ttm_memory.c

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/**************************************************************************
 *
 * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sub license, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 * USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 **************************************************************************/

#define pr_fmt(fmt) "[TTM] " fmt

#include <drm/ttm/ttm_memory.h>
#include <drm/ttm/ttm_module.h>
#include <drm/ttm/ttm_page_alloc.h>
#include <linux/spinlock.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/slab.h>

#define TTM_MEMORY_ALLOC_RETRIES 4

struct ttm_mem_zone {
    struct kobject kobj;
    struct ttm_mem_global *glob;
    const char *name;
    uint64_t zone_mem;
    uint64_t emer_mem;
    uint64_t max_mem;
    uint64_t swap_limit;
    uint64_t used_mem;
};

static struct attribute ttm_mem_sys = {
    .name = "zone_memory",
    .mode = S_IRUGO
};
static struct attribute ttm_mem_emer = {
    .name = "emergency_memory",
    .mode = S_IRUGO | S_IWUSR
};
static struct attribute ttm_mem_max = {
    .name = "available_memory",
    .mode = S_IRUGO | S_IWUSR
};
static struct attribute ttm_mem_swap = {
    .name = "swap_limit",
    .mode = S_IRUGO | S_IWUSR
};
static struct attribute ttm_mem_used = {
    .name = "used_memory",
    .mode = S_IRUGO
};

static void ttm_mem_zone_kobj_release(struct kobject *kobj)
{
    struct ttm_mem_zone *zone =
        container_of(kobj, struct ttm_mem_zone, kobj);

    pr_info("Zone %7s: Used memory at exit: %llu kiB\n",
        zone->name, (unsigned long long)zone->used_mem >> 10);
    kfree(zone);
}

static ssize_t ttm_mem_zone_show(struct kobject *kobj,
                 struct attribute *attr,
                 char *buffer)
{
    struct ttm_mem_zone *zone =
        container_of(kobj, struct ttm_mem_zone, kobj);
    uint64_t val = 0;

    spin_lock(&zone->glob->lock);
    if (attr == &ttm_mem_sys)
        val = zone->zone_mem;
    else if (attr == &ttm_mem_emer)
        val = zone->emer_mem;
    else if (attr == &ttm_mem_max)
        val = zone->max_mem;
    else if (attr == &ttm_mem_swap)
        val = zone->swap_limit;
    else if (attr == &ttm_mem_used)
        val = zone->used_mem;
    spin_unlock(&zone->glob->lock);

    return snprintf(buffer, PAGE_SIZE, "%llu\n",
            (unsigned long long) val >> 10);
}

static void ttm_check_swapping(struct ttm_mem_global *glob);

static ssize_t ttm_mem_zone_store(struct kobject *kobj,
                  struct attribute *attr,
                  const char *buffer,
                  size_t size)
{
    struct ttm_mem_zone *zone =
        container_of(kobj, struct ttm_mem_zone, kobj);
    int chars;
    unsigned long val;
    uint64_t val64;

    chars = sscanf(buffer, "%lu", &val);
    if (chars == 0)
        return size;

    val64 = val;
    val64 <<= 10;

    spin_lock(&zone->glob->lock);
    if (val64 > zone->zone_mem)
        val64 = zone->zone_mem;
    if (attr == &ttm_mem_emer) {
        zone->emer_mem = val64;
        if (zone->max_mem > val64)
            zone->max_mem = val64;
    } else if (attr == &ttm_mem_max) {
        zone->max_mem = val64;
        if (zone->emer_mem < val64)
            zone->emer_mem = val64;
    } else if (attr == &ttm_mem_swap)
        zone->swap_limit = val64;
    spin_unlock(&zone->glob->lock);

    ttm_check_swapping(zone->glob);

    return size;
}

static struct attribute *ttm_mem_zone_attrs[] = {
    &ttm_mem_sys,
    &ttm_mem_emer,
    &ttm_mem_max,
    &ttm_mem_swap,
    &ttm_mem_used,
    NULL
};

static const struct sysfs_ops ttm_mem_zone_ops = {
    .show = &ttm_mem_zone_show,
    .store = &ttm_mem_zone_store
};

static struct kobj_type ttm_mem_zone_kobj_type = {
    .release = &ttm_mem_zone_kobj_release,
    .sysfs_ops = &ttm_mem_zone_ops,
    .default_attrs = ttm_mem_zone_attrs,
};

static void ttm_mem_global_kobj_release(struct kobject *kobj)
{
    struct ttm_mem_global *glob =
        container_of(kobj, struct ttm_mem_global, kobj);

    kfree(glob);
}

static struct kobj_type ttm_mem_glob_kobj_type = {
    .release = &ttm_mem_global_kobj_release,
};

static bool ttm_zones_above_swap_target(struct ttm_mem_global *glob,
                    bool from_wq, uint64_t extra)
{
    unsigned int i;
    struct ttm_mem_zone *zone;
    uint64_t target;

    for (i = 0; i < glob->num_zones; ++i) {
        zone = glob->zones[i];

        if (from_wq)
            target = zone->swap_limit;
        else if (capable(CAP_SYS_ADMIN))
            target = zone->emer_mem;
        else
            target = zone->max_mem;

        target = (extra > target) ? 0ULL : target;

        if (zone->used_mem > target)
            return true;
    }
    return false;
}

static void ttm_shrink(struct ttm_mem_global *glob, bool from_wq,
               uint64_t extra)
{
    int ret;
    struct ttm_mem_shrink *shrink;

    spin_lock(&glob->lock);
    if (glob->shrink == NULL)
        goto out;

    while (ttm_zones_above_swap_target(glob, from_wq, extra)) {
        shrink = glob->shrink;
        spin_unlock(&glob->lock);
        ret = shrink->do_shrink(shrink);
        spin_lock(&glob->lock);
        if (unlikely(ret != 0))
            goto out;
    }
out:
    spin_unlock(&glob->lock);
}



static void ttm_shrink_work(struct work_struct *work)
{
    struct ttm_mem_global *glob =
        container_of(work, struct ttm_mem_global, work);

    ttm_shrink(glob, true, 0ULL);
}

static int ttm_mem_init_kernel_zone(struct ttm_mem_global *glob,
                    const struct sysinfo *si)
{
    struct ttm_mem_zone *zone = kzalloc(sizeof(*zone), GFP_KERNEL);
    uint64_t mem;
    int ret;

    if (unlikely(!zone))
        return -ENOMEM;

    mem = si->totalram - si->totalhigh;
    mem *= si->mem_unit;

    zone->name = "kernel";
    zone->zone_mem = mem;
    zone->max_mem = mem >> 1;
    zone->emer_mem = (mem >> 1) + (mem >> 2);
    zone->swap_limit = zone->max_mem - (mem >> 3);
    zone->used_mem = 0;
    zone->glob = glob;
    glob->zone_kernel = zone;
    ret = kobject_init_and_add(
        &zone->kobj, &ttm_mem_zone_kobj_type, &glob->kobj, zone->name);
    if (unlikely(ret != 0)) {
        kobject_put(&zone->kobj);
        return ret;
    }
    glob->zones[glob->num_zones++] = zone;
    return 0;
}

#ifdef CONFIG_HIGHMEM
static int ttm_mem_init_highmem_zone(struct ttm_mem_global *glob,
                     const struct sysinfo *si)
{
    struct ttm_mem_zone *zone;
    uint64_t mem;
    int ret;

    if (si->totalhigh == 0)
        return 0;

    zone = kzalloc(sizeof(*zone), GFP_KERNEL);
    if (unlikely(!zone))
        return -ENOMEM;

    mem = si->totalram;
    mem *= si->mem_unit;

    zone->name = "highmem";
    zone->zone_mem = mem;
    zone->max_mem = mem >> 1;
    zone->emer_mem = (mem >> 1) + (mem >> 2);
    zone->swap_limit = zone->max_mem - (mem >> 3);
    zone->used_mem = 0;
    zone->glob = glob;
    glob->zone_highmem = zone;
    ret = kobject_init_and_add(
        &zone->kobj, &ttm_mem_zone_kobj_type, &glob->kobj, zone->name);
    if (unlikely(ret != 0)) {
        kobject_put(&zone->kobj);
        return ret;
    }
    glob->zones[glob->num_zones++] = zone;
    return 0;
}
#else
static int ttm_mem_init_dma32_zone(struct ttm_mem_global *glob,
                   const struct sysinfo *si)
{
    struct ttm_mem_zone *zone = kzalloc(sizeof(*zone), GFP_KERNEL);
    uint64_t mem;
    int ret;

    if (unlikely(!zone))
        return -ENOMEM;

    mem = si->totalram;
    mem *= si->mem_unit;

    if (mem <= ((uint64_t) 1ULL << 32)) {
        kfree(zone);
        return 0;
    }

    /*
     * Limit max dma32 memory to 4GB for now
     * until we can figure out how big this
     * zone really is.
     */

    mem = ((uint64_t) 1ULL << 32);
    zone->name = "dma32";
    zone->zone_mem = mem;
    zone->max_mem = mem >> 1;
    zone->emer_mem = (mem >> 1) + (mem >> 2);
    zone->swap_limit = zone->max_mem - (mem >> 3);
    zone->used_mem = 0;
    zone->glob = glob;
    glob->zone_dma32 = zone;
    ret = kobject_init_and_add(
        &zone->kobj, &ttm_mem_zone_kobj_type, &glob->kobj, zone->name);
    if (unlikely(ret != 0)) {
        kobject_put(&zone->kobj);
        return ret;
    }
    glob->zones[glob->num_zones++] = zone;
    return 0;
}
#endif

int ttm_mem_global_init(struct ttm_mem_global *glob)
{
    struct sysinfo si;
    int ret;
    int i;
    struct ttm_mem_zone *zone;

    spin_lock_init(&glob->lock);
    glob->swap_queue = create_singlethread_workqueue("ttm_swap");
    INIT_WORK(&glob->work, ttm_shrink_work);
    init_waitqueue_head(&glob->queue);
    ret = kobject_init_and_add(
        &glob->kobj, &ttm_mem_glob_kobj_type, ttm_get_kobj(), "memory_accounting");
    if (unlikely(ret != 0)) {
        kobject_put(&glob->kobj);
        return ret;
    }

    si_meminfo(&si);

    ret = ttm_mem_init_kernel_zone(glob, &si);
    if (unlikely(ret != 0))
        goto out_no_zone;
#ifdef CONFIG_HIGHMEM
    ret = ttm_mem_init_highmem_zone(glob, &si);
    if (unlikely(ret != 0))
        goto out_no_zone;
#else
    ret = ttm_mem_init_dma32_zone(glob, &si);
    if (unlikely(ret != 0))
        goto out_no_zone;
#endif
    for (i = 0; i < glob->num_zones; ++i) {
        zone = glob->zones[i];
        pr_info("Zone %7s: Available graphics memory: %llu kiB\n",
            zone->name, (unsigned long long)zone->max_mem >> 10);
    }
    ttm_page_alloc_init(glob, glob->zone_kernel->max_mem/(2*PAGE_SIZE));
    ttm_dma_page_alloc_init(glob, glob->zone_kernel->max_mem/(2*PAGE_SIZE));
    return 0;
out_no_zone:
    ttm_mem_global_release(glob);
    return ret;
}
EXPORT_SYMBOL(ttm_mem_global_init);

void ttm_mem_global_release(struct ttm_mem_global *glob)
{
    unsigned int i;
    struct ttm_mem_zone *zone;

    /* let the page allocator first stop the shrink work. */
    ttm_page_alloc_fini();
    ttm_dma_page_alloc_fini();

    flush_workqueue(glob->swap_queue);
    destroy_workqueue(glob->swap_queue);
    glob->swap_queue = NULL;
    for (i = 0; i < glob->num_zones; ++i) {
        zone = glob->zones[i];
        kobject_del(&zone->kobj);
        kobject_put(&zone->kobj);
            }
    kobject_del(&glob->kobj);
    kobject_put(&glob->kobj);
}
EXPORT_SYMBOL(ttm_mem_global_release);

static void ttm_check_swapping(struct ttm_mem_global *glob)
{
    bool needs_swapping = false;
    unsigned int i;
    struct ttm_mem_zone *zone;

    spin_lock(&glob->lock);
    for (i = 0; i < glob->num_zones; ++i) {
        zone = glob->zones[i];
        if (zone->used_mem > zone->swap_limit) {
            needs_swapping = true;
            break;
        }
    }

    spin_unlock(&glob->lock);

    if (unlikely(needs_swapping))
        (void)queue_work(glob->swap_queue, &glob->work);

}

static void ttm_mem_global_free_zone(struct ttm_mem_global *glob,
                     struct ttm_mem_zone *single_zone,
                     uint64_t amount)
{
    unsigned int i;
    struct ttm_mem_zone *zone;

    spin_lock(&glob->lock);
    for (i = 0; i < glob->num_zones; ++i) {
        zone = glob->zones[i];
        if (single_zone && zone != single_zone)
            continue;
        zone->used_mem -= amount;
    }
    spin_unlock(&glob->lock);
}

void ttm_mem_global_free(struct ttm_mem_global *glob,
             uint64_t amount)
{
    return ttm_mem_global_free_zone(glob, NULL, amount);
}
EXPORT_SYMBOL(ttm_mem_global_free);

static int ttm_mem_global_reserve(struct ttm_mem_global *glob,
                  struct ttm_mem_zone *single_zone,
                  uint64_t amount, bool reserve)
{
    uint64_t limit;
    int ret = -ENOMEM;
    unsigned int i;
    struct ttm_mem_zone *zone;

    spin_lock(&glob->lock);
    for (i = 0; i < glob->num_zones; ++i) {
        zone = glob->zones[i];
        if (single_zone && zone != single_zone)
            continue;

        limit = (capable(CAP_SYS_ADMIN)) ?
            zone->emer_mem : zone->max_mem;

        if (zone->used_mem > limit)
            goto out_unlock;
    }

    if (reserve) {
        for (i = 0; i < glob->num_zones; ++i) {
            zone = glob->zones[i];
            if (single_zone && zone != single_zone)
                continue;
            zone->used_mem += amount;
        }
    }

    ret = 0;
out_unlock:
    spin_unlock(&glob->lock);
    ttm_check_swapping(glob);

    return ret;
}


static int ttm_mem_global_alloc_zone(struct ttm_mem_global *glob,
                     struct ttm_mem_zone *single_zone,
                     uint64_t memory,
                     bool no_wait, bool interruptible)
{
    int count = TTM_MEMORY_ALLOC_RETRIES;

    while (unlikely(ttm_mem_global_reserve(glob,
                           single_zone,
                           memory, true)
            != 0)) {
        if (no_wait)
            return -ENOMEM;
        if (unlikely(count-- == 0))
            return -ENOMEM;
        ttm_shrink(glob, false, memory + (memory >> 2) + 16);
    }

    return 0;
}

int ttm_mem_global_alloc(struct ttm_mem_global *glob, uint64_t memory,
             bool no_wait, bool interruptible)
{
    return ttm_mem_global_alloc_zone(glob, NULL, memory, no_wait,
                     interruptible);
}
EXPORT_SYMBOL(ttm_mem_global_alloc);

int ttm_mem_global_alloc_page(struct ttm_mem_global *glob,
                  struct page *page,
                  bool no_wait, bool interruptible)
{

    struct ttm_mem_zone *zone = NULL;

#ifdef CONFIG_HIGHMEM
    if (PageHighMem(page) && glob->zone_highmem != NULL)
        zone = glob->zone_highmem;
#else
    if (glob->zone_dma32 && page_to_pfn(page) > 0x00100000UL)
        zone = glob->zone_kernel;
#endif
    return ttm_mem_global_alloc_zone(glob, zone, PAGE_SIZE, no_wait,
                     interruptible);
}

void ttm_mem_global_free_page(struct ttm_mem_global *glob, struct page *page)
{
    struct ttm_mem_zone *zone = NULL;

#ifdef CONFIG_HIGHMEM
    if (PageHighMem(page) && glob->zone_highmem != NULL)
        zone = glob->zone_highmem;
#else
    if (glob->zone_dma32 && page_to_pfn(page) > 0x00100000UL)
        zone = glob->zone_kernel;
#endif
    ttm_mem_global_free_zone(glob, zone, PAGE_SIZE);
}


size_t ttm_round_pot(size_t size)
{
    if ((size & (size - 1)) == 0)
        return size;
    else if (size > PAGE_SIZE)
        return PAGE_ALIGN(size);
    else {
        size_t tmp_size = 4;

        while (tmp_size < size)
            tmp_size <<= 1;

        return tmp_size;
    }
    return 0;
}
EXPORT_SYMBOL(ttm_round_pot);