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Message-Id: <1617140178-8773-35-git-send-email-anthony.yznaga@oracle.com>
Date: Tue, 30 Mar 2021 14:36:09 -0700
From: Anthony Yznaga <anthony.yznaga@...cle.com>
To: linux-mm@...ck.org, linux-kernel@...r.kernel.org
Cc: willy@...radead.org, corbet@....net, tglx@...utronix.de,
mingo@...hat.com, bp@...en8.de, x86@...nel.org, hpa@...or.com,
dave.hansen@...ux.intel.com, luto@...nel.org, peterz@...radead.org,
rppt@...nel.org, akpm@...ux-foundation.org, hughd@...gle.com,
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nathan@...nel.org, terrelln@...com, vincenzo.frascino@....com,
martin.b.radev@...il.com, andreyknvl@...gle.com,
daniel.kiper@...cle.com, rafael.j.wysocki@...el.com,
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steven.sistare@...cle.com, linux-fsdevel@...r.kernel.org,
linux-doc@...r.kernel.org, kexec@...ts.infradead.org
Subject: [RFC v2 34/43] shmem: PKRAM: multithread preserving and restoring shmem pages
Improve performance by multithreading the work to preserve and restore
shmem pages.
When preserving pages each thread saves non-overlapping ranges of a file
to a pkram_obj until all pages are preserved.
When restoring pages each thread loads pages using a local pkram_access.
Signed-off-by: Anthony Yznaga <anthony.yznaga@...cle.com>
---
mm/shmem_pkram.c | 94 +++++++++++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 89 insertions(+), 5 deletions(-)
diff --git a/mm/shmem_pkram.c b/mm/shmem_pkram.c
index e52722b3a709..354c2b58962c 100644
--- a/mm/shmem_pkram.c
+++ b/mm/shmem_pkram.c
@@ -115,6 +115,7 @@ static int save_file_content_range(struct pkram_access *pa,
}
struct shmem_pkram_arg {
+ int *error;
struct pkram_stream *ps;
struct address_space *mapping;
struct mm_struct *mm;
@@ -137,6 +138,16 @@ static int get_save_range(unsigned long max, atomic64_t *next, unsigned long *st
return 0;
}
+/* Completion tracking for save_file_content_thr() threads */
+static atomic_t pkram_save_n_undone;
+static DECLARE_COMPLETION(pkram_save_all_done_comp);
+
+static inline void pkram_save_report_one_done(void)
+{
+ if (atomic_dec_and_test(&pkram_save_n_undone))
+ complete(&pkram_save_all_done_comp);
+}
+
static int do_save_file_content(struct pkram_stream *ps,
struct address_space *mapping,
atomic64_t *next)
@@ -160,11 +171,40 @@ static int do_save_file_content(struct pkram_stream *ps,
return ret;
}
-static int save_file_content(struct pkram_stream *ps, struct address_space *mapping)
+static int save_file_content_thr(void *data)
{
- struct shmem_pkram_arg arg = { ps, mapping, NULL, ATOMIC64_INIT(0) };
-
- return do_save_file_content(arg.ps, arg.mapping, &arg.next);
+ struct shmem_pkram_arg *arg = data;
+ int ret;
+
+ ret = do_save_file_content(arg->ps, arg->mapping, &arg->next);
+ if (ret && !*arg->error)
+ *arg->error = ret;
+
+ pkram_save_report_one_done();
+ return 0;
+}
+
+static int shmem_pkram_max_threads = 16;
+
+static int save_file_content(struct pkram_stream *ps, struct address_space *mapping)
+ {
+ int err = 0;
+ struct shmem_pkram_arg arg = { &err, ps, mapping, NULL, ATOMIC64_INIT(0) };
+ unsigned int thr, nr_threads;
+
+ nr_threads = num_online_cpus() - 1;
+ nr_threads = clamp_val(shmem_pkram_max_threads, 1, nr_threads);
+
+ if (nr_threads == 1)
+ return do_save_file_content(arg.ps, arg.mapping, &arg.next);
+
+ atomic_set(&pkram_save_n_undone, nr_threads);
+ for (thr = 0; thr < nr_threads; thr++)
+ kthread_run(save_file_content_thr, &arg, "pkram_save%d", thr);
+
+ wait_for_completion(&pkram_save_all_done_comp);
+
+ return err;
}
static int save_file(struct dentry *dentry, struct pkram_stream *ps)
@@ -275,7 +315,17 @@ int shmem_save_pkram(struct super_block *sb)
return err;
}
-static int load_file_content(struct pkram_stream *ps, struct address_space *mapping, struct mm_struct *mm)
+/* Completion tracking for load_file_content_thr() threads */
+static atomic_t pkram_load_n_undone;
+static DECLARE_COMPLETION(pkram_load_all_done_comp);
+
+static inline void pkram_load_report_one_done(void)
+{
+ if (atomic_dec_and_test(&pkram_load_n_undone))
+ complete(&pkram_load_all_done_comp);
+}
+
+static int do_load_file_content(struct pkram_stream *ps, struct address_space *mapping, struct mm_struct *mm)
{
PKRAM_ACCESS(pa, ps, pages);
unsigned long index;
@@ -296,6 +346,40 @@ static int load_file_content(struct pkram_stream *ps, struct address_space *mapp
return err;
}
+static int load_file_content_thr(void *data)
+{
+ struct shmem_pkram_arg *arg = data;
+ int ret;
+
+ ret = do_load_file_content(arg->ps, arg->mapping, arg->mm);
+ if (ret && !*arg->error)
+ *arg->error = ret;
+
+ pkram_load_report_one_done();
+ return 0;
+}
+
+static int load_file_content(struct pkram_stream *ps, struct address_space *mapping, struct mm_struct *mm)
+{
+ int err = 0;
+ struct shmem_pkram_arg arg = { &err, ps, mapping, mm };
+ unsigned int thr, nr_threads;
+
+ nr_threads = num_online_cpus() - 1;
+ nr_threads = clamp_val(shmem_pkram_max_threads, 1, nr_threads);
+
+ if (nr_threads == 1)
+ return do_load_file_content(ps, mapping, mm);
+
+ atomic_set(&pkram_load_n_undone, nr_threads);
+ for (thr = 0; thr < nr_threads; thr++)
+ kthread_run(load_file_content_thr, &arg, "pkram_load%d", thr);
+
+ wait_for_completion(&pkram_load_all_done_comp);
+
+ return err;
+}
+
static int load_file(struct dentry *parent, struct pkram_stream *ps,
char *buf, size_t bufsize)
{
--
1.8.3.1
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