXPORT_SYMBOL_GPL()? I have to ask :) > > > >>>> I can use EXPORT_SYMBOL_GPL. > > > >>>>> thanks, > > > >>>>> > > > >>>>> greg k-h > > > >>>>> > > > >>>>> > > > >>>> Hello > > > >>>> Thank you for your comment. > > > >>>> > > > >>>> By the way there was not resolved discussion on v1 patch as I > > > >>>> mentioned on cover page. > > > >>>> I'd like to hear your opinion on this /proc/meminfo_extra node. > > > >>> I think it is the propagation of an old and obsolete interface that > > > >>> you > > > >>> will have to support for the next 20+ years and yet not actually be > > > >>> useful :) > > > >>> > > > >>>> Do you think this is meaningful or cannot co-exist with other
Re: [RFC PATCH v2 1/3] meminfo_extra: introduce meminfo extra
On Tue, Mar 24, 2020 at 09:53:16PM +0900, Jaewon Kim wrote: > > > On 2020년 03월 24일 20:46, Greg KH wrote: > > On Tue, Mar 24, 2020 at 08:37:38PM +0900, Jaewon Kim wrote: > >> > >> On 2020년 03월 24일 19:11, Greg KH wrote: > >>> On Tue, Mar 24, 2020 at 06:11:17PM +0900, Jaewon Kim wrote: > >>>> On 2020년 03월 23일 18:53, Greg KH wrote: > >>>>>> +int register_meminfo_extra(atomic_long_t *val, int shift, const char > >>>>>> *name) > >>>>>> +{ > >>>>>> + struct meminfo_extra *meminfo, *memtemp; > >>>>>> + int len; > >>>>>> + int error = 0; > >>>>>> + > >>>>>> + meminfo = kzalloc(sizeof(*meminfo), GFP_KERNEL); > >>>>>> + if (!meminfo) { > >>>>>> + error = -ENOMEM; > >>>>>> + goto out; > >>>>>> + } > >>>>>> + > >>>>>> + meminfo->val = val; > >>>>>> + meminfo->shift_for_page = shift; > >>>>>> + strncpy(meminfo->name, name, NAME_SIZE); > >>>>>> + len = strlen(meminfo->name); > >>>>>> + meminfo->name[len] = ':'; > >>>>>> + strncpy(meminfo->name_pad, meminfo->name, NAME_BUF_SIZE); > >>>>>> + while (++len < NAME_BUF_SIZE - 1) > >>>>>> + meminfo->name_pad[len] = ' '; > >>>>>> + > >>>>>> + spin_lock(_lock); > >>>>>> + list_for_each_entry_rcu(memtemp, _head, list) { > >>>>>> + if (memtemp->val == val) { > >>>>>> + error = -EINVAL; > >>>>>> + break; > >>>>>> + } > >>>>>> + } > >>>>>> + if (!error) > >>>>>> + list_add_tail_rcu(>list, _head); > >>>>>> + spin_unlock(_lock); > >>>>> If you have a lock, why are you needing rcu? > >>>> I think _rcu should be removed out of list_for_each_entry_rcu. > >>>> But I'm confused about what you meant. > >>>> I used rcu_read_lock on __meminfo_extra, > >>>> and I think spin_lock is also needed for addition and deletion to handle > >>>> multiple modifiers. > >>> If that's the case, then that's fine, it just didn't seem like that was > >>> needed. Or I might have been reading your rcu logic incorrectly... > >>> > >>>>>> + if (error) > >>>>>> + kfree(meminfo); > >>>>>> +out: > >>>>>> + > >>>>>> + return error; > >>>>>> +} > >>>>>> +EXPORT_SYMBOL(register_meminfo_extra); > >>>>> EXPORT_SYMBOL_GPL()? I have to ask :) > >>>> I can use EXPORT_SYMBOL_GPL. > >>>>> thanks, > >>>>> > >>>>> greg k-h > >>>>> > >>>>> > >>>> Hello > >>>> Thank you for your comment. > >>>> > >>>> By the way there was not resolved discussion on v1 patch as I mentioned > >>>> on cover page. > >>>> I'd like to hear your opinion on this /proc/meminfo_extra node. > >>> I think it is the propagation of an old and obsolete interface that you > >>> will have to support for the next 20+ years and yet not actually be > >>> useful :) > >>> > >>>> Do you think this is meaningful or cannot co-exist with other future > >>>> sysfs based API. > >>> What sysfs-based API? > >> Please refer to mail thread on v1 patch set - > >> https://protect2.fireeye.com/url?k=16e3accc-4b2f6548-16e22783-0cc47aa8f5ba-935fe828ac2f6656=https://lkml.org/lkml/fancy/2020/3/10/2102 > >> especially discussion with Leon Romanovsky on > >> https://protect2.fireeye.com/url?k=74208ed9-29ec475d-74210596-0cc47aa8f5ba-0bd4ef48931fec95=https://lkml.org/lkml/fancy/2020/3/16/140 > > I really do not understand what you are referring to here, sorry. I do > > not see any sysfs-based code in that thread. > Sorry. I also did not see actual code. > Hello Leon Romanovsky, could you elaborate your plan regarding sysfs stuff? Sorry for being late, I wasn't in "TO:", so missed the whole discussion. Greg, We need the exposed information for the memory optimizations (debug, not production) of our high speed NICs. Our devices (mlx5) allocates a lot of memory, so optimization there can help us to scale in SRIOV mode easier and be less constraint by the memory. I want to emphasize that I don't like idea of extending /proc/* interface because it is going to be painful to grep on large machines with many devices. And I don't like the idea that every driver will need to register into this interface, because it will be abused almost immediately. My proposal was to create new sysfs file by driver/core and put all information automatically there, for example, it can be /sys/devices/pci:00/:00:0c.0/meminfo ^^^ Thanks ___ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
Re: [PATCH v4 7/8] linux/log2.h: Fix 64bit calculations in roundup/down_pow_two()
On Tue, Dec 03, 2019 at 12:47:40PM +0100, Nicolas Saenz Julienne wrote: > Some users need to make sure their rounding function accepts and returns > 64bit long variables regardless of the architecture. Sadly > roundup/rounddown_pow_two() takes and returns unsigned longs. It turns > out ilog2() already handles 32/64bit calculations properly, and being > the building block to the round functions we can rework them as a > wrapper around it. > > Suggested-by: Robin Murphy > Signed-off-by: Nicolas Saenz Julienne > --- > drivers/clk/clk-divider.c| 8 ++-- > drivers/clk/sunxi/clk-sunxi.c| 2 +- > drivers/infiniband/hw/hfi1/chip.c| 4 +- > drivers/infiniband/hw/hfi1/init.c| 4 +- > drivers/infiniband/hw/mlx4/srq.c | 2 +- > drivers/infiniband/hw/mthca/mthca_srq.c | 2 +- > drivers/infiniband/sw/rxe/rxe_qp.c | 4 +- Thanks, for infiniband. Reviewed-by: Leon Romanovsky ___ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec