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zram: Allocate struct zcomp_strm as per-CPU memory

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zcomp::stream is a per-CPU pointer, pointing to struct zcomp_strm
which contains two pointers. Having struct zcomp_strm allocated
directly as per-CPU memory would avoid one additional memory
allocation and a pointer dereference. This also simplifies the
addition of a local_lock to struct zcomp_strm.

Allocate zcomp::stream directly as per-CPU memory.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20200527201119.1692513-7-bigeasy@linutronix.de
This commit is contained in:
Sebastian Andrzej Siewior 2020-05-27 22:11:18 +02:00 committed by Ingo Molnar
parent 3e92fd7bd2
commit ed19f19256
2 changed files with 17 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

41
drivers/block/zram/zcomp.c
View File

@ -37,19 +37,16 @@ static void zcomp_strm_free(struct zcomp_strm *zstrm)
if (!IS_ERR_OR_NULL(zstrm->tfm))
crypto_free_comp(zstrm->tfm);
free_pages((unsigned long)zstrm->buffer, 1);
kfree(zstrm);
zstrm->tfm = NULL;
zstrm->buffer = NULL;
}
/*
* allocate new zcomp_strm structure with ->tfm initialized by
* backend, return NULL on error
* Initialize zcomp_strm structure with ->tfm initialized by backend, and
* ->buffer. Return a negative value on error.
*/
static struct zcomp_strm *zcomp_strm_alloc(struct zcomp *comp)
static int zcomp_strm_init(struct zcomp_strm *zstrm, struct zcomp *comp)
{
struct zcomp_strm *zstrm = kmalloc(sizeof(*zstrm), GFP_KERNEL);
if (!zstrm)
return NULL;
zstrm->tfm = crypto_alloc_comp(comp->name, 0, 0);
/*
* allocate 2 pages. 1 for compressed data, plus 1 extra for the
@ -58,9 +55,9 @@ static struct zcomp_strm *zcomp_strm_alloc(struct zcomp *comp)
zstrm->buffer = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1);
if (IS_ERR_OR_NULL(zstrm->tfm) || !zstrm->buffer) {
zcomp_strm_free(zstrm);
zstrm = NULL;
return -ENOMEM;
}
return zstrm;
return 0;
}
bool zcomp_available_algorithm(const char *comp)
@ -113,7 +110,7 @@ ssize_t zcomp_available_show(const char *comp, char *buf)
struct zcomp_strm *zcomp_stream_get(struct zcomp *comp)
{
return *get_cpu_ptr(comp->stream);
return get_cpu_ptr(comp->stream);
}
void zcomp_stream_put(struct zcomp *comp)
@ -159,17 +156,13 @@ int zcomp_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)
{
struct zcomp *comp = hlist_entry(node, struct zcomp, node);
struct zcomp_strm *zstrm;
int ret;
if (WARN_ON(*per_cpu_ptr(comp->stream, cpu)))
return 0;
zstrm = zcomp_strm_alloc(comp);
if (IS_ERR_OR_NULL(zstrm)) {
zstrm = per_cpu_ptr(comp->stream, cpu);
ret = zcomp_strm_init(zstrm, comp);
if (ret)
pr_err("Can't allocate a compression stream\n");
return -ENOMEM;
}
*per_cpu_ptr(comp->stream, cpu) = zstrm;
return 0;
return ret;
}
int zcomp_cpu_dead(unsigned int cpu, struct hlist_node *node)
@ -177,10 +170,8 @@ int zcomp_cpu_dead(unsigned int cpu, struct hlist_node *node)
struct zcomp *comp = hlist_entry(node, struct zcomp, node);
struct zcomp_strm *zstrm;
zstrm = *per_cpu_ptr(comp->stream, cpu);
if (!IS_ERR_OR_NULL(zstrm))
zcomp_strm_free(zstrm);
*per_cpu_ptr(comp->stream, cpu) = NULL;
zstrm = per_cpu_ptr(comp->stream, cpu);
zcomp_strm_free(zstrm);
return 0;
}
@ -188,7 +179,7 @@ static int zcomp_init(struct zcomp *comp)
{
int ret;
comp->stream = alloc_percpu(struct zcomp_strm *);
comp->stream = alloc_percpu(struct zcomp_strm);
if (!comp->stream)
return -ENOMEM;

2
drivers/block/zram/zcomp.h
View File

@ -14,7 +14,7 @@ struct zcomp_strm {
/* dynamic per-device compression frontend */
struct zcomp {
struct zcomp_strm * __percpu *stream;
struct zcomp_strm __percpu *stream;
const char *name;
struct hlist_node node;
};