[3.13.y.z extended stable] Patch "drm/ttm: Pass GFP flags in order to avoid deadlock." has been added to staging queue
Kamal Mostafa
kamal at canonical.com
Mon Sep 15 22:07:58 UTC 2014
This is a note to let you know that I have just added a patch titled
drm/ttm: Pass GFP flags in order to avoid deadlock.
to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree
which can be found at:
http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue
This patch is scheduled to be released in version 3.13.11.7.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Kamal
------
>From 3dd74d70b559eaed5853089da72c8dbfdff5e113 Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel at I-love.SAKURA.ne.jp>
Date: Sun, 3 Aug 2014 20:02:31 +0900
Subject: drm/ttm: Pass GFP flags in order to avoid deadlock.
commit a91576d7916f6cce76d30303e60e1ac47cf4a76d upstream.
Commit 7dc19d5a "drivers: convert shrinkers to new count/scan API" added
deadlock warnings that ttm_page_pool_free() and ttm_dma_page_pool_free()
are currently doing GFP_KERNEL allocation.
But these functions did not get updated to receive gfp_t argument.
This patch explicitly passes sc->gfp_mask or GFP_KERNEL to these functions,
and removes the deadlock warning.
Signed-off-by: Tetsuo Handa <penguin-kernel at I-love.SAKURA.ne.jp>
Signed-off-by: Dave Airlie <airlied at redhat.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
drivers/gpu/drm/ttm/ttm_page_alloc.c | 19 ++++++++++---------
drivers/gpu/drm/ttm/ttm_page_alloc_dma.c | 19 +++++++++----------
2 files changed, 19 insertions(+), 19 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc.c b/drivers/gpu/drm/ttm/ttm_page_alloc.c
index deba59b..cf4bad2 100644
--- a/drivers/gpu/drm/ttm/ttm_page_alloc.c
+++ b/drivers/gpu/drm/ttm/ttm_page_alloc.c
@@ -297,8 +297,10 @@ static void ttm_pool_update_free_locked(struct ttm_page_pool *pool,
*
* @pool: to free the pages from
* @free_all: If set to true will free all pages in pool
+ * @gfp: GFP flags.
**/
-static int ttm_page_pool_free(struct ttm_page_pool *pool, unsigned nr_free)
+static int ttm_page_pool_free(struct ttm_page_pool *pool, unsigned nr_free,
+ gfp_t gfp)
{
unsigned long irq_flags;
struct page *p;
@@ -309,8 +311,7 @@ static int ttm_page_pool_free(struct ttm_page_pool *pool, unsigned nr_free)
if (NUM_PAGES_TO_ALLOC < nr_free)
npages_to_free = NUM_PAGES_TO_ALLOC;
- pages_to_free = kmalloc(npages_to_free * sizeof(struct page *),
- GFP_KERNEL);
+ pages_to_free = kmalloc(npages_to_free * sizeof(struct page *), gfp);
if (!pages_to_free) {
pr_err("Failed to allocate memory for pool free operation\n");
return 0;
@@ -382,9 +383,7 @@ out:
*
* XXX: (dchinner) Deadlock warning!
*
- * ttm_page_pool_free() does memory allocation using GFP_KERNEL. that means
- * this can deadlock when called a sc->gfp_mask that is not equal to
- * GFP_KERNEL.
+ * We need to pass sc->gfp_mask to ttm_page_pool_free().
*
* This code is crying out for a shrinker per pool....
*/
@@ -408,7 +407,8 @@ ttm_pool_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
if (shrink_pages == 0)
break;
pool = &_manager->pools[(i + pool_offset)%NUM_POOLS];
- shrink_pages = ttm_page_pool_free(pool, nr_free);
+ shrink_pages = ttm_page_pool_free(pool, nr_free,
+ sc->gfp_mask);
freed += nr_free - shrink_pages;
}
mutex_unlock(&lock);
@@ -710,7 +710,7 @@ static void ttm_put_pages(struct page **pages, unsigned npages, int flags,
}
spin_unlock_irqrestore(&pool->lock, irq_flags);
if (npages)
- ttm_page_pool_free(pool, npages);
+ ttm_page_pool_free(pool, npages, GFP_KERNEL);
}
/*
@@ -850,7 +850,8 @@ void ttm_page_alloc_fini(void)
ttm_pool_mm_shrink_fini(_manager);
for (i = 0; i < NUM_POOLS; ++i)
- ttm_page_pool_free(&_manager->pools[i], FREE_ALL_PAGES);
+ ttm_page_pool_free(&_manager->pools[i], FREE_ALL_PAGES,
+ GFP_KERNEL);
kobject_put(&_manager->kobj);
_manager = NULL;
diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
index 524cc1a..ca65df1 100644
--- a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
+++ b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
@@ -411,8 +411,10 @@ static void ttm_dma_page_put(struct dma_pool *pool, struct dma_page *d_page)
*
* @pool: to free the pages from
* @nr_free: If set to true will free all pages in pool
+ * @gfp: GFP flags.
**/
-static unsigned ttm_dma_page_pool_free(struct dma_pool *pool, unsigned nr_free)
+static unsigned ttm_dma_page_pool_free(struct dma_pool *pool, unsigned nr_free,
+ gfp_t gfp)
{
unsigned long irq_flags;
struct dma_page *dma_p, *tmp;
@@ -430,8 +432,7 @@ static unsigned ttm_dma_page_pool_free(struct dma_pool *pool, unsigned nr_free)
npages_to_free, nr_free);
}
#endif
- pages_to_free = kmalloc(npages_to_free * sizeof(struct page *),
- GFP_KERNEL);
+ pages_to_free = kmalloc(npages_to_free * sizeof(struct page *), gfp);
if (!pages_to_free) {
pr_err("%s: Failed to allocate memory for pool free operation\n",
@@ -530,7 +531,7 @@ static void ttm_dma_free_pool(struct device *dev, enum pool_type type)
if (pool->type != type)
continue;
/* Takes a spinlock.. */
- ttm_dma_page_pool_free(pool, FREE_ALL_PAGES);
+ ttm_dma_page_pool_free(pool, FREE_ALL_PAGES, GFP_KERNEL);
WARN_ON(((pool->npages_in_use + pool->npages_free) != 0));
/* This code path is called after _all_ references to the
* struct device has been dropped - so nobody should be
@@ -983,7 +984,7 @@ void ttm_dma_unpopulate(struct ttm_dma_tt *ttm_dma, struct device *dev)
/* shrink pool if necessary (only on !is_cached pools)*/
if (npages)
- ttm_dma_page_pool_free(pool, npages);
+ ttm_dma_page_pool_free(pool, npages, GFP_KERNEL);
ttm->state = tt_unpopulated;
}
EXPORT_SYMBOL_GPL(ttm_dma_unpopulate);
@@ -993,10 +994,7 @@ EXPORT_SYMBOL_GPL(ttm_dma_unpopulate);
*
* XXX: (dchinner) Deadlock warning!
*
- * ttm_dma_page_pool_free() does GFP_KERNEL memory allocation, and so attention
- * needs to be paid to sc->gfp_mask to determine if this can be done or not.
- * GFP_KERNEL memory allocation in a GFP_ATOMIC reclaim context woul dbe really
- * bad.
+ * We need to pass sc->gfp_mask to ttm_dma_page_pool_free().
*
* I'm getting sadder as I hear more pathetical whimpers about needing per-pool
* shrinkers
@@ -1030,7 +1028,8 @@ ttm_dma_pool_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
if (++idx < pool_offset)
continue;
nr_free = shrink_pages;
- shrink_pages = ttm_dma_page_pool_free(p->pool, nr_free);
+ shrink_pages = ttm_dma_page_pool_free(p->pool, nr_free,
+ sc->gfp_mask);
freed += nr_free - shrink_pages;
pr_debug("%s: (%s:%d) Asked to shrink %d, have %d more to go\n",
--
1.9.1
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