Re: [RFC v10 01/13] damon/dbgfs: Allow users to set initial monitoring target regions
From: SeongJae Park <hidden>
Date: 2021-01-19 21:36:32
Also in:
linux-mm, lkml
On Wed, 16 Dec 2020 10:42:09 +0100 SeongJae Park [off-list ref] wrote:
quoted hunk ↗ jump to hunk
From: SeongJae Park <redacted> Some 'damon-dbgfs' users would want to monitor only a part of the entire virtual memory address space. The framework users in the kernel space could use '->init_target_regions' callback or even set the regions inside the context struct as they want, but 'damon-dbgfs' users cannot. For the reason, this commit introduces a new debugfs file, 'init_region'. 'damon-dbgfs' users can specify which initial monitoring target address regions they want by writing special input to the file. The input should describe each region in each line in below form: <pid> <start address> <end address> Note that the regions will be updated to cover entire memory mapped regions after 'regions update interval'. If you want the regions to not be updated after the initial setting, you could set the interval as a very long time, say, a few decades. Signed-off-by: SeongJae Park <redacted> --- mm/damon/dbgfs.c | 154 ++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 151 insertions(+), 3 deletions(-)diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c index 06295c986dc3..2f1ec6ebd9f0 100644 --- a/mm/damon/dbgfs.c +++ b/mm/damon/dbgfs.c
[...]
+
+static ssize_t dbgfs_init_regions_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct damon_ctx *ctx = file->private_data;
+ char *kbuf;
+ ssize_t len;
+
+ kbuf = kmalloc(count, GFP_KERNEL);
+ if (!kbuf)
+ return -ENOMEM;
+
+ mutex_lock(&ctx->kdamond_lock);
+ if (ctx->kdamond) {
+ mutex_unlock(&ctx->kdamond_lock);
+ return -EBUSY;Coverity Static Analysis Security Testing (SAST) by Synopsys, Inc. found that above return is missing deallocation of 'kbuf'. I will fix this in the next version.
+ } + + len = sprint_init_regions(ctx, kbuf, count); + mutex_unlock(&ctx->kdamond_lock); + if (len < 0) + goto out; + len = simple_read_from_buffer(buf, count, ppos, kbuf, len); + +out: + kfree(kbuf); + return len; +}
Thanks, SeongJae Park [...]