[RFR]8215622: Add dump to file support for jmap histo

[臧琳]

Dear JC,
         Thanks for your comments, I inlined my comments here:
http://cr.openjdk.java.net/~xiaofeya/8215622/webrev.01/src/hotspot/share/services/attachListener.cpp.udiff.html
  - Should we do like the rest of the file and declare variables when needed instead of doing them all at the start?
    --- (Lin) I will do that in next webrev.
  - Should the method return JNI_ERR if the file cannot be created (because if not, then why fail if no file is passed at all?)
   --- (Lin) The logic is that when user use “-file=<filename>”, the file must be created successful, otherwise the “-file=” not work, which break user’s expection, so it fail here. If user not specify “-file=”, it indicate that user not expect to dump to file, so the outputStream will be used. Do you think it is reasonable?

The bigger issue I see is the passing of NULL for a filename, why do we not do things where you just really pass "-file=<file>" to the attachListener.cpp and handle the parsing there?; it would then make more sense to me: we either pass "-file=<file>" or not but we no longer have a "maybe there is or not a file, so maybe there is a NULL there".
---(Lin) This is similar with what I have done in webrev00, but I think maybe processing arguments in JMap.java is more reasonable, I think logically, it is JMap’s responsibility to parsed it’s command line arguments, and then pass it to attachListener. The attachListener just hearing from the socket and get command and parsed arguments. And one more reason maybe that in java it is easy to get the canonical path from the API getCanonicalPath(), which I guess maybe a little complicate to do it cross platform in attachListener.cpp.

All other comments will be handled in the next webrev. Thanks a lot for your review and suggestions.

Cheers,
Lin


From: JC Beyler <jcbeyler at google.com>
Sent: Wednesday, January 9, 2019 1:42 AM
To: 臧琳 <zanglin5 at jd.com>
Cc: Hohensee, Paul <hohensee at amazon.com>; serviceability-dev at openjdk.java.net
Subject: Re: [RFR]8215622: Add dump to file support for jmap histo

Hi Lin,

I have a few nits:
  http://cr.openjdk.java.net/~xiaofeya/8215622/webrev.01/src/jdk.attach/aix/classes/sun/tools/attach/VirtualMachineImpl.java.udiff.html
  http://cr.openjdk.java.net/~xiaofeya/8215622/webrev.01/src/jdk.attach/linux/classes/sun/tools/attach/VirtualMachineImpl.java.udiff.html
  http://cr.openjdk.java.net/~xiaofeya/8215622/webrev.01/src/jdk.attach/macosx/classes/sun/tools/attach/VirtualMachineImpl.java.udiff.html

You could fix the spaces arount the for loop you changed:

+            for (int i=0; i<4; i++) {
to

+            for (int i = 0; i < 4; i++) {


http://cr.openjdk.java.net/~xiaofeya/8215622/webrev.01/src/hotspot/share/services/attachListener.cpp.udiff.html
  - Should we do like the rest of the file and declare variables when needed instead of doing them all at the start?
  - Should the method return JNI_ERR if the file cannot be created (because if not, then why fail if no file is passed at all?)

http://cr.openjdk.java.net/~xiaofeya/8215622/webrev.01/src/jdk.jcmd/share/classes/sun/tools/jmap/JMap.java.udiff.html
+            filename = opt.substring(5);
+            if (filename != null) {
   -> I don't see how filename can be null here
  -> same filename could just be declared in the if



+            } else if (subopt.startsWith("file=")) {
+                filename = parseFileName(subopt);

-> So actually you are testing twice if the string starts with "file=", maybe remove the one in the method?

-> in the option string printouts, you don't specify that all is an option as well, is that normal?


The bigger issue I see is the passing of NULL for a filename, why do we not do things where you just really pass "-file=<file>" to the attachListener.cpp and handle the parsing there?; it would then make more sense to me: we either pass "-file=<file>" or not but we no longer have a "maybe there is or not a file, so maybe there is a NULL there".

Thanks,
Jc

On Mon, Jan 7, 2019 at 2:11 AM 臧琳 <zanglin5 at jd.com<mailto:zanglin5 at jd.com>> wrote:

Hi Paul,
    I think it is not necessary to have a loop for argument processing, since there is not so much arguments to handle.
   And I made a new webrev http://cr.openjdk.java.net/~xiaofeya/8215622/webrev.01/

Hi All,
    May I also ask your help for reviewing this webrev?
    webrev http://cr.openjdk.java.net/~xiaofeya/8215622/webrev.01/
    Bug: https://bugs.openjdk.java.net/browse/JDK-8215622

Thanks!
Lin

________________________________
发件人: serviceability-dev <serviceability-dev-bounces at openjdk.java.net<mailto:serviceability-dev-bounces at openjdk.java.net>> 代表 臧琳 <zanglin5 at jd.com<mailto:zanglin5 at jd.com>>
发送时间: 2019年1月3日 10:21
收件人: Hohensee, Paul; serviceability-dev at openjdk.java.net<mailto:serviceability-dev at openjdk.java.net>
主题: [发件地址伪造,恶意邮件,勿点] RE: [RFR]8215622: Add dump to file support for jmap histo


Dear Paul,

       Thanks a lot for your review! I am trying to remend the patch

       One problem is that in future, I will add more options for histo, such as “parallel”, “incremental”.

so do you thinking option processing with loop in heap_inspection() in attachListener.cpp would

be more reasonable than the “if else” ?

Thanks



BRs,

Lin







From: Hohensee, Paul <hohensee at amazon.com<mailto:hohensee at amazon.com>>
Sent: Saturday, December 29, 2018 3:54 AM
To: 臧琳 <zanglin5 at jd.com<mailto:zanglin5 at jd.com>>; serviceability-dev at openjdk.java.net<mailto:serviceability-dev at openjdk.java.net>
Subject: Re: [RFR]8215622: Add dump to file support for jmap histo



Update the copyright dates to 2019 please, since this won’t get pushed until then.



In JMap.java, I’d emulate dump() and use



        String filename = null;

        String subopts[] = options.split(",");



        for (String subopt : subopts){

            if (subopt.isEmpty() || subopt.equals("all")) {

                // pass

            } else if (subopt.equals("live")) {

                liveopt = "-live";

            } else if (subopt.startsWith("file=")) {

                // file=<file> - check that <file> is specified

                if (subopt.length() > 5) {

                    filename = subopt.substring(5);

                }

            } else {

              usage(1);

            }

         }



         // get the canonical path - important to avoid just passing

         // a "heap.bin" and having the dump created in the target VM

         // working directory rather than the directory where jmap

         // is executed.

         filename = new File(filename).getCanonicalPath();

         // inspectHeap is not the same as jcmd GC.class_histogram

         executeCommandForPid(pid, "inspectheap", filename, liveopt);



I.e., use an enhanced for loop to scan the array, and duplicate dump()’s executeCommandForPid() argument order, as well as dump()’s “file=<>” check (the code that starts with “if (subopt.startsWith”) and canonicalization. Actually, better to factor the latter out into its own method and use it from both histo() and dump().



The argument checking code in heap_inspection() in attachListener.cpp can be simplified along the lines of dump_heap(). I.e., you don’t need to loop over the argument list. To match up with dump_heap()’s info messages, the info message string at the end should be “Heap inspection file created: %s”.



Thanks,



Paul



From: serviceability-dev <serviceability-dev-bounces at openjdk.java.net<mailto:serviceability-dev-bounces at openjdk.java.net>> on behalf of 臧琳 <zanglin5 at jd.com<mailto:zanglin5 at jd.com>>
Date: Thursday, December 20, 2018 at 11:03 PM
To: "serviceability-dev at openjdk.java.net<mailto:serviceability-dev at openjdk.java.net>" <serviceability-dev at openjdk.java.net<mailto:serviceability-dev at openjdk.java.net>>
Subject: [RFR]8215622: Add dump to file support for jmap histo



Hi All,

       May I ask your help to review this patch for enhance jmap –histo.

It add the “file=<path>” arguments that allow jmap –histo outputs data to file directly.

This patch is also part of the enhancement described in https://bugs.openjdk.java.net/browse/JDK-8214535.



Webrev: http://cr.openjdk.java.net/~xiaofeya/8215622/webrev.00/

Bug: https://bugs.openjdk.java.net/browse/JDK-8215622



Thanks.



BRs,

Lin








--

Thanks,
Jc
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