Date: Mon, 07 Oct 2019 09:12:31 -0700 From: Cy Schubert <Cy.Schubert@cschubert.com> To: Mateusz Guzik <mjguzik@gmail.com> Cc: Cy Schubert <Cy.Schubert@cschubert.com>, src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r353149 - head/sys/amd64/amd64 Message-ID: <201910071612.x97GCVx3003714@slippy.cwsent.com> In-Reply-To: <CAGudoHFbuUgCrBa1JS6S5ynB_obpwBJdyRP66bd-WuhHO8ZP7A@mail.gmail.com> References: <201910062213.x96MDZv3085523@repo.freebsd.org> <201910070406.x9746N0U009068@slippy.cwsent.com> <201910070419.x974JOkQ020574@slippy.cwsent.com> <CAGudoHFbuUgCrBa1JS6S5ynB_obpwBJdyRP66bd-WuhHO8ZP7A@mail.gmail.com>
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In message <CAGudoHFbuUgCrBa1JS6S5ynB_obpwBJdyRP66bd-WuhHO8ZP7A@mail.gmail.c
om>
, Mateusz Guzik writes:
> Can you show:
>
> sysctl vm.phys_segso
vm.phys_segs:
SEGMENT 0:
start: 0x10000
end: 0x9d000
domain: 0
free list: 0xffffffff80f31070
SEGMENT 1:
start: 0x100000
end: 0x1000000
domain: 0
free list: 0xffffffff80f31070
SEGMENT 2:
start: 0x1000000
end: 0x1ca4000
domain: 0
free list: 0xffffffff80f30e00
SEGMENT 3:
start: 0x1cb3000
end: 0x1ce3000
domain: 0
free list: 0xffffffff80f30e00
SEGMENT 4:
start: 0x1f00000
end: 0x20000000
domain: 0
free list: 0xffffffff80f30e00
SEGMENT 5:
start: 0x20200000
end: 0x40000000
domain: 0
free list: 0xffffffff80f30e00
SEGMENT 6:
start: 0x40203000
end: 0xd4993000
domain: 0
free list: 0xffffffff80f30e00
SEGMENT 7:
start: 0xd6fff000
end: 0xd7000000
domain: 0
free list: 0xffffffff80f30e00
SEGMENT 8:
start: 0x100001000
end: 0x211d4d000
domain: 0
free list: 0xffffffff80f30e00
SEGMENT 9:
start: 0x21fc00000
end: 0x21fd44000
domain: 0
free list: 0xffffffff80f30e00
>
> and from the crashdump:
> p pv_table
$1 = (struct pmap_large_md_page *) 0xfffffe000e000000
kgdb) p *pv_table
$1 = {pv_lock = {lock_object = {lo_name = 0xffffffff80b0a9ce "pmap pv
list",
lo_flags = 623050752, lo_data = 0, lo_witness = 0x800000000201f163},
rw_lock = 1}, pv_page = {pv_list = {tqh_first = 0x0,
tqh_last = 0xfffffe000e000020}, pv_gen = 0, pat_mode = 0},
pv_invl_gen = 0}
(kgdb)
--
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.
>
> On 10/7/19, Cy Schubert <Cy.Schubert@cschubert.com> wrote:
> > In message <201910070406.x9746N0U009068@slippy.cwsent.com>, Cy Schubert
> > writes:
> >> In message <201910062213.x96MDZv3085523@repo.freebsd.org>, Mateusz Guzik
> >> writes
> >> :
> >> > Author: mjg
> >> > Date: Sun Oct 6 22:13:35 2019
> >> > New Revision: 353149
> >> > URL: https://svnweb.freebsd.org/changeset/base/353149
> >> >
> >> > Log:
> >> > amd64 pmap: implement per-superpage locks
> >> >
> >> > The current 256-lock sized array is a problem in the following ways:
> >> > - it's way too small
> >> > - there are 2 locks per cacheline
> >> > - it is not NUMA-aware
> >> >
> >> > Solve these issues by introducing per-superpage locks backed by pages
> >> > allocated from respective domains.
> >> >
> >> > This significantly reduces contention e.g. during poudriere -j 104.
> >> > See the review for results.
> >> >
> >> > Reviewed by: kib
> >> > Discussed with: jeff
> >> > Sponsored by: The FreeBSD Foundation
> >> > Differential Revision: https://reviews.freebsd.org/D21833
> >> >
> >> > Modified:
> >> > head/sys/amd64/amd64/pmap.c
> >> >
> >> > Modified: head/sys/amd64/amd64/pmap.c
> >> > ========================================================================
> ===
> >> ==
> >> > =
> >> > --- head/sys/amd64/amd64/pmap.c Sun Oct 6 20:36:25 2019 (r35314
> >> > 8)
> >> > +++ head/sys/amd64/amd64/pmap.c Sun Oct 6 22:13:35 2019 (r35314
> >> > 9)
> >> > @@ -316,13 +316,25 @@ pmap_pku_mask_bit(pmap_t pmap)
> >> > #define PV_STAT(x) do { } while (0)
> >> > #endif
> >> >
> >> > -#define pa_index(pa) ((pa) >> PDRSHIFT)
> >> > +#undef pa_index
> >> > +#define pa_index(pa) ({ \
> >> > + KASSERT((pa) <= vm_phys_segs[vm_phys_nsegs - 1].end, \
> >> > + ("address %lx beyond the last segment", (pa))); \
> >> > + (pa) >> PDRSHIFT; \
> >> > +})
> >> > +#if VM_NRESERVLEVEL > 0
> >> > +#define pa_to_pmdp(pa) (&pv_table[pa_index(pa)])
> >> > +#define pa_to_pvh(pa) (&(pa_to_pmdp(pa)->pv_page))
> >> > +#define PHYS_TO_PV_LIST_LOCK(pa) \
> >> > + (&(pa_to_pmdp(pa)->pv_lock))
> >> > +#else
> >> > #define pa_to_pvh(pa) (&pv_table[pa_index(pa)])
> >> >
> >> > #define NPV_LIST_LOCKS MAXCPU
> >> >
> >> > #define PHYS_TO_PV_LIST_LOCK(pa) \
> >> > (&pv_list_locks[pa_index(pa) % NPV_LIST_LOCKS])
> >> > +#endif
> >> >
> >> > #define CHANGE_PV_LIST_LOCK_TO_PHYS(lockp, pa) do { \
> >> > struct rwlock **_lockp = (lockp); \
> >> > @@ -400,14 +412,22 @@ static int pmap_initialized;
> >> >
> >> > /*
> >> > * Data for the pv entry allocation mechanism.
> >> > - * Updates to pv_invl_gen are protected by the pv_list_locks[]
> >> > - * elements, but reads are not.
> >> > + * Updates to pv_invl_gen are protected by the pv list lock but reads
> >> > are
> >> no
> >> > t.
> >> > */
> >> > static TAILQ_HEAD(pch, pv_chunk) pv_chunks =
> >> > TAILQ_HEAD_INITIALIZER(pv_chu
> >> nk
> >> > s);
> >> > static struct mtx __exclusive_cache_line pv_chunks_mutex;
> >> > +#if VM_NRESERVLEVEL > 0
> >> > +struct pmap_large_md_page {
> >> > + struct rwlock pv_lock;
> >> > + struct md_page pv_page;
> >> > + u_long pv_invl_gen;
> >> > +};
> >> > +static struct pmap_large_md_page *pv_table;
> >> > +#else
> >> > static struct rwlock __exclusive_cache_line
> >> > pv_list_locks[NPV_LIST_LOCKS];
> >> > static u_long pv_invl_gen[NPV_LIST_LOCKS];
> >> > static struct md_page *pv_table;
> >> > +#endif
> >> > static struct md_page pv_dummy;
> >> >
> >> > /*
> >> > @@ -918,12 +938,21 @@ SYSCTL_LONG(_vm_pmap, OID_AUTO, invl_wait_slow,
> >> > CTLFL
> >> A
> >> > "Number of slow invalidation waits for lockless DI");
> >> > #endif
> >> >
> >> > +#if VM_NRESERVLEVEL > 0
> >> > static u_long *
> >> > pmap_delayed_invl_genp(vm_page_t m)
> >> > {
> >> >
> >> > + return (&pa_to_pmdp(VM_PAGE_TO_PHYS(m))->pv_invl_gen);
> >> > +}
> >> > +#else
> >> > +static u_long *
> >> > +pmap_delayed_invl_genp(vm_page_t m)
> >> > +{
> >> > +
> >> > return (&pv_invl_gen[pa_index(VM_PAGE_TO_PHYS(m)) % NPV_LIST_LO
> CKS]);
> >> > }
> >> > +#endif
> >> >
> >> > static void
> >> > pmap_delayed_invl_callout_func(void *arg __unused)
> >> > @@ -1803,6 +1832,112 @@ pmap_page_init(vm_page_t m)
> >> > m->md.pat_mode = PAT_WRITE_BACK;
> >> > }
> >> >
> >> > +#if VM_NRESERVLEVEL > 0
> >> > +static void
> >> > +pmap_init_pv_table(void)
> >> > +{
> >> > + struct pmap_large_md_page *pvd;
> >> > + vm_size_t s;
> >> > + long start, end, highest, pv_npg;
> >> > + int domain, i, j, pages;
> >> > +
> >> > + /*
> >> > + * We strongly depend on the size being a power of two, so the
> assert
> >> > + * is overzealous. However, should the struct be resized to a
> >> > + * different power of two, the code below needs to be revisited
> .
> >> > + */
> >> > + CTASSERT((sizeof(*pvd) == 64));
> >> > +
> >> > + /*
> >> > + * Calculate the size of the array.
> >> > + */
> >> > + pv_npg = howmany(vm_phys_segs[vm_phys_nsegs - 1].end, NBPDR);
> >> > + s = (vm_size_t)pv_npg * sizeof(struct pmap_large_md_page);
> >> > + s = round_page(s);
> >> > + pv_table = (struct pmap_large_md_page *)kva_alloc(s);
> >> > + if (pv_table == NULL)
> >> > + panic("%s: kva_alloc failed\n", __func__);
> >> > +
> >> > + /*
> >> > + * Iterate physical segments to allocate space for respective p
> ages.
> >> > + */
> >> > + highest = -1;
> >> > + s = 0;
> >> > + for (i = 0; i < vm_phys_nsegs; i++) {
> >> > + start = vm_phys_segs[i].start / NBPDR;
> >> > + end = vm_phys_segs[i].end / NBPDR;
> >> > + domain = vm_phys_segs[i].domain;
> >> > +
> >> > + if (highest >= end)
> >> > + continue;
> >> > +
> >> > + if (start < highest) {
> >> > + start = highest + 1;
> >> > + pvd = &pv_table[start];
> >> > + } else {
> >> > + /*
> >> > + * The lowest address may land somewhere in the
> middle
> >> > + * of our page. Simplify the code by pretending
> it is
> >> > + * at the beginning.
> >> > + */
> >> > + pvd = pa_to_pmdp(vm_phys_segs[i].start);
> >> > + pvd = (struct pmap_large_md_page *)trunc_page(p
> vd);
> >> > + start = pvd - pv_table;
> >> > + }
> >> > +
> >> > + pages = end - start + 1;
> >> > + s = round_page(pages * sizeof(*pvd));
> >> > + highest = start + (s / sizeof(*pvd)) - 1;
> >> > +
> >> > + for (j = 0; j < s; j += PAGE_SIZE) {
> >> > + vm_page_t m = vm_page_alloc_domain(NULL, 0,
> >> > + domain, VM_ALLOC_NORMAL | VM_ALLOC_NOOBJ);
> >> > + if (m == NULL)
> >> > + panic("vm_page_alloc_domain failed for
> %lx\n",
> >> > (vm_offset_t)pvd + j);
> >> > + pmap_qenter((vm_offset_t)pvd + j, &m, 1);
> >> > + }
> >> > +
> >> > + for (j = 0; j < s / sizeof(*pvd); j++) {
> >> > + rw_init_flags(&pvd->pv_lock, "pmap pv list", RW
> _NEW);
> >> > + TAILQ_INIT(&pvd->pv_page.pv_list);
> >> > + pvd->pv_page.pv_gen = 0;
> >> > + pvd->pv_page.pat_mode = 0;
> >> > + pvd->pv_invl_gen = 0;
> >> > + pvd++;
> >> > + }
> >> > + }
> >> > + TAILQ_INIT(&pv_dummy.pv_list);
> >> > +}
> >> > +#else
> >> > +static void
> >> > +pmap_init_pv_table(void)
> >> > +{
> >> > + vm_size_t s;
> >> > + long i, pv_npg;
> >> > +
> >> > + /*
> >> > + * Initialize the pool of pv list locks.
> >> > + */
> >> > + for (i = 0; i < NPV_LIST_LOCKS; i++)
> >> > + rw_init(&pv_list_locks[i], "pmap pv list");
> >> > +
> >> > + /*
> >> > + * Calculate the size of the pv head table for superpages.
> >> > + */
> >> > + pv_npg = howmany(vm_phys_segs[vm_phys_nsegs - 1].end, NBPDR);
> >> > +
> >> > + /*
> >> > + * Allocate memory for the pv head table for superpages.
> >> > + */
> >> > + s = (vm_size_t)pv_npg * sizeof(struct md_page);
> >> > + s = round_page(s);
> >> > + pv_table = (struct md_page *)kmem_malloc(s, M_WAITOK | M_ZERO);
> >> > + for (i = 0; i < pv_npg; i++)
> >> > + TAILQ_INIT(&pv_table[i].pv_list);
> >> > + TAILQ_INIT(&pv_dummy.pv_list);
> >> > +}
> >> > +#endif
> >> > +
> >> > /*
> >> > * Initialize the pmap module.
> >> > * Called by vm_init, to initialize any structures that the pmap
> >> > @@ -1813,8 +1948,7 @@ pmap_init(void)
> >> > {
> >> > struct pmap_preinit_mapping *ppim;
> >> > vm_page_t m, mpte;
> >> > - vm_size_t s;
> >> > - int error, i, pv_npg, ret, skz63;
> >> > + int error, i, ret, skz63;
> >> >
> >> > /* L1TF, reserve page @0 unconditionally */
> >> > vm_page_blacklist_add(0, bootverbose);
> >> > @@ -1902,26 +2036,7 @@ pmap_init(void)
> >> > */
> >> > mtx_init(&pv_chunks_mutex, "pmap pv chunk list", NULL, MTX_DEF)
> ;
> >> >
> >> > - /*
> >> > - * Initialize the pool of pv list locks.
> >> > - */
> >> > - for (i = 0; i < NPV_LIST_LOCKS; i++)
> >> > - rw_init(&pv_list_locks[i], "pmap pv list");
> >> > -
> >> > - /*
> >> > - * Calculate the size of the pv head table for superpages.
> >> > - */
> >> > - pv_npg = howmany(vm_phys_segs[vm_phys_nsegs - 1].end, NBPDR);
> >> > -
> >> > - /*
> >> > - * Allocate memory for the pv head table for superpages.
> >> > - */
> >> > - s = (vm_size_t)(pv_npg * sizeof(struct md_page));
> >> > - s = round_page(s);
> >> > - pv_table = (struct md_page *)kmem_malloc(s, M_WAITOK | M_ZERO);
> >> > - for (i = 0; i < pv_npg; i++)
> >> > - TAILQ_INIT(&pv_table[i].pv_list);
> >> > - TAILQ_INIT(&pv_dummy.pv_list);
> >> > + pmap_init_pv_table();
> >> >
> >> > pmap_initialized = 1;
> >> > for (i = 0; i < PMAP_PREINIT_MAPPING_COUNT; i++) {
> >> >
> >>
> >> This causes a page fault during X (xdm) startup, which loads
> >> drm-current-kmod.
> >>
> >> db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame
> >> 0xfffffe0093e9c260
> >> vpanic() at vpanic+0x19d/frame 0xfffffe0093e9c2b0
> >> panic() at panic+0x43/frame 0xfffffe0093e9c310
> >> vm_fault() at vm_fault+0x2126/frame 0xfffffe0093e9c460
> >> vm_fault_trap() at vm_fault_trap+0x73/frame 0xfffffe0093e9c4b0
> >> trap_pfault() at trap_pfault+0x1b6/frame 0xfffffe0093e9c510
> >> trap() at trap+0x2a1/frame 0xfffffe0093e9c620
> >> calltrap() at calltrap+0x8/frame 0xfffffe0093e9c620
> >> --- trap 0xc, rip = 0xffffffff80a054b1, rsp = 0xfffffe0093e9c6f0, rbp =
> >> 0xfffffe0093e9c7a0 ---
> >> pmap_enter() at pmap_enter+0x861/frame 0xfffffe0093e9c7a0
> >> vm_fault() at vm_fault+0x1c69/frame 0xfffffe0093e9c8f0
> >> vm_fault_trap() at vm_fault_trap+0x73/frame 0xfffffe0093e9c940
> >> trap_pfault() at trap_pfault+0x1b6/frame 0xfffffe0093e9c9a0
> >> trap() at trap+0x438/frame 0xfffffe0093e9cab0
> >> calltrap() at calltrap+0x8/frame 0xfffffe0093e9cab0
> >> --- trap 0xc, rip = 0x30e2a9c3, rsp = 0x7fffffffea50, rbp = 0x7fffffffeaa0
> >>
> >> ---
> >> Uptime: 3m33s
> >> Dumping 945 out of 7974
> >> MB:..2%..11%..21%..31%..41%..51%..61%..72%..82%..92%
> >>
> >> (kgdb) bt
> >> #0 doadump (textdump=1) at pcpu_aux.h:55
> >> #1 0xffffffff8068c5ed in kern_reboot (howto=260)
> >> at /opt/src/svn-current/sys/kern/kern_shutdown.c:479
> >> #2 0xffffffff8068caa9 in vpanic (fmt=<value optimized out>,
> >> ap=<value optimized out>)
> >> at /opt/src/svn-current/sys/kern/kern_shutdown.c:908
> >> #3 0xffffffff8068c8a3 in panic (fmt=<value optimized out>)
> >> at /opt/src/svn-current/sys/kern/kern_shutdown.c:835
> >> #4 0xffffffff8098c966 in vm_fault (map=<value optimized out>,
> >> vaddr=<value optimized out>, fault_type=<value optimized out>,
> >> fault_flags=<value optimized out>, m_hold=<value optimized out>)
> >> at /opt/src/svn-current/sys/vm/vm_fault.c:672
> >> #5 0xffffffff8098a723 in vm_fault_trap (map=0xfffff80002001000,
> >> vaddr=<value optimized out>, fault_type=2 '\002',
> >> fault_flags=<value optimized out>, signo=0x0, ucode=0x0)
> >> at /opt/src/svn-current/sys/vm/vm_fault.c:568
> >> #6 0xffffffff80a18326 in trap_pfault (frame=0xfffffe0093e9c630,
> >> signo=<value optimized out>, ucode=<value optimized out>)
> >> at /opt/src/svn-current/sys/amd64/amd64/trap.c:828
> >> #7 0xffffffff80a177f1 in trap (frame=0xfffffe0093e9c630)
> >> at /opt/src/svn-current/sys/amd64/amd64/trap.c:407
> >> #8 0xffffffff809f1aac in calltrap ()
> >> at /opt/src/svn-current/sys/amd64/amd64/exception.S:289
> >> ---Type <return> to continue, or q <return> to quit---
> >> #9 0xffffffff80a054b1 in pmap_enter (pmap=<value optimized out>,
> >> va=851443712, m=0xfffffe0005b25ce8, prot=<value optimized out>,
> >> flags=2677542912, psind=<value optimized out>) at atomic.h:221
> >> #10 0xffffffff8098c4a9 in vm_fault (map=<value optimized out>,
> >> vaddr=<value optimized out>, fault_type=232 '\ufffd',
> >> fault_flags=<value optimized out>, m_hold=0x0)
> >> at /opt/src/svn-current/sys/vm/vm_fault.c:489
> >> #11 0xffffffff8098a723 in vm_fault_trap (map=0xfffff80173eb5000,
> >> vaddr=<value optimized out>, fault_type=2 '\002',
> >> fault_flags=<value optimized out>, signo=0xfffffe0093e9ca84,
> >> ucode=0xfffffe0093e9ca80) at
> >> /opt/src/svn-current/sys/vm/vm_fault.c:568
> >> #12 0xffffffff80a18326 in trap_pfault (frame=0xfffffe0093e9cac0,
> >> signo=<value optimized out>, ucode=<value optimized out>)
> >> at /opt/src/svn-current/sys/amd64/amd64/trap.c:828
> >> #13 0xffffffff80a17988 in trap (frame=0xfffffe0093e9cac0)
> >> at /opt/src/svn-current/sys/amd64/amd64/trap.c:347
> >> #14 0xffffffff809f1aac in calltrap ()
> >> at /opt/src/svn-current/sys/amd64/amd64/exception.S:289
> >> #15 0x0000000030e2a9c3 in ?? ()
> >> Previous frame inner to this frame (corrupt stack?)
> >> Current language: auto; currently minimal
> >> (kgdb) frame 9
> >> #9 0xffffffff80a054b1 in pmap_enter (pmap=<value optimized out>,
> >> va=851443712, m=0xfffffe0005b25ce8, prot=<value optimized out>,
> >> flags=2677542912, psind=<value optimized out>) at atomic.h:221
> >> 221 ATOMIC_CMPSET(long);
> >> (kgdb) l
> >> 216 }
> >> 217
> >> 218 ATOMIC_CMPSET(char);
> >> 219 ATOMIC_CMPSET(short);
> >> 220 ATOMIC_CMPSET(int);
> >> 221 ATOMIC_CMPSET(long);
> >> 222
> >> 223 /*
> >> 224 * Atomically add the value of v to the integer pointed to by p
> and
> >> return
> >> 225 * the previous value of *p.
> >> (kgdb)
> >
> > I should use kgdb from ports instead of /usr/libexec version. Similar
> > result.
> >
> > <4>WARN_ON(!mutex_is_locked(&fbc->lock))WARN_ON(!mutex_is_locked(&fbc->
> > lock))
> > panic: vm_fault: fault on nofault entry, addr: 0xfffffe000e01c000
> > cpuid = 1
> > time = 1570417211
> > KDB: stack backtrace:
> > db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame
> > 0xfffffe0093e9c260
> > vpanic() at vpanic+0x19d/frame 0xfffffe0093e9c2b0
> > panic() at panic+0x43/frame 0xfffffe0093e9c310
> > vm_fault() at vm_fault+0x2126/frame 0xfffffe0093e9c460
> > vm_fault_trap() at vm_fault_trap+0x73/frame 0xfffffe0093e9c4b0
> > trap_pfault() at trap_pfault+0x1b6/frame 0xfffffe0093e9c510
> > trap() at trap+0x2a1/frame 0xfffffe0093e9c620
> > calltrap() at calltrap+0x8/frame 0xfffffe0093e9c620
> > --- trap 0xc, rip = 0xffffffff80a054b1, rsp = 0xfffffe0093e9c6f0, rbp =
> > 0xfffffe0093e9c7a0 ---
> > pmap_enter() at pmap_enter+0x861/frame 0xfffffe0093e9c7a0
> > vm_fault() at vm_fault+0x1c69/frame 0xfffffe0093e9c8f0
> > vm_fault_trap() at vm_fault_trap+0x73/frame 0xfffffe0093e9c940
> > trap_pfault() at trap_pfault+0x1b6/frame 0xfffffe0093e9c9a0
> > trap() at trap+0x438/frame 0xfffffe0093e9cab0
> > calltrap() at calltrap+0x8/frame 0xfffffe0093e9cab0
> > --- trap 0xc, rip = 0x30e2a9c3, rsp = 0x7fffffffea50, rbp = 0x7fffffffeaa0
> > ---
> > Uptime: 3m33s
> > Dumping 945 out of 7974
> > MB:..2%..11%..21%..31%..41%..51%..61%..72%..82%..92%
> >
> > __curthread () at /opt/src/svn-current/sys/amd64/include/pcpu_aux.h:55
> > 55 __asm("movq %%gs:%P1,%0" : "=r" (td) : "n" (offsetof(struct pcp
> u,
> > (kgdb)
> >
> > Backtrace stopped: Cannot access memory at address 0x7fffffffea50
> > (kgdb) frame 10
> > #10 0xffffffff80a054b1 in atomic_fcmpset_long (dst=<optimized out>,
> > src=<optimized out>, expect=<optimized out>)
> > at /opt/src/svn-current/sys/amd64/include/atomic.h:221
> > 221 ATOMIC_CMPSET(long);
> > (kgdb) l
> > 216 }
> > 217
> > 218 ATOMIC_CMPSET(char);
> > 219 ATOMIC_CMPSET(short);
> > 220 ATOMIC_CMPSET(int);
> > 221 ATOMIC_CMPSET(long);
> > 222
> > 223 /*
> > 224 * Atomically add the value of v to the integer pointed to by p and
> > return
> > 225 * the previous value of *p.
> > (kgdb)
> >
> >
> >
> > --
> > 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.
> >
> >
> >
>
>
> --
> Mateusz Guzik <mjguzik gmail.com>
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