Bug 74078 – [Qt] Shared memory should use SHM instead of tmpdir

• Status: RESOLVED
• Resolution: FIXED
• Component: WebKit2

[Allan Sandfeld Jensen]

Originally seen as one of the causes of NB#240753

Shared memory uses tmpdir which causes a crash if the filesystem tmpdir resides in fills up. Switching the shared memory implementation from tmpdir to SHM provides a stability and performance improvement.

[Allan Sandfeld Jensen]

Created attachment 118370 [details]
Patch

[Kenneth Rohde Christiansen]

Comment on attachment 118370 [details]
Patch

Looks good

[Allan Sandfeld Jensen]

Created attachment 118377 [details]
Patch

[WebKit Review Bot]

Comment on attachment 118377 [details]
Patch

Rejecting attachment 118377 [details] from commit-queue.

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[WebKit Review Bot]

Comment on attachment 118377 [details]
Patch

Clearing flags on attachment: 118377

Committed r102493: <http://trac.webkit.org/changeset/102493>

[WebKit Review Bot]

All reviewed patches have been landed.  Closing bug.

[Viatcheslav Ostapenko]

(In reply to comment #5)
> (From update of attachment 118377 [details])
> Clearing flags on attachment: 118377
> 
> Committed r102493: <http://trac.webkit.org/changeset/102493>

For me this works only if I add "LIBS += -lrt" to linux-g++* section of api.pri on Ubuntu 11.10 with qt5 11bdb40bfda68291b9767b7908a2ab7dc3b75786 (from last bot update).

[Simon Hausmann]

Comment on attachment 118377 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=118377&action=review

> Source/WebKit2/Platform/unix/SharedMemoryUnix.cpp:125
> +#if PLATFORM(QT)
> +    while ((fileDescriptor = shm_open(tempNameC, O_CREAT | O_CLOEXEC | O_RDWR, S_IRUSR | S_IWUSR)) == -1) {
> +        if (errno != EINTR)
> +            return 0;
> +    }
> +#else
>      while ((fileDescriptor = mkstemp(tempNameC)) == -1) {
>          if (errno != EINTR)
>              return 0;

It's kind of silly that Qt uses shm_open and the others use mkstemp - there is nothing Qt specific here. We should simply be using shm_open/shm_unlink for SharedMemoryUnix.cpp.

[Allan Sandfeld Jensen]

I agree. I only made it QT specific because I didn't have the setup to compile and test for GTK. It should be very easy for a GTK developer to remove the IFDEFs and join the code.

[Simon Hausmann]

(In reply to comment #9)
> I agree. I only made it QT specific because I didn't have the setup to compile and test for GTK. It should be very easy for a GTK developer to remove the IFDEFs and join the code.

I have filed bug #74602 for this. Will upload a patch soon.