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    Subject[patch 08/13] GRU Driver V2 - resource management
    This file contains functions realted to managing GRU resources provided
    to the user. Examples include GRU context assignment, load, unload, migration, etc..


    Signed-off-by: Jack Steiner <steiner@sgi.com>

    ---
    drivers/misc/sgi-gru/grumain.c | 798 +++++++++++++++++++++++++++++++++++++++++
    1 file changed, 798 insertions(+)

    Index: linux/drivers/misc/sgi-gru/grumain.c
    ===================================================================
    --- /dev/null 1970-01-01 00:00:00.000000000 +0000
    +++ linux/drivers/misc/sgi-gru/grumain.c 2008-06-14 18:51:47.482824274 -0500
    @@ -0,0 +1,798 @@
    +/*
    + * SN Platform GRU Driver
    + *
    + * DRIVER TABLE MANAGER + GRU CONTEXT LOAD/UNLOAD
    + *
    + * This file is subject to the terms and conditions of the GNU General Public
    + * License. See the file "COPYING" in the main directory of this archive
    + * for more details.
    + *
    + * Copyright (c) 2008 Silicon Graphics, Inc. All Rights Reserved.
    + */
    +
    +#include <linux/kernel.h>
    +#include <linux/slab.h>
    +#include <linux/mm.h>
    +#include <linux/spinlock.h>
    +#include <linux/sched.h>
    +#include <linux/device.h>
    +#include <linux/list.h>
    +#include <asm/uv/uv_hub.h>
    +#include "gru.h"
    +#include "grutables.h"
    +#include "gruhandles.h"
    +
    +unsigned long options __read_mostly;
    +
    +static struct device_driver gru_driver = {
    + .name = "gru"
    +};
    +
    +static struct device gru_device = {
    + .bus_id = {0},
    + .driver = &gru_driver,
    +};
    +
    +struct device *grudev = &gru_device;
    +
    +/*
    + * Select a gru fault map to be used by the current cpu. Note that
    + * multiple cpus may be using the same map.
    + * ZZZ should "shift" be used?? Depends on HT cpu numbering
    + * ZZZ should be inline but did not work on emulator
    + */
    +int gru_cpu_fault_map_id(void)
    +{
    + return uv_blade_processor_id() % GRU_NUM_TFM;
    +}
    +
    +/*--------- ASID Management -------------------------------------------
    + *
    + * Initially, assign asids sequentially from MIN_ASID .. MAX_ASID.
    + * Once MAX is reached, flush the TLB & start over. However,
    + * some asids may still be in use. There won't be many (percentage wise) still
    + * in use. Search active contexts & determine the value of the first
    + * asid in use ("x"s below). Set "limit" to this value.
    + * This defines a block of assignable asids.
    + *
    + * When "limit" is reached, search forward from limit+1 and determine the
    + * next block of assignable asids.
    + *
    + * Repeat until MAX_ASID is reached, then start over again.
    + *
    + * Each time MAX_ASID is reached, increment the asid generation. Since
    + * the search for in-use asids only checks contexts with GRUs currently
    + * assigned, asids in some contexts will be missed. Prior to loading
    + * a context, the asid generation of the GTS asid is rechecked. If it
    + * doesn't match the current generation, a new asid will be assigned.
    + *
    + * 0---------------x------------x---------------------x----|
    + * ^-next ^-limit ^-MAX_ASID
    + *
    + * All asid manipulation & context loading/unloading is protected by the
    + * gs_lock.
    + */
    +
    +/* Hit the asid limit. Start over */
    +static int gru_wrap_asid(struct gru_state *gru)
    +{
    + gru_dbg(grudev, "gru %p\n", gru);
    + STAT(asid_wrap);
    + gru->gs_asid_gen++;
    + gru_flush_all_tlb(gru);
    + return MIN_ASID;
    +}
    +
    +/* Find the next chunk of unused asids */
    +static int gru_reset_asid_limit(struct gru_state *gru, int asid)
    +{
    + int i, gid, inuse_asid, limit;
    +
    + gru_dbg(grudev, "gru %p, asid 0x%x\n", gru, asid);
    + STAT(asid_next);
    + limit = MAX_ASID;
    + if (asid >= limit)
    + asid = gru_wrap_asid(gru);
    + gid = gru->gs_gid;
    +again:
    + for (i = 0; i < GRU_NUM_CCH; i++) {
    + if (!gru->gs_gts[i])
    + continue;
    + inuse_asid = gru->gs_gts[i]->ts_gms->ms_asids[gid].mt_asid;
    + gru_dbg(grudev, "gru %p, inuse_asid 0x%x, cxtnum %d, gts %p\n",
    + gru, inuse_asid, i, gru->gs_gts[i]);
    + if (inuse_asid == asid) {
    + asid += ASID_INC;
    + if (asid >= limit) {
    + /*
    + * empty range: reset the range limit and
    + * start over
    + */
    + limit = MAX_ASID;
    + if (asid >= MAX_ASID)
    + asid = gru_wrap_asid(gru);
    + goto again;
    + }
    + }
    +
    + if ((inuse_asid > asid) && (inuse_asid < limit))
    + limit = inuse_asid;
    + }
    + gru->gs_asid_limit = limit;
    + gru->gs_asid = asid;
    + gru_dbg(grudev, "gru %p, new asid 0x%x, new_limit 0x%x\n", gru, asid,
    + limit);
    + return asid;
    +}
    +
    +/* Assign a new ASID to a thread context. */
    +static int gru_assign_asid(struct gru_state *gru)
    +{
    + int asid;
    +
    + spin_lock(&gru->gs_asid_lock);
    + gru->gs_asid += ASID_INC;
    + asid = gru->gs_asid;
    + if (asid >= gru->gs_asid_limit)
    + asid = gru_reset_asid_limit(gru, asid);
    + spin_unlock(&gru->gs_asid_lock);
    +
    + gru_dbg(grudev, "gru %p, asid 0x%x\n", gru, asid);
    + return asid;
    +}
    +
    +/*
    + * Clear n bits in a word. Return a word indicating the bits that were cleared.
    + * Optionally, build an array of chars that contain the bit numbers allocated.
    + */
    +static unsigned long reserve_resources(unsigned long *p, int n, int mmax,
    + char *idx)
    +{
    + unsigned long bits = 0;
    + int i;
    +
    + do {
    + i = find_first_bit(p, mmax);
    + if (i == mmax)
    + BUG();
    + __clear_bit(i, p);
    + __set_bit(i, &bits);
    + if (idx)
    + *idx++ = i;
    + } while (--n);
    + return bits;
    +}
    +
    +unsigned long reserve_gru_cb_resources(struct gru_state *gru, int cbr_au_count,
    + char *cbmap)
    +{
    + return reserve_resources(&gru->gs_cbr_map, cbr_au_count, GRU_CBR_AU,
    + cbmap);
    +}
    +
    +unsigned long reserve_gru_ds_resources(struct gru_state *gru, int dsr_au_count,
    + char *dsmap)
    +{
    + return reserve_resources(&gru->gs_dsr_map, dsr_au_count, GRU_DSR_AU,
    + dsmap);
    +}
    +
    +static void reserve_gru_resources(struct gru_state *gru,
    + struct gru_thread_state *gts)
    +{
    + gru->gs_active_contexts++;
    + gts->ts_cbr_map =
    + reserve_gru_cb_resources(gru, gts->ts_cbr_au_count,
    + gts->ts_cbr_idx);
    + gts->ts_dsr_map =
    + reserve_gru_ds_resources(gru, gts->ts_dsr_au_count, NULL);
    +}
    +
    +static void free_gru_resources(struct gru_state *gru,
    + struct gru_thread_state *gts)
    +{
    + gru->gs_active_contexts--;
    + gru->gs_cbr_map |= gts->ts_cbr_map;
    + gru->gs_dsr_map |= gts->ts_dsr_map;
    +}
    +
    +/*
    + * Check if a GRU has sufficient free resources to satisfy an allocation
    + * request. Note: GRU locks may or may not be held when this is called. If
    + * not held, recheck after acquiring the appropriate locks.
    + *
    + * Returns 1 if sufficient resources, 0 if not
    + */
    +static int check_gru_resources(struct gru_state *gru, int cbr_au_count,
    + int dsr_au_count, int max_active_contexts)
    +{
    + return hweight64(gru->gs_cbr_map) >= cbr_au_count
    + && hweight64(gru->gs_dsr_map) >= dsr_au_count
    + && gru->gs_active_contexts < max_active_contexts;
    +}
    +
    +/*
    + * TLB manangment requires tracking all GRU chiplets that have loaded a GSEG
    + * context.
    + */
    +static int gru_load_mm_tracker(struct gru_state *gru, struct gru_mm_struct *gms,
    + int ctxnum)
    +{
    + struct gru_mm_tracker *asids = &gms->ms_asids[gru->gs_gid];
    + unsigned short ctxbitmap = (1 << ctxnum);
    + int asid;
    +
    + spin_lock(&gms->ms_asid_lock);
    + asid = asids->mt_asid;
    +
    + if (asid == 0 || asids->mt_asid_gen != gru->gs_asid_gen) {
    + asid = gru_assign_asid(gru);
    + asids->mt_asid = asid;
    + asids->mt_asid_gen = gru->gs_asid_gen;
    + STAT(asid_new);
    + } else {
    + STAT(asid_reuse);
    + }
    +
    + BUG_ON(asids->mt_ctxbitmap & ctxbitmap);
    + asids->mt_ctxbitmap |= ctxbitmap;
    + if (!test_bit(gru->gs_gid, gms->ms_asidmap))
    + __set_bit(gru->gs_gid, gms->ms_asidmap);
    + spin_unlock(&gms->ms_asid_lock);
    +
    + gru_dbg(grudev,
    + "gru %x, gms %p, ctxnum 0x%d, asid 0x%x, asidmap 0x%lx\n",
    + gru->gs_gid, gms, ctxnum, asid, gms->ms_asidmap[0]);
    + return asid;
    +}
    +
    +static void gru_unload_mm_tracker(struct gru_state *gru,
    + struct gru_mm_struct *gms, int ctxnum)
    +{
    + struct gru_mm_tracker *asids;
    + unsigned short ctxbitmap;
    +
    + asids = &gms->ms_asids[gru->gs_gid];
    + ctxbitmap = (1 << ctxnum);
    + spin_lock(&gms->ms_asid_lock);
    + BUG_ON((asids->mt_ctxbitmap & ctxbitmap) != ctxbitmap);
    + asids->mt_ctxbitmap ^= ctxbitmap;
    + gru_dbg(grudev, "gru %x, gms %p, ctxnum 0x%d, asidmap 0x%lx\n",
    + gru->gs_gid, gms, ctxnum, gms->ms_asidmap[0]);
    + spin_unlock(&gms->ms_asid_lock);
    +}
    +
    +/*
    + * Decrement the reference count on a GTS structure. Free the structure
    + * if the reference count goes to zero.
    + */
    +void gts_drop(struct gru_thread_state *gts)
    +{
    + if (gts && atomic_dec_return(&gts->ts_refcnt) == 0) {
    + gru_drop_mmu_notifier(gts->ts_gms);
    + kfree(gts);
    + STAT(gts_free);
    + }
    +}
    +
    +/*
    + * Locate the GTS structure for the current thread.
    + */
    +static struct gru_thread_state *gru_find_current_gts_nolock(struct gru_vma_data
    + *vdata, int tsid)
    +{
    + struct gru_thread_state *gts;
    +
    + list_for_each_entry(gts, &vdata->vd_head, ts_next)
    + if (gts->ts_tsid == tsid)
    + return gts;
    + return NULL;
    +}
    +
    +/*
    + * Allocate a thread state structure.
    + */
    +static struct gru_thread_state *gru_alloc_gts(struct vm_area_struct *vma,
    + struct gru_vma_data *vdata,
    + int tsid)
    +{
    + struct gru_thread_state *gts;
    + int bytes;
    +
    + bytes = DSR_BYTES(vdata->vd_dsr_au_count) +
    + CBR_BYTES(vdata->vd_cbr_au_count);
    + bytes += sizeof(struct gru_thread_state);
    + gts = kzalloc(bytes, GFP_KERNEL);
    + if (!gts)
    + return NULL;
    +
    + STAT(gts_alloc);
    + atomic_set(&gts->ts_refcnt, 1);
    + mutex_init(&gts->ts_ctxlock);
    + gts->ts_cbr_au_count = vdata->vd_cbr_au_count;
    + gts->ts_dsr_au_count = vdata->vd_dsr_au_count;
    + gts->ts_user_options = vdata->vd_user_options;
    + gts->ts_tsid = tsid;
    + gts->ts_user_options = vdata->vd_user_options;
    + gts->ts_ctxnum = NULLCTX;
    + gts->ts_mm = current->mm;
    + gts->ts_vma = vma;
    + gts->ts_tlb_int_select = -1;
    + gts->ts_gms = gru_register_mmu_notifier();
    + if (!gts->ts_gms)
    + goto err;
    +
    + gru_dbg(grudev, "alloc vdata %p, new gts %p\n", vdata, gts);
    + return gts;
    +
    +err:
    + gts_drop(gts);
    + return NULL;
    +}
    +
    +/*
    + * Allocate a vma private data structure.
    + */
    +struct gru_vma_data *gru_alloc_vma_data(struct vm_area_struct *vma, int tsid)
    +{
    + struct gru_vma_data *vdata = NULL;
    +
    + vdata = kmalloc(sizeof(*vdata), GFP_KERNEL);
    + if (!vdata)
    + return NULL;
    +
    + INIT_LIST_HEAD(&vdata->vd_head);
    + spin_lock_init(&vdata->vd_lock);
    + gru_dbg(grudev, "alloc vdata %p\n", vdata);
    + return vdata;
    +}
    +
    +/*
    + * Find the thread state structure for the current thread.
    + */
    +struct gru_thread_state *gru_find_thread_state(struct vm_area_struct *vma,
    + int tsid)
    +{
    + struct gru_vma_data *vdata = vma->vm_private_data;
    + struct gru_thread_state *gts;
    +
    + spin_lock(&vdata->vd_lock);
    + gts = gru_find_current_gts_nolock(vdata, tsid);
    + spin_unlock(&vdata->vd_lock);
    + gru_dbg(grudev, "vma %p, gts %p\n", vma, gts);
    + return gts;
    +}
    +
    +/*
    + * Allocate a new thread state for a GSEG. Note that races may allow
    + * another thread to race to create a gts.
    + */
    +struct gru_thread_state *gru_alloc_thread_state(struct vm_area_struct *vma,
    + int tsid)
    +{
    + struct gru_vma_data *vdata = vma->vm_private_data;
    + struct gru_thread_state *gts, *ngts;
    +
    + gts = gru_alloc_gts(vma, vdata, tsid);
    + if (!gts)
    + return NULL;
    +
    + spin_lock(&vdata->vd_lock);
    + ngts = gru_find_current_gts_nolock(vdata, tsid);
    + if (ngts) {
    + gts_drop(gts);
    + gts = ngts;
    + STAT(gts_double_allocate);
    + } else {
    + list_add(&gts->ts_next, &vdata->vd_head);
    + }
    + spin_unlock(&vdata->vd_lock);
    + gru_dbg(grudev, "vma %p, gts %p\n", vma, gts);
    + return gts;
    +}
    +
    +/*
    + * Free the GRU context assigned to the thread state.
    + */
    +static void gru_free_gru_context(struct gru_thread_state *gts)
    +{
    + struct gru_state *gru;
    +
    + gru = gts->ts_gru;
    + gru_dbg(grudev, "gts %p, gru %p\n", gts, gru);
    +
    + spin_lock(&gru->gs_lock);
    + gru->gs_gts[gts->ts_ctxnum] = NULL;
    + free_gru_resources(gru, gts);
    + BUG_ON(test_bit(gts->ts_ctxnum, &gru->gs_context_map) == 0);
    + __clear_bit(gts->ts_ctxnum, &gru->gs_context_map);
    + gts->ts_ctxnum = NULLCTX;
    + gts->ts_gru = NULL;
    + spin_unlock(&gru->gs_lock);
    +
    + gts_drop(gts);
    + STAT(free_context);
    +}
    +
    +/*
    + * Prefetching cachelines help hardware performance.
    + */
    +static void prefetch_data(void *p, int num, int stride)
    +{
    + while (num-- > 0) {
    + prefetchw(p);
    + p += stride;
    + }
    +}
    +
    +static inline long gru_copy_handle(void *d, void *s)
    +{
    + memcpy(d, s, GRU_HANDLE_BYTES);
    + return GRU_HANDLE_BYTES;
    +}
    +
    +/* rewrite in assembly & use lots of prefetch */
    +static void gru_load_context_data(void *save, void *grubase, int ctxnum,
    + unsigned long cbrmap, unsigned long dsrmap)
    +{
    + void *gseg, *cb, *cbe;
    + unsigned long length;
    + int i, scr;
    +
    + gseg = grubase + ctxnum * GRU_GSEG_STRIDE;
    + length = hweight64(dsrmap) * GRU_DSR_AU_BYTES;
    + prefetch_data(gseg + GRU_DS_BASE, length / GRU_CACHE_LINE_BYTES,
    + GRU_CACHE_LINE_BYTES);
    +
    + cb = gseg + GRU_CB_BASE;
    + cbe = grubase + GRU_CBE_BASE;
    + for_each_cbr_in_allocation_map(i, &cbrmap, scr) {
    + prefetch_data(cb, 1, GRU_CACHE_LINE_BYTES);
    + prefetch_data(cbe + i * GRU_HANDLE_STRIDE, 1,
    + GRU_CACHE_LINE_BYTES);
    + cb += GRU_HANDLE_STRIDE;
    + }
    +
    + cb = gseg + GRU_CB_BASE;
    + for_each_cbr_in_allocation_map(i, &cbrmap, scr) {
    + save += gru_copy_handle(cb, save);
    + save += gru_copy_handle(cbe + i * GRU_HANDLE_STRIDE, save);
    + cb += GRU_HANDLE_STRIDE;
    + }
    +
    + memcpy(gseg + GRU_DS_BASE, save, length);
    +}
    +
    +static void gru_unload_context_data(void *save, void *grubase, int ctxnum,
    + unsigned long cbrmap, unsigned long dsrmap)
    +{
    + void *gseg, *cb, *cbe;
    + unsigned long length;
    + int i, scr;
    +
    + gseg = grubase + ctxnum * GRU_GSEG_STRIDE;
    +
    + cb = gseg + GRU_CB_BASE;
    + cbe = grubase + GRU_CBE_BASE;
    + for_each_cbr_in_allocation_map(i, &cbrmap, scr) {
    + save += gru_copy_handle(save, cb);
    + save += gru_copy_handle(save, cbe + i * GRU_HANDLE_STRIDE);
    + cb += GRU_HANDLE_STRIDE;
    + }
    + length = hweight64(dsrmap) * GRU_DSR_AU_BYTES;
    + memcpy(save, gseg + GRU_DS_BASE, length);
    +}
    +
    +void gru_unload_context(struct gru_thread_state *gts, int savestate)
    +{
    + struct gru_state *gru = gts->ts_gru;
    + struct gru_context_configuration_handle *cch;
    + int ctxnum = gts->ts_ctxnum;
    +
    + zap_page_range(gts->ts_vma, UGRUADDR(gts), GRU_GSEG_PAGESIZE, NULL);
    + cch = get_cch(gru->gs_gru_base_vaddr, ctxnum);
    +
    + lock_cch_handle(cch);
    + if (cch_interrupt_sync(cch))
    + BUG();
    + gru_dbg(grudev, "gts %p\n", gts);
    +
    + gru_unload_mm_tracker(gru, gts->ts_gms, gts->ts_ctxnum);
    + if (savestate)
    + gru_unload_context_data(gts->ts_gdata, gru->gs_gru_base_vaddr,
    + ctxnum, gts->ts_cbr_map,
    + gts->ts_dsr_map);
    +
    + if (cch_deallocate(cch))
    + BUG();
    + gts->ts_force_unload = 0; /* ts_force_unload locked by CCH lock */
    + unlock_cch_handle(cch);
    +
    + gru_free_gru_context(gts);
    + STAT(unload_context);
    +}
    +
    +/*
    + * Load a GRU context by copying it from the thread data structure in memory
    + * to the GRU.
    + */
    +static void gru_load_context(struct gru_thread_state *gts)
    +{
    + struct gru_state *gru = gts->ts_gru;
    + struct gru_context_configuration_handle *cch;
    + int err, asid, ctxnum = gts->ts_ctxnum;
    +
    + gru_dbg(grudev, "gts %p\n", gts);
    + cch = get_cch(gru->gs_gru_base_vaddr, ctxnum);
    +
    + lock_cch_handle(cch);
    + asid = gru_load_mm_tracker(gru, gts->ts_gms, gts->ts_ctxnum);
    + cch->tfm_fault_bit_enable =
    + (gts->ts_user_options == GRU_OPT_MISS_FMM_POLL
    + || gts->ts_user_options == GRU_OPT_MISS_FMM_INTR);
    + cch->tlb_int_enable = (gts->ts_user_options == GRU_OPT_MISS_FMM_INTR);
    + if (cch->tlb_int_enable) {
    + gts->ts_tlb_int_select = gru_cpu_fault_map_id();
    + cch->tlb_int_select = gts->ts_tlb_int_select;
    + }
    + cch->tfm_done_bit_enable = 0;
    + err = cch_allocate(cch, asid, gts->ts_cbr_map, gts->ts_dsr_map);
    + if (err) {
    + gru_dbg(grudev,
    + "err %d: cch %p, gts %p, cbr 0x%lx, dsr 0x%lx\n",
    + err, cch, gts, gts->ts_cbr_map, gts->ts_dsr_map);
    + BUG();
    + }
    +
    + gru_load_context_data(gts->ts_gdata, gru->gs_gru_base_vaddr, ctxnum,
    + gts->ts_cbr_map, gts->ts_dsr_map);
    +
    + if (cch_start(cch))
    + BUG();
    + unlock_cch_handle(cch);
    +
    + STAT(load_context);
    +}
    +
    +/*
    + * Update fields in an active CCH:
    + * - retarget interrupts on local blade
    + * - force a delayed context unload by clearing the CCH asids. This
    + * forces TLB misses for new GRU instructions. The context is unloaded
    + * when the next TLB miss occurs.
    + */
    +static int gru_update_cch(struct gru_thread_state *gts, int int_select)
    +{
    + struct gru_context_configuration_handle *cch;
    + struct gru_state *gru = gts->ts_gru;
    + int i, ctxnum = gts->ts_ctxnum, ret = 0;
    +
    + cch = get_cch(gru->gs_gru_base_vaddr, ctxnum);
    +
    + lock_cch_handle(cch);
    + if (cch->state == CCHSTATE_ACTIVE) {
    + if (gru->gs_gts[gts->ts_ctxnum] != gts)
    + goto exit;
    + if (cch_interrupt(cch))
    + BUG();
    + if (int_select >= 0) {
    + gts->ts_tlb_int_select = int_select;
    + cch->tlb_int_select = int_select;
    + } else {
    + for (i = 0; i < 8; i++)
    + cch->asid[i] = 0;
    + cch->tfm_fault_bit_enable = 0;
    + cch->tlb_int_enable = 0;
    + gts->ts_force_unload = 1;
    + }
    + if (cch_start(cch))
    + BUG();
    + ret = 1;
    + }
    +exit:
    + unlock_cch_handle(cch);
    + return ret;
    +}
    +
    +/*
    + * Update CCH tlb interrupt select. Required when all the following is true:
    + * - task's GRU context is loaded into a GRU
    + * - task is using interrupt notification for TLB faults
    + * - task has migrated to a different cpu on the same blade where
    + * it was previously running.
    + */
    +static int gru_retarget_intr(struct gru_thread_state *gts)
    +{
    + if (gts->ts_tlb_int_select < 0
    + || gts->ts_tlb_int_select == gru_cpu_fault_map_id())
    + return 0;
    +
    + gru_dbg(grudev, "retarget from %d to %d\n", gts->ts_tlb_int_select,
    + gru_cpu_fault_map_id());
    + return gru_update_cch(gts, gru_cpu_fault_map_id());
    +}
    +
    +
    +/*
    + * Insufficient GRU resources available on the local blade. Steal a context from
    + * a process. This is a hack until a _real_ resource scheduler is written....
    + */
    +#define next_ctxnum(n) ((n) < GRU_NUM_CCH - 2 ? (n) + 1 : 0)
    +#define next_gru(b, g) (((g) < &(b)->bs_grus[GRU_CHIPLETS_PER_BLADE - 1]) ? \
    + ((g)+1) : &(b)->bs_grus[0])
    +
    +static void gru_steal_context(struct gru_thread_state *gts)
    +{
    + struct gru_blade_state *blade;
    + struct gru_state *gru, *gru0;
    + struct gru_thread_state *ngts = NULL;
    + int ctxnum, ctxnum0, flag = 0, cbr, dsr;
    +
    + cbr = gts->ts_cbr_au_count;
    + dsr = gts->ts_dsr_au_count;
    +
    + preempt_disable();
    + blade = gru_base[uv_numa_blade_id()];
    + spin_lock(&blade->bs_lock);
    +
    + ctxnum = next_ctxnum(blade->bs_lru_ctxnum);
    + gru = blade->bs_lru_gru;
    + if (ctxnum == 0)
    + gru = next_gru(blade, gru);
    + ctxnum0 = ctxnum;
    + gru0 = gru;
    + while (1) {
    + if (check_gru_resources(gru, cbr, dsr, GRU_NUM_CCH))
    + break;
    + spin_lock(&gru->gs_lock);
    + for (; ctxnum < GRU_NUM_CCH; ctxnum++) {
    + if (flag && gru == gru0 && ctxnum == ctxnum0)
    + break;
    + ngts = gru->gs_gts[ctxnum];
    + /*
    + * We are grabbing locks out of order, so trylock is
    + * needed. GTSs are usually not locked, so the odds of
    + * success are high. If trylock fails, try to steal a
    + * different GSEG.
    + */
    + if (ngts && mutex_trylock(&ngts->ts_ctxlock))
    + break;
    + ngts = NULL;
    + flag = 1;
    + }
    + spin_unlock(&gru->gs_lock);
    + if (ngts || (flag && gru == gru0 && ctxnum == ctxnum0))
    + break;
    + ctxnum = 0;
    + gru = next_gru(blade, gru);
    + }
    + blade->bs_lru_gru = gru;
    + blade->bs_lru_ctxnum = ctxnum;
    + spin_unlock(&blade->bs_lock);
    + preempt_enable();
    +
    + if (ngts) {
    + STAT(steal_context);
    + ngts->ts_steal_jiffies = jiffies;
    + gru_unload_context(ngts, 1);
    + mutex_unlock(&ngts->ts_ctxlock);
    + } else {
    + STAT(steal_context_failed);
    + }
    + gru_dbg(grudev,
    + "stole gru %x, ctxnum %d from gts %p. Need cb %d, ds %d;"
    + " avail cb %ld, ds %ld\n",
    + gru->gs_gid, ctxnum, ngts, cbr, dsr, hweight64(gru->gs_cbr_map),
    + hweight64(gru->gs_dsr_map));
    +}
    +
    +/*
    + * Scan the GRUs on the local blade & assign a GRU context.
    + */
    +static struct gru_state *gru_assign_gru_context(struct gru_thread_state *gts)
    +{
    + struct gru_state *gru, *grux;
    + int i, max_active_contexts;
    +
    + preempt_disable();
    +
    +again:
    + gru = NULL;
    + max_active_contexts = GRU_NUM_CCH;
    + for_each_gru_on_blade(grux, uv_numa_blade_id(), i) {
    + if (check_gru_resources(grux, gts->ts_cbr_au_count,
    + gts->ts_dsr_au_count,
    + max_active_contexts)) {
    + gru = grux;
    + max_active_contexts = grux->gs_active_contexts;
    + if (max_active_contexts == 0)
    + break;
    + }
    + }
    +
    + if (gru) {
    + spin_lock(&gru->gs_lock);
    + if (!check_gru_resources(gru, gts->ts_cbr_au_count,
    + gts->ts_dsr_au_count, GRU_NUM_CCH)) {
    + spin_unlock(&gru->gs_lock);
    + goto again;
    + }
    + reserve_gru_resources(gru, gts);
    + gts->ts_gru = gru;
    + gts->ts_ctxnum =
    + find_first_zero_bit(&gru->gs_context_map, GRU_NUM_CCH);
    + BUG_ON(gts->ts_ctxnum == GRU_NUM_CCH);
    + atomic_inc(&gts->ts_refcnt);
    + gru->gs_gts[gts->ts_ctxnum] = gts;
    + __set_bit(gts->ts_ctxnum, &gru->gs_context_map);
    + spin_unlock(&gru->gs_lock);
    +
    + STAT(assign_context);
    + gru_dbg(grudev,
    + "gseg %p, gts %p, gru %x, ctx %d, cbr %d, dsr %d\n",
    + gseg_virtual_address(gts->ts_gru, gts->ts_ctxnum), gts,
    + gts->ts_gru->gs_gid, gts->ts_ctxnum,
    + gts->ts_cbr_au_count, gts->ts_dsr_au_count);
    + } else {
    + gru_dbg(grudev, "failed to allocate a GTS %s\n", "");
    + STAT(assign_context_failed);
    + }
    +
    + preempt_enable();
    + return gru;
    +}
    +
    +/*
    + * gru_nopage
    + *
    + * Map the user's GRU segment
    + */
    +int gru_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
    +{
    + struct gru_thread_state *gts;
    + unsigned long paddr, vaddr;
    +
    + vaddr = (unsigned long)vmf->virtual_address;
    + gru_dbg(grudev, "vma %p, vaddr 0x%lx (0x%lx)\n",
    + vma, vaddr, GSEG_BASE(vaddr));
    + STAT(nopfn);
    +
    + gts = gru_find_thread_state(vma, TSID(vaddr, vma));
    + if (!gts)
    + return VM_FAULT_SIGBUS;
    +
    +again:
    + preempt_disable();
    + mutex_lock(&gts->ts_ctxlock);
    + if (gts->ts_gru) {
    + if (gts->ts_gru->gs_blade_id != uv_numa_blade_id()) {
    + STAT(migrated_nopfn_unload);
    + gru_unload_context(gts, 1);
    + } else {
    + if (gru_retarget_intr(gts))
    + STAT(migrated_nopfn_retarget);
    + }
    + }
    +
    + if (!gts->ts_gru) {
    + while (!gru_assign_gru_context(gts)) {
    + mutex_unlock(&gts->ts_ctxlock);
    + preempt_enable();
    + schedule_timeout(GRU_ASSIGN_DELAY); /* true hack ZZZ */
    + if (gts->ts_steal_jiffies + GRU_STEAL_DELAY < jiffies)
    + gru_steal_context(gts);
    + goto again;
    + }
    + gru_load_context(gts);
    + paddr = gseg_physical_address(gts->ts_gru, gts->ts_ctxnum);
    + remap_pfn_range(vma, vaddr & ~(GRU_GSEG_PAGESIZE - 1),
    + paddr >> PAGE_SHIFT, GRU_GSEG_PAGESIZE,
    + vma->vm_page_prot);
    + }
    +
    + mutex_unlock(&gts->ts_ctxlock);
    + preempt_enable();
    +
    + return VM_FAULT_NOPAGE;
    +}
    +
    --


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      Last update: 2008-06-15 16:09    [W:0.074 / U:90.460 seconds]
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