From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: linux-kernel@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Will Deacon <will@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
"Paul E . McKenney" <paulmck@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Matthew Wilcox <willy@infradead.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Minchan Kim <minchan@kernel.org>, Nitin Gupta <ngupta@vflare.org>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Subject: [PATCH v3 6/7] zram: Allocate struct zcomp_strm as per-CPU memory
Date: Wed, 27 May 2020 22:11:18 +0200 [thread overview]
Message-ID: <20200527201119.1692513-7-bigeasy@linutronix.de> (raw)
In-Reply-To: <20200527201119.1692513-1-bigeasy@linutronix.de>
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.
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
drivers/block/zram/zcomp.c | 41 +++++++++++++++-----------------------
drivers/block/zram/zcomp.h | 2 +-
2 files changed, 17 insertions(+), 26 deletions(-)
diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
index 1a8564a79d8dc..912e3e63d8a09 100644
--- a/drivers/block/zram/zcomp.c
+++ b/drivers/block/zram/zcomp.c
@@ -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;
diff --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h
index 1806475b919df..72c2ee4d843ed 100644
--- a/drivers/block/zram/zcomp.h
+++ b/drivers/block/zram/zcomp.h
@@ -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;
};
--
2.27.0.rc0
next prev parent reply other threads:[~2020-05-27 20:11 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-27 20:11 [PATCH v3 0/7] Introduce local_lock() Sebastian Andrzej Siewior
2020-05-27 20:11 ` [PATCH v3 1/7] locking: " Sebastian Andrzej Siewior
2020-06-01 9:52 ` [tip: locking/core] " tip-bot2 for Thomas Gleixner
2020-05-27 20:11 ` [PATCH v3 2/7] radix-tree: Use local_lock for protection Sebastian Andrzej Siewior
2020-06-01 9:52 ` [tip: locking/core] " tip-bot2 for Sebastian Andrzej Siewior
2020-05-27 20:11 ` [PATCH v3 3/7] mm/swap: " Sebastian Andrzej Siewior
2020-06-01 9:52 ` [tip: locking/core] " tip-bot2 for Ingo Molnar
2020-05-27 20:11 ` [PATCH v3 4/7] squashfs: make use of local lock in multi_cpu decompressor Sebastian Andrzej Siewior
2020-06-01 9:52 ` [tip: locking/core] squashfs: Make " tip-bot2 for Julia Cartwright
2020-05-27 20:11 ` [PATCH v3 5/7] connector/cn_proc: Protect send_msg() with a local lock Sebastian Andrzej Siewior
2020-06-01 9:52 ` [tip: locking/core] " tip-bot2 for Mike Galbraith
2020-05-27 20:11 ` Sebastian Andrzej Siewior [this message]
2020-05-29 20:51 ` [PATCH v3 6/7] zram: Allocate struct zcomp_strm as per-CPU memory Minchan Kim
2020-06-01 9:52 ` [tip: locking/core] " tip-bot2 for Sebastian Andrzej Siewior
2020-05-27 20:11 ` [PATCH v3 7/7] zram: Use local lock to protect per-CPU data Sebastian Andrzej Siewior
2020-05-29 20:57 ` Minchan Kim
2020-06-01 9:52 ` [tip: locking/core] " tip-bot2 for Mike Galbraith
2020-10-19 1:52 ` [PATCH v3 7/7] " Yu Zhao
2020-10-19 2:33 ` Hugh Dickins
2020-10-19 2:46 ` Mike Galbraith
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