svn commit: r353149 - head/sys/amd64/amd64
Mateusz Guzik
mjguzik at gmail.com
Mon Oct 7 14:25:00 UTC 2019
Can you show:
sysctl vm.phys_segs
and from the crashdump:
p pv_table
On 10/7/19, Cy Schubert <Cy.Schubert at cschubert.com> wrote:
> In message <201910070406.x9746N0U009068 at slippy.cwsent.com>, Cy Schubert
> writes:
>> In message <201910062213.x96MDZv3085523 at 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_LOCKS]);
>> > }
>> > +#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 pages.
>> > + */
>> > + 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(pvd);
>> > + 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 pcpu,
> (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 at cschubert.com>
> FreeBSD UNIX: <cy at 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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