> On Tue, 5 Nov 2019, Jan Hubicka wrote: > > > Hi, > > looking into malloc overhead I noticed that we do a lot of small > > allocations to hold file names comming from location info. This patch > > puts it into an obstack so it interleaves memory allocated by scc_hash > > less frequently. > > (Still we end up interleaving 64k pages which are permanent - in fact > > this table seems to leak from WPA and temporary during stream in) > > > > Bootstrapped/regtested x86_64-linux. OK? > > I think the obstack deserves a big fat comment that it cannot be > reclaimed since the linemap retains permanent pointers into it. > That also suggests to put the string_slot into a separate obstack
The hasher is sort of ethernal, too, since at any time we want to be able to load more from input streams, so we can not really free it. Well, I guess just prior streaming we can, so I will split it. > or better, make the hasher (and other string_slot hashers) > embed the string_slot struct in the hash? We'd save an allocation > everywhere. Well, if we want to free hasher, then we want to keep string separate + comment on obstack, right? I sill update patch tonight. Honza > > Richard. > > > Honza > > > > * lto-streamer-in.c (file_name_obstack): New obstack. > > (canon_file_name): Use it. > > (lto_reader_init): Initialize it. > > Index: lto-streamer-in.c > > =================================================================== > > --- lto-streamer-in.c (revision 277796) > > +++ lto-streamer-in.c (working copy) > > @@ -57,6 +57,7 @@ freeing_string_slot_hasher::remove (valu > > > > /* The table to hold the file names. */ > > static hash_table<freeing_string_slot_hasher> *file_name_hash_table; > > +static struct obstack file_name_obstack; > > > > > > /* Check that tag ACTUAL has one of the given values. NUM_TAGS is the > > @@ -113,8 +114,9 @@ canon_file_name (const char *string) > > char *saved_string; > > struct string_slot *new_slot; > > > > - saved_string = (char *) xmalloc (len + 1); > > - new_slot = XCNEW (struct string_slot); > > + saved_string = XOBNEWVEC (&file_name_obstack, char, len + 1); > > + new_slot = XOBNEWVAR (&file_name_obstack, > > + struct string_slot, sizeof (struct string_slot)); > > memcpy (saved_string, string, len + 1); > > new_slot->s = saved_string; > > new_slot->len = len; > > @@ -1723,6 +1725,7 @@ lto_reader_init (void) > > lto_streamer_init (); > > file_name_hash_table > > = new hash_table<freeing_string_slot_hasher> (37); > > + gcc_obstack_init (&file_name_obstack); > > } > > > > > > > > -- > Richard Biener <rguent...@suse.de> > SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg, > Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)
