Switch back to using a spinlock again by moving the IOMMU unmap outside of the locked region.
Signed-off-by: Christian König christian.koenig@amd.com --- drivers/gpu/drm/ttm/ttm_pool.c | 40 +++++++++++++++------------------- include/linux/shrinker.h | 1 + mm/vmscan.c | 10 +++++++++ 3 files changed, 29 insertions(+), 22 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_pool.c b/drivers/gpu/drm/ttm/ttm_pool.c index cb38b1a17b09..a8b4abe687ce 100644 --- a/drivers/gpu/drm/ttm/ttm_pool.c +++ b/drivers/gpu/drm/ttm/ttm_pool.c @@ -70,7 +70,7 @@ static struct ttm_pool_type global_uncached[MAX_ORDER]; static struct ttm_pool_type global_dma32_write_combined[MAX_ORDER]; static struct ttm_pool_type global_dma32_uncached[MAX_ORDER];
-static struct mutex shrinker_lock; +static spinlock_t shrinker_lock; static struct list_head shrinker_list; static struct shrinker mm_shrinker;
@@ -263,9 +263,9 @@ static void ttm_pool_type_init(struct ttm_pool_type *pt, struct ttm_pool *pool, spin_lock_init(&pt->lock); INIT_LIST_HEAD(&pt->pages);
- mutex_lock(&shrinker_lock); + spin_lock(&shrinker_lock); list_add_tail(&pt->shrinker_list, &shrinker_list); - mutex_unlock(&shrinker_lock); + spin_unlock(&shrinker_lock); }
/* Remove a pool_type from the global shrinker list and free all pages */ @@ -273,9 +273,9 @@ static void ttm_pool_type_fini(struct ttm_pool_type *pt) { struct page *p;
- mutex_lock(&shrinker_lock); + spin_lock(&shrinker_lock); list_del(&pt->shrinker_list); - mutex_unlock(&shrinker_lock); + spin_unlock(&shrinker_lock);
while ((p = ttm_pool_type_take(pt))) ttm_pool_free_page(pt->pool, pt->caching, pt->order, p); @@ -313,24 +313,19 @@ static struct ttm_pool_type *ttm_pool_select_type(struct ttm_pool *pool, static unsigned int ttm_pool_shrink(void) { struct ttm_pool_type *pt; - unsigned int num_freed; struct page *p;
- mutex_lock(&shrinker_lock); + spin_lock(&shrinker_lock); pt = list_first_entry(&shrinker_list, typeof(*pt), shrinker_list); + list_move_tail(&pt->shrinker_list, &shrinker_list); + spin_unlock(&shrinker_lock);
p = ttm_pool_type_take(pt); - if (p) { - ttm_pool_free_page(pt->pool, pt->caching, pt->order, p); - num_freed = 1 << pt->order; - } else { - num_freed = 0; - } - - list_move_tail(&pt->shrinker_list, &shrinker_list); - mutex_unlock(&shrinker_lock); + if (!p) + return 0;
- return num_freed; + ttm_pool_free_page(pt->pool, pt->caching, pt->order, p); + return 1 << pt->order; }
/* Return the allocation order based for a page */ @@ -530,6 +525,7 @@ void ttm_pool_fini(struct ttm_pool *pool) for (j = 0; j < MAX_ORDER; ++j) ttm_pool_type_fini(&pool->caching[i].orders[j]); } + sync_shrinkers(); }
/* As long as pages are available make sure to release at least one */ @@ -604,7 +600,7 @@ static int ttm_pool_debugfs_globals_show(struct seq_file *m, void *data) { ttm_pool_debugfs_header(m);
- mutex_lock(&shrinker_lock); + spin_lock(&shrinker_lock); seq_puts(m, "wc\t:"); ttm_pool_debugfs_orders(global_write_combined, m); seq_puts(m, "uc\t:"); @@ -613,7 +609,7 @@ static int ttm_pool_debugfs_globals_show(struct seq_file *m, void *data) ttm_pool_debugfs_orders(global_dma32_write_combined, m); seq_puts(m, "uc 32\t:"); ttm_pool_debugfs_orders(global_dma32_uncached, m); - mutex_unlock(&shrinker_lock); + spin_unlock(&shrinker_lock);
ttm_pool_debugfs_footer(m);
@@ -640,7 +636,7 @@ int ttm_pool_debugfs(struct ttm_pool *pool, struct seq_file *m)
ttm_pool_debugfs_header(m);
- mutex_lock(&shrinker_lock); + spin_lock(&shrinker_lock); for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i) { seq_puts(m, "DMA "); switch (i) { @@ -656,7 +652,7 @@ int ttm_pool_debugfs(struct ttm_pool *pool, struct seq_file *m) } ttm_pool_debugfs_orders(pool->caching[i].orders, m); } - mutex_unlock(&shrinker_lock); + spin_unlock(&shrinker_lock);
ttm_pool_debugfs_footer(m); return 0; @@ -693,7 +689,7 @@ int ttm_pool_mgr_init(unsigned long num_pages) if (!page_pool_size) page_pool_size = num_pages;
- mutex_init(&shrinker_lock); + spin_lock_init(&shrinker_lock); INIT_LIST_HEAD(&shrinker_list);
for (i = 0; i < MAX_ORDER; ++i) { diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h index 0f80123650e2..6b75dc372fce 100644 --- a/include/linux/shrinker.h +++ b/include/linux/shrinker.h @@ -92,4 +92,5 @@ extern void register_shrinker_prepared(struct shrinker *shrinker); extern int register_shrinker(struct shrinker *shrinker); extern void unregister_shrinker(struct shrinker *shrinker); extern void free_prealloced_shrinker(struct shrinker *shrinker); +extern void sync_shrinkers(void); #endif diff --git a/mm/vmscan.c b/mm/vmscan.c index 562e87cbd7a1..46cd9c215d73 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -408,6 +408,16 @@ void unregister_shrinker(struct shrinker *shrinker) } EXPORT_SYMBOL(unregister_shrinker);
+/** + * sync_shrinker - Wait for all running shrinkers to complete. + */ +void sync_shrinkers(void) +{ + down_write(&shrinker_rwsem); + up_write(&shrinker_rwsem); +} +EXPORT_SYMBOL(sync_shrinkers); + #define SHRINK_BATCH 128
static unsigned long do_shrink_slab(struct shrink_control *shrinkctl,
Hi "Christian,
I love your patch! Perhaps something to improve:
[auto build test WARNING on drm-tip/drm-tip] [also build test WARNING on drm-exynos/exynos-drm-next tegra-drm/drm/tegra/for-next next-20210401] [cannot apply to drm-intel/for-linux-next linus/master drm/drm-next v5.12-rc5] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Christian-K-nig/drm-ttm-optimize-th... base: git://anongit.freedesktop.org/drm/drm-tip drm-tip config: x86_64-randconfig-a004-20210401 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 1c268a8ff4e90a85d0e634350b1104080614cf2b) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu # https://github.com/0day-ci/linux/commit/c0f3e98ef4f78d5e9d874be1f339186faf5c... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Christian-K-nig/drm-ttm-optimize-the-pool-shrinker-a-bit/20210401-215623 git checkout c0f3e98ef4f78d5e9d874be1f339186faf5c60bc # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64
If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot lkp@intel.com
All warnings (new ones prefixed by >>):
mm/vmscan.c:415: warning: expecting prototype for sync_shrinker(). Prototype was for sync_shrinkers() instead
mm/vmscan.c:1627: warning: wrong kernel-doc identifier on line: * Isolating page from the lruvec to fill in @dst list by nr_to_scan times.
vim +415 mm/vmscan.c
410 411 /** 412 * sync_shrinker - Wait for all running shrinkers to complete. 413 */ 414 void sync_shrinkers(void)
415 {
416 down_write(&shrinker_rwsem); 417 up_write(&shrinker_rwsem); 418 } 419 EXPORT_SYMBOL(sync_shrinkers); 420
--- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
On Thu, Apr 01, 2021 at 03:54:13PM +0200, Christian König wrote:
Switch back to using a spinlock again by moving the IOMMU unmap outside of the locked region.
Signed-off-by: Christian König christian.koenig@amd.com
drivers/gpu/drm/ttm/ttm_pool.c | 40 +++++++++++++++------------------- include/linux/shrinker.h | 1 + mm/vmscan.c | 10 +++++++++ 3 files changed, 29 insertions(+), 22 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_pool.c b/drivers/gpu/drm/ttm/ttm_pool.c index cb38b1a17b09..a8b4abe687ce 100644 --- a/drivers/gpu/drm/ttm/ttm_pool.c +++ b/drivers/gpu/drm/ttm/ttm_pool.c @@ -70,7 +70,7 @@ static struct ttm_pool_type global_uncached[MAX_ORDER]; static struct ttm_pool_type global_dma32_write_combined[MAX_ORDER]; static struct ttm_pool_type global_dma32_uncached[MAX_ORDER];
-static struct mutex shrinker_lock; +static spinlock_t shrinker_lock; static struct list_head shrinker_list; static struct shrinker mm_shrinker;
@@ -263,9 +263,9 @@ static void ttm_pool_type_init(struct ttm_pool_type *pt, struct ttm_pool *pool, spin_lock_init(&pt->lock); INIT_LIST_HEAD(&pt->pages);
- mutex_lock(&shrinker_lock);
- spin_lock(&shrinker_lock); list_add_tail(&pt->shrinker_list, &shrinker_list);
- mutex_unlock(&shrinker_lock);
- spin_unlock(&shrinker_lock);
}
/* Remove a pool_type from the global shrinker list and free all pages */ @@ -273,9 +273,9 @@ static void ttm_pool_type_fini(struct ttm_pool_type *pt) { struct page *p;
- mutex_lock(&shrinker_lock);
- spin_lock(&shrinker_lock); list_del(&pt->shrinker_list);
- mutex_unlock(&shrinker_lock);
spin_unlock(&shrinker_lock);
while ((p = ttm_pool_type_take(pt))) ttm_pool_free_page(pt->pool, pt->caching, pt->order, p);
@@ -313,24 +313,19 @@ static struct ttm_pool_type *ttm_pool_select_type(struct ttm_pool *pool, static unsigned int ttm_pool_shrink(void) { struct ttm_pool_type *pt;
unsigned int num_freed; struct page *p;
mutex_lock(&shrinker_lock);
spin_lock(&shrinker_lock); pt = list_first_entry(&shrinker_list, typeof(*pt), shrinker_list);
list_move_tail(&pt->shrinker_list, &shrinker_list);
spin_unlock(&shrinker_lock);
p = ttm_pool_type_take(pt);
- if (p) {
ttm_pool_free_page(pt->pool, pt->caching, pt->order, p);num_freed = 1 << pt->order;- } else {
num_freed = 0;- }
- list_move_tail(&pt->shrinker_list, &shrinker_list);
- mutex_unlock(&shrinker_lock);
- if (!p)
return 0;
- return num_freed;
- ttm_pool_free_page(pt->pool, pt->caching, pt->order, p);
- return 1 << pt->order;
}
/* Return the allocation order based for a page */ @@ -530,6 +525,7 @@ void ttm_pool_fini(struct ttm_pool *pool) for (j = 0; j < MAX_ORDER; ++j) ttm_pool_type_fini(&pool->caching[i].orders[j]); }
- sync_shrinkers();
}
/* As long as pages are available make sure to release at least one */ @@ -604,7 +600,7 @@ static int ttm_pool_debugfs_globals_show(struct seq_file *m, void *data) { ttm_pool_debugfs_header(m);
- mutex_lock(&shrinker_lock);
- spin_lock(&shrinker_lock); seq_puts(m, "wc\t:"); ttm_pool_debugfs_orders(global_write_combined, m); seq_puts(m, "uc\t:");
@@ -613,7 +609,7 @@ static int ttm_pool_debugfs_globals_show(struct seq_file *m, void *data) ttm_pool_debugfs_orders(global_dma32_write_combined, m); seq_puts(m, "uc 32\t:"); ttm_pool_debugfs_orders(global_dma32_uncached, m);
- mutex_unlock(&shrinker_lock);
spin_unlock(&shrinker_lock);
ttm_pool_debugfs_footer(m);
@@ -640,7 +636,7 @@ int ttm_pool_debugfs(struct ttm_pool *pool, struct seq_file *m)
ttm_pool_debugfs_header(m);
- mutex_lock(&shrinker_lock);
- spin_lock(&shrinker_lock); for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i) { seq_puts(m, "DMA "); switch (i) {
@@ -656,7 +652,7 @@ int ttm_pool_debugfs(struct ttm_pool *pool, struct seq_file *m) } ttm_pool_debugfs_orders(pool->caching[i].orders, m); }
- mutex_unlock(&shrinker_lock);
spin_unlock(&shrinker_lock);
ttm_pool_debugfs_footer(m); return 0;
@@ -693,7 +689,7 @@ int ttm_pool_mgr_init(unsigned long num_pages) if (!page_pool_size) page_pool_size = num_pages;
- mutex_init(&shrinker_lock);
spin_lock_init(&shrinker_lock); INIT_LIST_HEAD(&shrinker_list);
for (i = 0; i < MAX_ORDER; ++i) {
diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h index 0f80123650e2..6b75dc372fce 100644 --- a/include/linux/shrinker.h +++ b/include/linux/shrinker.h @@ -92,4 +92,5 @@ extern void register_shrinker_prepared(struct shrinker *shrinker); extern int register_shrinker(struct shrinker *shrinker); extern void unregister_shrinker(struct shrinker *shrinker); extern void free_prealloced_shrinker(struct shrinker *shrinker); +extern void sync_shrinkers(void); #endif diff --git a/mm/vmscan.c b/mm/vmscan.c index 562e87cbd7a1..46cd9c215d73 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -408,6 +408,16 @@ void unregister_shrinker(struct shrinker *shrinker) } EXPORT_SYMBOL(unregister_shrinker);
+/**
- sync_shrinker - Wait for all running shrinkers to complete.
- */
+void sync_shrinkers(void)
This one should probably be in its own patch, with a bit more commit message about why we need it and all that. I'd assume that just unregistering the shrinker should sync everything we needed to sync already, and for other sync needs we can do locking within our own shrinker? -Daniel
+{
- down_write(&shrinker_rwsem);
- up_write(&shrinker_rwsem);
+} +EXPORT_SYMBOL(sync_shrinkers);
#define SHRINK_BATCH 128
static unsigned long do_shrink_slab(struct shrink_control *shrinkctl,
2.25.1
Am 08.04.21 um 13:08 schrieb Daniel Vetter:
On Thu, Apr 01, 2021 at 03:54:13PM +0200, Christian König wrote:
Switch back to using a spinlock again by moving the IOMMU unmap outside of the locked region.
Signed-off-by: Christian König christian.koenig@amd.com
drivers/gpu/drm/ttm/ttm_pool.c | 40 +++++++++++++++------------------- include/linux/shrinker.h | 1 + mm/vmscan.c | 10 +++++++++ 3 files changed, 29 insertions(+), 22 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_pool.c b/drivers/gpu/drm/ttm/ttm_pool.c index cb38b1a17b09..a8b4abe687ce 100644 --- a/drivers/gpu/drm/ttm/ttm_pool.c +++ b/drivers/gpu/drm/ttm/ttm_pool.c @@ -70,7 +70,7 @@ static struct ttm_pool_type global_uncached[MAX_ORDER]; static struct ttm_pool_type global_dma32_write_combined[MAX_ORDER]; static struct ttm_pool_type global_dma32_uncached[MAX_ORDER];
-static struct mutex shrinker_lock; +static spinlock_t shrinker_lock; static struct list_head shrinker_list; static struct shrinker mm_shrinker;
@@ -263,9 +263,9 @@ static void ttm_pool_type_init(struct ttm_pool_type *pt, struct ttm_pool *pool, spin_lock_init(&pt->lock); INIT_LIST_HEAD(&pt->pages);
- mutex_lock(&shrinker_lock);
- spin_lock(&shrinker_lock); list_add_tail(&pt->shrinker_list, &shrinker_list);
- mutex_unlock(&shrinker_lock);
spin_unlock(&shrinker_lock); }
/* Remove a pool_type from the global shrinker list and free all pages */
@@ -273,9 +273,9 @@ static void ttm_pool_type_fini(struct ttm_pool_type *pt) { struct page *p;
- mutex_lock(&shrinker_lock);
- spin_lock(&shrinker_lock); list_del(&pt->shrinker_list);
- mutex_unlock(&shrinker_lock);
spin_unlock(&shrinker_lock);
while ((p = ttm_pool_type_take(pt))) ttm_pool_free_page(pt->pool, pt->caching, pt->order, p);
@@ -313,24 +313,19 @@ static struct ttm_pool_type *ttm_pool_select_type(struct ttm_pool *pool, static unsigned int ttm_pool_shrink(void) { struct ttm_pool_type *pt;
unsigned int num_freed; struct page *p;
mutex_lock(&shrinker_lock);
spin_lock(&shrinker_lock); pt = list_first_entry(&shrinker_list, typeof(*pt), shrinker_list);
list_move_tail(&pt->shrinker_list, &shrinker_list);
spin_unlock(&shrinker_lock);
p = ttm_pool_type_take(pt);
- if (p) {
ttm_pool_free_page(pt->pool, pt->caching, pt->order, p);num_freed = 1 << pt->order;- } else {
num_freed = 0;- }
- list_move_tail(&pt->shrinker_list, &shrinker_list);
- mutex_unlock(&shrinker_lock);
- if (!p)
return 0;
- return num_freed;
ttm_pool_free_page(pt->pool, pt->caching, pt->order, p);
return 1 << pt->order; }
/* Return the allocation order based for a page */
@@ -530,6 +525,7 @@ void ttm_pool_fini(struct ttm_pool *pool) for (j = 0; j < MAX_ORDER; ++j) ttm_pool_type_fini(&pool->caching[i].orders[j]); }
sync_shrinkers(); }
/* As long as pages are available make sure to release at least one */
@@ -604,7 +600,7 @@ static int ttm_pool_debugfs_globals_show(struct seq_file *m, void *data) { ttm_pool_debugfs_header(m);
- mutex_lock(&shrinker_lock);
- spin_lock(&shrinker_lock); seq_puts(m, "wc\t:"); ttm_pool_debugfs_orders(global_write_combined, m); seq_puts(m, "uc\t:");
@@ -613,7 +609,7 @@ static int ttm_pool_debugfs_globals_show(struct seq_file *m, void *data) ttm_pool_debugfs_orders(global_dma32_write_combined, m); seq_puts(m, "uc 32\t:"); ttm_pool_debugfs_orders(global_dma32_uncached, m);
- mutex_unlock(&shrinker_lock);
spin_unlock(&shrinker_lock);
ttm_pool_debugfs_footer(m);
@@ -640,7 +636,7 @@ int ttm_pool_debugfs(struct ttm_pool *pool, struct seq_file *m)
ttm_pool_debugfs_header(m);
- mutex_lock(&shrinker_lock);
- spin_lock(&shrinker_lock); for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i) { seq_puts(m, "DMA "); switch (i) {
@@ -656,7 +652,7 @@ int ttm_pool_debugfs(struct ttm_pool *pool, struct seq_file *m) } ttm_pool_debugfs_orders(pool->caching[i].orders, m); }
- mutex_unlock(&shrinker_lock);
spin_unlock(&shrinker_lock);
ttm_pool_debugfs_footer(m); return 0;
@@ -693,7 +689,7 @@ int ttm_pool_mgr_init(unsigned long num_pages) if (!page_pool_size) page_pool_size = num_pages;
- mutex_init(&shrinker_lock);
spin_lock_init(&shrinker_lock); INIT_LIST_HEAD(&shrinker_list);
for (i = 0; i < MAX_ORDER; ++i) {
diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h index 0f80123650e2..6b75dc372fce 100644 --- a/include/linux/shrinker.h +++ b/include/linux/shrinker.h @@ -92,4 +92,5 @@ extern void register_shrinker_prepared(struct shrinker *shrinker); extern int register_shrinker(struct shrinker *shrinker); extern void unregister_shrinker(struct shrinker *shrinker); extern void free_prealloced_shrinker(struct shrinker *shrinker); +extern void sync_shrinkers(void); #endif diff --git a/mm/vmscan.c b/mm/vmscan.c index 562e87cbd7a1..46cd9c215d73 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -408,6 +408,16 @@ void unregister_shrinker(struct shrinker *shrinker) } EXPORT_SYMBOL(unregister_shrinker);
+/**
- sync_shrinker - Wait for all running shrinkers to complete.
- */
+void sync_shrinkers(void)
This one should probably be in its own patch, with a bit more commit message about why we need it and all that. I'd assume that just unregistering the shrinker should sync everything we needed to sync already, and for other sync needs we can do locking within our own shrinker?
Correct. Reason why we need the barrier is that we need to destroy the device (during hotplug) before the shrinker is unregistered (during module unload).
Going to separate that, write something up in the commit message and send it to the appropriate audience.
Thanks, Christian.
-Daniel
+{
- down_write(&shrinker_rwsem);
- up_write(&shrinker_rwsem);
+} +EXPORT_SYMBOL(sync_shrinkers);
#define SHRINK_BATCH 128
static unsigned long do_shrink_slab(struct shrink_control *shrinkctl,
-- 2.25.1
On Thu, Apr 08, 2021 at 01:17:32PM +0200, Christian König wrote:
Am 08.04.21 um 13:08 schrieb Daniel Vetter:
On Thu, Apr 01, 2021 at 03:54:13PM +0200, Christian König wrote:
Switch back to using a spinlock again by moving the IOMMU unmap outside of the locked region.
Signed-off-by: Christian König christian.koenig@amd.com
drivers/gpu/drm/ttm/ttm_pool.c | 40 +++++++++++++++------------------- include/linux/shrinker.h | 1 + mm/vmscan.c | 10 +++++++++ 3 files changed, 29 insertions(+), 22 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_pool.c b/drivers/gpu/drm/ttm/ttm_pool.c index cb38b1a17b09..a8b4abe687ce 100644 --- a/drivers/gpu/drm/ttm/ttm_pool.c +++ b/drivers/gpu/drm/ttm/ttm_pool.c @@ -70,7 +70,7 @@ static struct ttm_pool_type global_uncached[MAX_ORDER]; static struct ttm_pool_type global_dma32_write_combined[MAX_ORDER]; static struct ttm_pool_type global_dma32_uncached[MAX_ORDER]; -static struct mutex shrinker_lock; +static spinlock_t shrinker_lock; static struct list_head shrinker_list; static struct shrinker mm_shrinker; @@ -263,9 +263,9 @@ static void ttm_pool_type_init(struct ttm_pool_type *pt, struct ttm_pool *pool, spin_lock_init(&pt->lock); INIT_LIST_HEAD(&pt->pages);
- mutex_lock(&shrinker_lock);
- spin_lock(&shrinker_lock); list_add_tail(&pt->shrinker_list, &shrinker_list);
- mutex_unlock(&shrinker_lock);
- spin_unlock(&shrinker_lock); } /* Remove a pool_type from the global shrinker list and free all pages */
@@ -273,9 +273,9 @@ static void ttm_pool_type_fini(struct ttm_pool_type *pt) { struct page *p;
- mutex_lock(&shrinker_lock);
- spin_lock(&shrinker_lock); list_del(&pt->shrinker_list);
- mutex_unlock(&shrinker_lock);
- spin_unlock(&shrinker_lock); while ((p = ttm_pool_type_take(pt))) ttm_pool_free_page(pt->pool, pt->caching, pt->order, p);
@@ -313,24 +313,19 @@ static struct ttm_pool_type *ttm_pool_select_type(struct ttm_pool *pool, static unsigned int ttm_pool_shrink(void) { struct ttm_pool_type *pt;
- unsigned int num_freed; struct page *p;
- mutex_lock(&shrinker_lock);
- spin_lock(&shrinker_lock); pt = list_first_entry(&shrinker_list, typeof(*pt), shrinker_list);
- list_move_tail(&pt->shrinker_list, &shrinker_list);
- spin_unlock(&shrinker_lock); p = ttm_pool_type_take(pt);
- if (p) {
ttm_pool_free_page(pt->pool, pt->caching, pt->order, p);num_freed = 1 << pt->order;- } else {
num_freed = 0;- }
- list_move_tail(&pt->shrinker_list, &shrinker_list);
- mutex_unlock(&shrinker_lock);
- if (!p)
return 0;
- return num_freed;
- ttm_pool_free_page(pt->pool, pt->caching, pt->order, p);
- return 1 << pt->order; } /* Return the allocation order based for a page */
@@ -530,6 +525,7 @@ void ttm_pool_fini(struct ttm_pool *pool) for (j = 0; j < MAX_ORDER; ++j) ttm_pool_type_fini(&pool->caching[i].orders[j]); }
- sync_shrinkers(); } /* As long as pages are available make sure to release at least one */
@@ -604,7 +600,7 @@ static int ttm_pool_debugfs_globals_show(struct seq_file *m, void *data) { ttm_pool_debugfs_header(m);
- mutex_lock(&shrinker_lock);
- spin_lock(&shrinker_lock); seq_puts(m, "wc\t:"); ttm_pool_debugfs_orders(global_write_combined, m); seq_puts(m, "uc\t:");
@@ -613,7 +609,7 @@ static int ttm_pool_debugfs_globals_show(struct seq_file *m, void *data) ttm_pool_debugfs_orders(global_dma32_write_combined, m); seq_puts(m, "uc 32\t:"); ttm_pool_debugfs_orders(global_dma32_uncached, m);
- mutex_unlock(&shrinker_lock);
- spin_unlock(&shrinker_lock); ttm_pool_debugfs_footer(m);
@@ -640,7 +636,7 @@ int ttm_pool_debugfs(struct ttm_pool *pool, struct seq_file *m) ttm_pool_debugfs_header(m);
- mutex_lock(&shrinker_lock);
- spin_lock(&shrinker_lock); for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i) { seq_puts(m, "DMA "); switch (i) {
@@ -656,7 +652,7 @@ int ttm_pool_debugfs(struct ttm_pool *pool, struct seq_file *m) } ttm_pool_debugfs_orders(pool->caching[i].orders, m); }
- mutex_unlock(&shrinker_lock);
- spin_unlock(&shrinker_lock); ttm_pool_debugfs_footer(m); return 0;
@@ -693,7 +689,7 @@ int ttm_pool_mgr_init(unsigned long num_pages) if (!page_pool_size) page_pool_size = num_pages;
- mutex_init(&shrinker_lock);
- spin_lock_init(&shrinker_lock); INIT_LIST_HEAD(&shrinker_list); for (i = 0; i < MAX_ORDER; ++i) {
diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h index 0f80123650e2..6b75dc372fce 100644 --- a/include/linux/shrinker.h +++ b/include/linux/shrinker.h @@ -92,4 +92,5 @@ extern void register_shrinker_prepared(struct shrinker *shrinker); extern int register_shrinker(struct shrinker *shrinker); extern void unregister_shrinker(struct shrinker *shrinker); extern void free_prealloced_shrinker(struct shrinker *shrinker); +extern void sync_shrinkers(void); #endif diff --git a/mm/vmscan.c b/mm/vmscan.c index 562e87cbd7a1..46cd9c215d73 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -408,6 +408,16 @@ void unregister_shrinker(struct shrinker *shrinker) } EXPORT_SYMBOL(unregister_shrinker); +/**
- sync_shrinker - Wait for all running shrinkers to complete.
- */
+void sync_shrinkers(void)
This one should probably be in its own patch, with a bit more commit message about why we need it and all that. I'd assume that just unregistering the shrinker should sync everything we needed to sync already, and for other sync needs we can do locking within our own shrinker?
Correct. Reason why we need the barrier is that we need to destroy the device (during hotplug) before the shrinker is unregistered (during module unload).
Going to separate that, write something up in the commit message and send it to the appropriate audience.
Hm why do we need that? Either way sounds like an orthogonal series for the hotunplug work, not just shrinker optimization. -Daniel
Thanks, Christian.
-Daniel
+{
- down_write(&shrinker_rwsem);
- up_write(&shrinker_rwsem);
+} +EXPORT_SYMBOL(sync_shrinkers);
- #define SHRINK_BATCH 128 static unsigned long do_shrink_slab(struct shrink_control *shrinkctl,
-- 2.25.1
Am 08.04.21 um 13:31 schrieb Daniel Vetter:
On Thu, Apr 08, 2021 at 01:17:32PM +0200, Christian König wrote:
Am 08.04.21 um 13:08 schrieb Daniel Vetter:
On Thu, Apr 01, 2021 at 03:54:13PM +0200, Christian König wrote:
[SNIP] EXPORT_SYMBOL(unregister_shrinker); +/**
- sync_shrinker - Wait for all running shrinkers to complete.
- */
+void sync_shrinkers(void)
This one should probably be in its own patch, with a bit more commit message about why we need it and all that. I'd assume that just unregistering the shrinker should sync everything we needed to sync already, and for other sync needs we can do locking within our own shrinker?
Correct. Reason why we need the barrier is that we need to destroy the device (during hotplug) before the shrinker is unregistered (during module unload).
Going to separate that, write something up in the commit message and send it to the appropriate audience.
Hm why do we need that?
When the shrinker runs in parallel with (for example) a hotplug event and unmaps pages from the devices IOMMU I must make sure that you can't destroy the device or pool structure at the same time.
Previously holding the mutex while updating the IOMMU would take care of that, but now we need to prevent this otherwise.
Could be that this is also handled somewhere else, but I'm better save than sorry here and grabbing/releasing write side of the shrinker_rwsem is rather lightweight.
Either way sounds like an orthogonal series for the hotunplug work, not just shrinker optimization.
It is unrelated to the hotplug work in general.
Regards, Christian.
-Daniel
Thanks, Christian.
-Daniel
+{
- down_write(&shrinker_rwsem);
- up_write(&shrinker_rwsem);
+} +EXPORT_SYMBOL(sync_shrinkers);
- #define SHRINK_BATCH 128 static unsigned long do_shrink_slab(struct shrink_control *shrinkctl,
-- 2.25.1
On Thu, Apr 08, 2021 at 02:44:16PM +0200, Christian König wrote:
Am 08.04.21 um 13:31 schrieb Daniel Vetter:
On Thu, Apr 08, 2021 at 01:17:32PM +0200, Christian König wrote:
Am 08.04.21 um 13:08 schrieb Daniel Vetter:
On Thu, Apr 01, 2021 at 03:54:13PM +0200, Christian König wrote:
[SNIP] EXPORT_SYMBOL(unregister_shrinker); +/**
- sync_shrinker - Wait for all running shrinkers to complete.
- */
+void sync_shrinkers(void)
This one should probably be in its own patch, with a bit more commit message about why we need it and all that. I'd assume that just unregistering the shrinker should sync everything we needed to sync already, and for other sync needs we can do locking within our own shrinker?
Correct. Reason why we need the barrier is that we need to destroy the device (during hotplug) before the shrinker is unregistered (during module unload).
Going to separate that, write something up in the commit message and send it to the appropriate audience.
Hm why do we need that?
When the shrinker runs in parallel with (for example) a hotplug event and unmaps pages from the devices IOMMU I must make sure that you can't destroy the device or pool structure at the same time.
Previously holding the mutex while updating the IOMMU would take care of that, but now we need to prevent this otherwise.
Could be that this is also handled somewhere else, but I'm better save than sorry here and grabbing/releasing write side of the shrinker_rwsem is rather lightweight.
I forgot that we don't have a per-pool (or at least per-device) shrinker, but one global one for all ttm device. So yeah with that design a sync_shrinker is needed. -Daniel
Either way sounds like an orthogonal series for the hotunplug work, not just shrinker optimization.
It is unrelated to the hotplug work in general.
Regards, Christian.
-Daniel
Thanks, Christian.
-Daniel
+{
- down_write(&shrinker_rwsem);
- up_write(&shrinker_rwsem);
+} +EXPORT_SYMBOL(sync_shrinkers);
- #define SHRINK_BATCH 128 static unsigned long do_shrink_slab(struct shrink_control *shrinkctl,
-- 2.25.1
dri-devel@lists.freedesktop.org
-
Christian König -
Daniel Vetter -
kernel test robot