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authorDennis Zhou <dennisszhou@gmail.com>2018-02-16 12:09:58 -0600
committerTejun Heo <tj@kernel.org>2018-02-18 05:33:01 -0800
commit554fef1c39ee148623a496e04569dabb11463406 (patch)
treef1d187aad200c97bdf4b0b9f2c1c66735deab08a
parent47504ee04b9241548ae2c28be7d0b01cff3b7aa6 (diff)
downloadlinux-554fef1c39ee148623a496e04569dabb11463406.tar.bz2
percpu: allow select gfp to be passed to underlying allocators
The prior patch added support for passing gfp flags through to the underlying allocators. This patch allows users to pass along gfp flags (currently only __GFP_NORETRY and __GFP_NOWARN) to the underlying allocators. This should allow users to decide if they are ok with failing allocations recovering in a more graceful way. Additionally, gfp passing was done as additional flags in the previous patch. Instead, change this to caller passed semantics. GFP_KERNEL is also removed as the default flag. It continues to be used for internally caused underlying percpu allocations. V2: Removed gfp_percpu_mask in favor of doing it inline. Removed GFP_KERNEL as a default flag for __alloc_percpu_gfp. Signed-off-by: Dennis Zhou <dennisszhou@gmail.com> Suggested-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Christoph Lameter <cl@linux.com> Signed-off-by: Tejun Heo <tj@kernel.org>
-rw-r--r--mm/percpu-km.c2
-rw-r--r--mm/percpu-vm.c4
-rw-r--r--mm/percpu.c16
3 files changed, 10 insertions, 12 deletions
diff --git a/mm/percpu-km.c b/mm/percpu-km.c
index 0d88d7bd5706..38de70ab1a0d 100644
--- a/mm/percpu-km.c
+++ b/mm/percpu-km.c
@@ -56,7 +56,7 @@ static struct pcpu_chunk *pcpu_create_chunk(gfp_t gfp)
if (!chunk)
return NULL;
- pages = alloc_pages(gfp | GFP_KERNEL, order_base_2(nr_pages));
+ pages = alloc_pages(gfp, order_base_2(nr_pages));
if (!pages) {
pcpu_free_chunk(chunk);
return NULL;
diff --git a/mm/percpu-vm.c b/mm/percpu-vm.c
index 0af71eb2fff0..d8078de912de 100644
--- a/mm/percpu-vm.c
+++ b/mm/percpu-vm.c
@@ -37,7 +37,7 @@ static struct page **pcpu_get_pages(void)
lockdep_assert_held(&pcpu_alloc_mutex);
if (!pages)
- pages = pcpu_mem_zalloc(pages_size, 0);
+ pages = pcpu_mem_zalloc(pages_size, GFP_KERNEL);
return pages;
}
@@ -86,7 +86,7 @@ static int pcpu_alloc_pages(struct pcpu_chunk *chunk,
unsigned int cpu, tcpu;
int i;
- gfp |= GFP_KERNEL | __GFP_HIGHMEM;
+ gfp |= __GFP_HIGHMEM;
for_each_possible_cpu(cpu) {
for (i = page_start; i < page_end; i++) {
diff --git a/mm/percpu.c b/mm/percpu.c
index f97443d488a8..fa3f854634a1 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -454,9 +454,6 @@ static void pcpu_next_fit_region(struct pcpu_chunk *chunk, int alloc_bits,
* This is to facilitate passing through whitelisted flags. The
* returned memory is always zeroed.
*
- * CONTEXT:
- * Does GFP_KERNEL allocation.
- *
* RETURNS:
* Pointer to the allocated area on success, NULL on failure.
*/
@@ -466,10 +463,9 @@ static void *pcpu_mem_zalloc(size_t size, gfp_t gfp)
return NULL;
if (size <= PAGE_SIZE)
- return kzalloc(size, gfp | GFP_KERNEL);
+ return kzalloc(size, gfp);
else
- return __vmalloc(size, gfp | GFP_KERNEL | __GFP_ZERO,
- PAGE_KERNEL);
+ return __vmalloc(size, gfp | __GFP_ZERO, PAGE_KERNEL);
}
/**
@@ -1344,6 +1340,8 @@ static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved,
gfp_t gfp)
{
+ /* whitelisted flags that can be passed to the backing allocators */
+ gfp_t pcpu_gfp = gfp & (GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN);
bool is_atomic = (gfp & GFP_KERNEL) != GFP_KERNEL;
bool do_warn = !(gfp & __GFP_NOWARN);
static int warn_limit = 10;
@@ -1426,7 +1424,7 @@ restart:
}
if (list_empty(&pcpu_slot[pcpu_nr_slots - 1])) {
- chunk = pcpu_create_chunk(0);
+ chunk = pcpu_create_chunk(pcpu_gfp);
if (!chunk) {
err = "failed to allocate new chunk";
goto fail;
@@ -1455,7 +1453,7 @@ area_found:
page_start, page_end) {
WARN_ON(chunk->immutable);
- ret = pcpu_populate_chunk(chunk, rs, re, 0);
+ ret = pcpu_populate_chunk(chunk, rs, re, pcpu_gfp);
spin_lock_irqsave(&pcpu_lock, flags);
if (ret) {
@@ -1576,7 +1574,7 @@ void __percpu *__alloc_reserved_percpu(size_t size, size_t align)
static void pcpu_balance_workfn(struct work_struct *work)
{
/* gfp flags passed to underlying allocators */
- const gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
+ const gfp_t gfp = GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN;
LIST_HEAD(to_free);
struct list_head *free_head = &pcpu_slot[pcpu_nr_slots - 1];
struct pcpu_chunk *chunk, *next;