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Date:      Thu, 22 Mar 2018 15:42:41 -1000 (HST)
From:      Jeff Roberson <jroberson@jroberson.net>
To:        Cy Schubert <Cy.Schubert@cschubert.com>
Cc:        Justin Hibbits <jrh29@alumni.cwru.edu>, Jeff Roberson <jeff@freebsd.org>,  src-committers <src-committers@freebsd.org>, svn-src-all@freebsd.org,  svn-src-head@freebsd.org
Subject:   Re: svn commit: r331369 - head/sys/vm
Message-ID:  <alpine.BSF.2.21.1803221541590.2307@desktop>
In-Reply-To: <201803230059.w2N0x2fw077291@slippy.cwsent.com>
References:  <201803230059.w2N0x2fw077291@slippy.cwsent.com>

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On Thu, 22 Mar 2018, Cy Schubert wrote:

> It broke i386 too.

I believe I'm not able to reproduce this because it is a result of changes 
in kernel config.  I can not reproduce it so I can't verify the fix. 
Since you can, would you mind committing?  I see no problem with the diff 
below.

Thanks,
Jeff

>
> Index: sys/vm/vm_reserv.c
> ===================================================================
> --- sys/vm/vm_reserv.c	(revision 331399)
> +++ sys/vm/vm_reserv.c	(working copy)
> @@ -45,8 +45,6 @@
>
> #include <sys/param.h>
> #include <sys/kernel.h>
> -#include <sys/counter.h>
> -#include <sys/ktr.h>
> #include <sys/lock.h>
> #include <sys/malloc.h>
> #include <sys/mutex.h>
> @@ -55,6 +53,8 @@
> #include <sys/sbuf.h>
> #include <sys/sysctl.h>
> #include <sys/systm.h>
> +#include <sys/counter.h>
> +#include <sys/ktr.h>
> #include <sys/vmmeter.h>
> #include <sys/smp.h>
>
> This is because sys/i386/include/machine.h uses critical_enter() and
> critical_exit() which are defined in sys/systm.h.
>
> It built nicely on my amd64's though.
>
> ~cy
>
> In message <alpine.BSF.2.21.1803221451420.2307@desktop>, Jeff Roberson
> writes:
>> Thank you, working on it.  I had done a make universe before getting
>> review feedback.
>>
>> Jeff
>>
>> On Thu, 22 Mar 2018, Justin Hibbits wrote:
>>
>>> This broke gcc builds.
>>>
>>> On Thu, Mar 22, 2018 at 2:21 PM, Jeff Roberson <jeff@freebsd.org> wrote:
>>>> Author: jeff
>>>> Date: Thu Mar 22 19:21:11 2018
>>>> New Revision: 331369
>>>> URL: https://svnweb.freebsd.org/changeset/base/331369
>>>>
>>>> Log:
>>>>   Lock reservations with a dedicated lock in each reservation.  Protect th
>> e
>>>>   vmd_free_count with atomics.
>>>>
>>>>   This allows us to allocate and free from reservations without the free l
>> ock
>>>>   except where a superpage is allocated from the physical layer, which is
>>>>   roughly 1/512 of the operations on amd64.
>>>>
>>>>   Use the counter api to eliminate cache conention on counters.
>>>>
>>>>   Reviewed by:  markj
>>>>   Tested by:    pho
>>>>   Sponsored by: Netflix, Dell/EMC Isilon
>>>>   Differential Revision:        https://reviews.freebsd.org/D14707
>>>>
>>>> Modified:
>>>>   head/sys/vm/vm_page.c
>>>>   head/sys/vm/vm_pagequeue.h
>>>>   head/sys/vm/vm_reserv.c
>>>>   head/sys/vm/vm_reserv.h
>>>>
>>>> Modified: head/sys/vm/vm_page.c
>>>> ==========================================================================
>> ====
>>>> --- head/sys/vm/vm_page.c       Thu Mar 22 19:11:43 2018        (r331368)
>>>> +++ head/sys/vm/vm_page.c       Thu Mar 22 19:21:11 2018        (r331369)
>>>> @@ -177,7 +177,6 @@ static uma_zone_t fakepg_zone;
>>>>  static void vm_page_alloc_check(vm_page_t m);
>>>>  static void vm_page_clear_dirty_mask(vm_page_t m, vm_page_bits_t pagebits
>> );
>>>>  static void vm_page_enqueue(uint8_t queue, vm_page_t m);
>>>> -static void vm_page_free_phys(struct vm_domain *vmd, vm_page_t m);
>>>>  static void vm_page_init(void *dummy);
>>>>  static int vm_page_insert_after(vm_page_t m, vm_object_t object,
>>>>      vm_pindex_t pindex, vm_page_t mpred);
>>>> @@ -1677,10 +1676,10 @@ vm_page_alloc_after(vm_object_t object, vm_pindex_
>> t pi
>>>>   * for the request class and false otherwise.
>>>>   */
>>>>  int
>>>> -vm_domain_available(struct vm_domain *vmd, int req, int npages)
>>>> +vm_domain_allocate(struct vm_domain *vmd, int req, int npages)
>>>>  {
>>>> +       u_int limit, old, new;
>>>>
>>>> -       vm_domain_free_assert_locked(vmd);
>>>>         req = req & VM_ALLOC_CLASS_MASK;
>>>>
>>>>         /*
>>>> @@ -1688,15 +1687,34 @@ vm_domain_available(struct vm_domain *vmd, int req
>> , in
>>>>          */
>>>>         if (curproc == pageproc && req != VM_ALLOC_INTERRUPT)
>>>>                 req = VM_ALLOC_SYSTEM;
>>>> +       if (req == VM_ALLOC_INTERRUPT)
>>>> +               limit = 0;
>>>> +       else if (req == VM_ALLOC_SYSTEM)
>>>> +               limit = vmd->vmd_interrupt_free_min;
>>>> +       else
>>>> +               limit = vmd->vmd_free_reserved;
>>>>
>>>> -       if (vmd->vmd_free_count >= npages + vmd->vmd_free_reserved ||
>>>> -           (req == VM_ALLOC_SYSTEM &&
>>>> -           vmd->vmd_free_count >= npages + vmd->vmd_interrupt_free_min) |
>> |
>>>> -           (req == VM_ALLOC_INTERRUPT &&
>>>> -           vmd->vmd_free_count >= npages))
>>>> -               return (1);
>>>> +       /*
>>>> +        * Attempt to reserve the pages.  Fail if we're below the limit.
>>>> +        */
>>>> +       limit += npages;
>>>> +       old = vmd->vmd_free_count;
>>>> +       do {
>>>> +               if (old < limit)
>>>> +                       return (0);
>>>> +               new = old - npages;
>>>> +       } while (atomic_fcmpset_int(&vmd->vmd_free_count, &old, new) == 0)
>> ;
>>>>
>>>> -       return (0);
>>>> +       /* Wake the page daemon if we've crossed the threshold. */
>>>> +       if (vm_paging_needed(vmd, new) && !vm_paging_needed(vmd, old))
>>>> +               pagedaemon_wakeup(vmd->vmd_domain);
>>>> +
>>>> +       /* Only update bitsets on transitions. */
>>>> +       if ((old >= vmd->vmd_free_min && new < vmd->vmd_free_min) ||
>>>> +           (old >= vmd->vmd_free_severe && new < vmd->vmd_free_severe))
>>>> +               vm_domain_set(vmd);
>>>> +
>>>> +       return (1);
>>>>  }
>>>>
>>>>  vm_page_t
>>>> @@ -1723,44 +1741,34 @@ vm_page_alloc_domain_after(vm_object_t object, vm_
>> pind
>>>>  again:
>>>>         m = NULL;
>>>>  #if VM_NRESERVLEVEL > 0
>>>> +       /*
>>>> +        * Can we allocate the page from a reservation?
>>>> +        */
>>>>         if (vm_object_reserv(object) &&
>>>> -           (m = vm_reserv_extend(req, object, pindex, domain, mpred))
>>>> -           != NULL) {
>>>> +           ((m = vm_reserv_extend(req, object, pindex, domain, mpred)) !=
>>  NULL ||
>>>> +           (m = vm_reserv_alloc_page(req, object, pindex, domain, mpred))
>>  != NULL)) {
>>>>                 domain = vm_phys_domain(m);
>>>>                 vmd = VM_DOMAIN(domain);
>>>>                 goto found;
>>>>         }
>>>>  #endif
>>>>         vmd = VM_DOMAIN(domain);
>>>> -       vm_domain_free_lock(vmd);
>>>> -       if (vm_domain_available(vmd, req, 1)) {
>>>> +       if (vm_domain_allocate(vmd, req, 1)) {
>>>>                 /*
>>>> -                * Can we allocate the page from a reservation?
>>>> +                * If not, allocate it from the free page queues.
>>>>                  */
>>>> +               vm_domain_free_lock(vmd);
>>>> +               m = vm_phys_alloc_pages(domain, object != NULL ?
>>>> +                   VM_FREEPOOL_DEFAULT : VM_FREEPOOL_DIRECT, 0);
>>>> +               vm_domain_free_unlock(vmd);
>>>> +               if (m == NULL) {
>>>> +                       vm_domain_freecnt_inc(vmd, 1);
>>>>  #if VM_NRESERVLEVEL > 0
>>>> -               if (!vm_object_reserv(object) ||
>>>> -                   (m = vm_reserv_alloc_page(object, pindex,
>>>> -                   domain, mpred)) == NULL)
>>>> +                       if (vm_reserv_reclaim_inactive(domain))
>>>> +                               goto again;
>>>>  #endif
>>>> -               {
>>>> -                       /*
>>>> -                        * If not, allocate it from the free page queues.
>>>> -                        */
>>>> -                       m = vm_phys_alloc_pages(domain, object != NULL ?
>>>> -                           VM_FREEPOOL_DEFAULT : VM_FREEPOOL_DIRECT, 0);
>>>> -#if VM_NRESERVLEVEL > 0
>>>> -                       if (m == NULL && vm_reserv_reclaim_inactive(domain
>> )) {
>>>> -                               m = vm_phys_alloc_pages(domain,
>>>> -                                   object != NULL ?
>>>> -                                   VM_FREEPOOL_DEFAULT : VM_FREEPOOL_DIRE
>> CT,
>>>> -                                   0);
>>>> -                       }
>>>> -#endif
>>>>                 }
>>>>         }
>>>> -       if (m != NULL)
>>>> -               vm_domain_freecnt_dec(vmd, 1);
>>>> -       vm_domain_free_unlock(vmd);
>>>>         if (m == NULL) {
>>>>                 /*
>>>>                  * Not allocatable, give up.
>>>> @@ -1775,9 +1783,7 @@ again:
>>>>          */
>>>>         KASSERT(m != NULL, ("missing page"));
>>>>
>>>> -#if VM_NRESERVLEVEL > 0
>>>>  found:
>>>> -#endif
>>>
>>> 'found' is now declared, but unused on powerpc64.
>>>
>>> - Justin
>>>
>>
>
> -- 
> Cheers,
> Cy Schubert <Cy.Schubert@cschubert.com>
> FreeBSD UNIX:  <cy@FreeBSD.org>   Web:  http://www.FreeBSD.org
>
> 	The need of the many outweighs the greed of the few.
>
>



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