After reviewing the hsearch code in glibc, performance
will almost certainly benefit from abandoning a strcmp
approach in favor of hashing, just like that <vmstat>.
[ As an aside, now having struggled toward that goal ]
[ of opaqueness & making our API as user friendly as ]
[ possible, haven't we earned the rights to evaluate ]
[ other implementations? For example, GNU's hsearch? ]
[ We expose none of our 'info' struct details to the ]
[ users, but GNU exposes their 'hsearch_data' thingy ]
[ right there in <search.h>. But worse, they require ]
[ the user to zero it out before 1st use. Jeeze, you ]
[ mean that a function called hcreate_r could not do ]
[ its own memset? Aw, come on GNU! What's with that? ]
Signed-off-by: Jim Warner <james.warner@comcast.net>
With the dust now settling on all those 3rd generation
upgrades, this patch tries to provide some consistency
among the separate modules involved. Someday we should
consider a 4th generation where all redundant code has
been removed and isolated in a new shared source file.
Following is a summary of significant changes (if any)
to each of these now upgraded 3rd gen library modules.
<meminfo> ............................................
. strictly formatting/comment changes, code unaffected
<pids> ...............................................
. replaced a local mkSTR macro with existing STRINGIFY
. added fetch narrative explaining duplicate addresses
<slabinfo> ...........................................
. rearranged some free logic for procps_slabinfo_unref
. added fetch narrative explaining duplicate addresses
<stat> ...............................................
. added #define ENFORCE_LOGICAL, just as in <slabinfo>
. replaced a local mkSTR macro with existing STRINGIFY
. alphabetized the function declarations in the header
<vmstat> .............................................
. made one coverity concession with read_vmstat_failed
[ several of these changes may reflect this author's ]
[ continuing pursuit of an unreasonable goal -- that ]
[ of a 'perfect' (plus 'pretty') C language program! ]
Signed-off-by: Jim Warner <james.warner@comcast.net>
This patch was prompted through work on the <slabinfo>
upgrade from 2nd gen to 3rd. And while this assignment
caused no real harm, it most certainly was misleading.
[ plus add a couple of overlooked #undef directives! ]
Signed-off-by: Jim Warner <james.warner@comcast.net>
When this interface was normalized/standardized, under
the commit referenced below, the parameters were never
validated in the 'get' function. Let's plug that hole.
Reference(s):
commit 407f1b71de
Signed-off-by: Jim Warner <james.warner@comcast.net>
Because of the vast quantities of virtual memory which
may be allocated, it initially seemed like a good idea
to provide for a widest possible range through the use
of a 'ull_int' result type. However, on second thought
the implementation was a bit flawed for these reasons:
. that underlying meminfo_data variable 'VmallocTotal'
is 'unsigned long' not a required 'unsigned long long'
. there wasn't a convenient way to value it since each
variable was set with a strtoul() call, not strtoull()
So this patch will standardize on the 'ul_int' results
type (and reduce the associated delta to 's_int' too).
For now, we'll rely on protections under a 64-bit arch
where a 'ull_int' & 'ul_int' yield identical capacity.
Signed-off-by: Jim Warner <james.warner@comcast.net>
When the code for DELTA values (among other stuff) was
stolen from the recently revised <stat> interface, the
concept of ever growing values was propagated too. But
here we must manage both growing and shrinking values.
Thus former protections against a negative delta don't
have any place in this module and are hereby banished.
Signed-off-by: Jim Warner <james.warner@comcast.net>
Thus function returns a pointer, not an int, so if there is
an error return NULL and not -errno.
proc/meminfo.c: In function ‘procps_meminfo_select’:
proc/meminfo.c:994:20: warning: return makes pointer from integer
without a cast [-Wint-conversion]
return -ENOMEM;
References:
commit 407f1b71de
This represents the refinement of this interface after
the <stat> API was redesigned. We now follow a pattern
of 'get' for single item retrieval & 'select' for when
multiple items are desired, with just 1 function call.
And again following the <stat> lead this interface now
provides for delta values encompassing most items. The
reason I went cuckoo nuts with those deltas is because
they are essentially free. At the cost of a little RAM
and just one memcpy there's no other price to be paid.
Signed-off-by: Jim Warner <james.warner@comcast.net>
Not sure how this one has gone unnoticed until now but
with valgrind's help it's going bye-bye lickety-split.
Reference(s):
==26533== Conditional jump or move depends on uninitialised value(s)
==26533== at 0x4E4082B: procps_meminfo_stack_fill (meminfo.c:408)
Signed-off-by: Jim Warner <james.warner@comcast.net>
This commit just corrects the oversight wherein 'item'
was being employed when 'these' was actually intended.
Also, it trades some 'item' use for a more descriptive
input parameter which henceforth is known as a 'dest'.
And, there was one leftover 'next' pointer eliminated.
Finally, some logic was made a tad less dependent upon
enumerator names and a few comments were also updated.
Signed-off-by: Jim Warner <james.warner@comcast.net>
With the new perspective on potential uses of a 'noop'
enumerator (or whatever we decide to call it) there is
no longer a need to provide for any extra 'user' space
in the stack header structures used by slab & meminfo.
Signed-off-by: Jim Warner <james.warner@comcast.net>
In addition to that text shown below the line which is
common to several commit messages, this patch contains
the following additional change without an API impact:
. The #include header files are ordered alphabetically
now, with all those <sys/??> types separately grouped.
------------------------------------------------------
. The former 'chains' have now become 'stacks' without
the 'next' pointer in each result struct. The pointers
initially seemed to offer some flexibility with memory
allocations and benefits for the library access logic.
However, user access was always via displacement and a
a statically allocated chain was cumbersome to define.
. An enumerator ending in '_noop' will no longer serve
as a fencepost delimiter. Rather, it has become a much
more important and flexible user oriented tool. Adding
one or more such 'items' in any items list passed into
the library becomes the means of extending the 'stack'
to also include user (not just library) data. Any such
data is guaranteed to never be altered by the library.
. Anticipating PID support, where many different types
must be represented in a result structure, we'll adopt
a common naming standard. And, while not every results
structure currently needs to reflect disparate types a
union will be employed so the same dot qualifier ('.')
can be used consistently when accessing all such data.
Signed-off-by: Jim Warner <james.warner@comcast.net>
With a little help from smatch, this commit eliminates
some inappropriate code. Also some programmer comments
were (barely) improved (i hope) in some small measure.
Reference(s):
smatch: 406 procps_meminfo_chain_fill() warn: variable dereferenced before check 'chain' (see line 403)
Signed-off-by: Jim Warner <james.warner@comcast.net>
An earlier approach to meminfo chaining, referenced in
the patch shown below, represents the first baby steps
toward the goal of some generalized approach with PIDs
processing. However, statically allocating a chain for
each task or thread is totally impractical. And, while
a single chain could serve all PIDs, that would mean a
separate call to our library for each running process.
This commit is intended as the next evolutionary step,
dynamically allocating some 'result' chains to contain
as many or as few 'items' as a caller wishes. In other
words, holding only those 'items' of current interest.
This is the kind of service useful for both top and ps
programs if we finally get around to /proc/<PID> data.
Reference(s):
commit c3fd7473c5
Signed-off-by: Jim Warner <james.warner@comcast.net>
The earlier attempt at protecting these functions from
already freed memory worked just fine until the memory
was, in fact, reused by the OS. At that point, the ref
count would most likely fail an existing a test for 0.
So this commit will take control of the 'info' pointer
and force it to NULL when a reference count reaches 0.
Plus, since it makes little sense returning an address
that a caller already has, henceforth we will return a
reference count out of the 'ref' and 'unref functions.
Reference(s):
commit 74beff80ff
Signed-off-by: Jim Warner <james.warner@comcast.net>
Since we are not using a higher level standard C fopen
all of the read requests were made signal sensitive as
that can result in a 'temporarily' failed i/o request.
Also, protection against some user calling the 'unref'
function on already free memory has been incorporated.
This will protect us from some nasty 'Abort' surprise.
Signed-off-by: Jim Warner <james.warner@comcast.net>
If a caller chooses to reduce the overhead of repeated
function calls, this commit provides for acquiring all
the desired information in just a single library call.
Signed-off-by: Jim Warner <james.warner@comcast.net>
This patch fills in some missing fields which have top
dependencies. Additionally, I've tried to mirror those
calculations Jaromir added for release 3.3.10. The one
calculation that remains missing is 'available' memory
for some kernels. For this API, we'll use a fall-back.
Lastly the lxc safeguards which were recently added to
the old procps library were incorporated here as well.
Signed-off-by: Jim Warner <james.warner@comcast.net>
This patch mostly just eliminates darn tab characters.
Plus the library function declarations and definitions
have been standardized. Most visibly, the input params
now have all been indented on their own separate line.
Signed-off-by: Jim Warner <james.warner@comcast.net>
Created new set of functions for meminfo related calls. Liked the
format of that better so changed vmstat around so the look similar.
Missed the makefile change for uptime so added it in now.
