Re: [Crash-utility] [PATCH] Add support for SLAB OBJFREELIST_SLAB.

That was quick. Thanks Dave!

On Fri, Dec 2, 2016 at 10:59 AM, Dave Anderson <anderson(a)redhat.com&gt; wrote: > > > ----- Original Message ----- > > In this mode, the freelist can be an object and if the slab is full, > > there is no freelist. On the next free, an object is recycled to be used > > as the freelist but not clean-up. This change will go through only > > known freed objects to prevent errors of wrong/corrupt freelist entries. > > > > Related to the linux kernel commit: b03a017bebc403d40aa53a092e79b3 > 020786537d. > > Thanks Thomas -- the patch queued for crash-7.1.8: > > https://github.com/crash-utility/crash/commit/ > 59fbaf3e4b030b150f750f5b0ac7dfc3eafaa78f > > Dave > > > > --- > > memory.c | 30 ++++++++++++++++++++++++------ > > 1 file changed, 24 insertions(+), 6 deletions(-) > > > > diff --git a/memory.c b/memory.c > > index 4eac413..774d090 100644 > > --- a/memory.c > > +++ b/memory.c > > @@ -9880,6 +9880,7 @@ ignore_cache(struct meminfo *si, char *name) > > #define SLAB_MAGIC_DESTROYED 0xB2F23C5AUL /* slab has been > destroyed > > */ > > > > #define SLAB_CFLGS_BUFCTL 0x020000UL /* bufctls in own cache > */ > > +#define SLAB_CFLGS_OBJFREELIST 0x40000000UL /* Freelist as an > object */ > > > > #define KMEM_SLAB_ADDR (1) > > #define KMEM_BUFCTL_ADDR (2) > > @@ -12439,11 +12440,13 @@ gather_slab_free_list_percpu(struct meminfo > *si) > > static void > > gather_slab_free_list_slab_overload_page(struct meminfo *si) > > { > > - int i, active; > > + int i, active, start_offset; > > ulong obj, objnr, cnt, freelist; > > unsigned char *ucharptr; > > unsigned short *ushortptr; > > unsigned int *uintptr; > > + unsigned int cache_flags, overload_active; > > + ulong slab_overload_page; > > > > if (CRASHDEBUG(1)) > > fprintf(fp, "slab page: %lx active: %ld si->c_num: %ld\n", > > @@ -12452,12 +12455,19 @@ gather_slab_free_list_slab_ > overload_page(struct > > meminfo *si) > > if (si->s_inuse == si->c_num ) > > return; > > > > - readmem(si->slab - OFFSET(page_lru) + OFFSET(page_freelist), > > + slab_overload_page = si->slab - OFFSET(page_lru); > > + readmem(slab_overload_page + OFFSET(page_freelist), > > KVADDR, &freelist, sizeof(void *), "page freelist", > > FAULT_ON_ERROR); > > readmem(freelist, KVADDR, si->freelist, > > si->freelist_index_size * si->c_num, > > "freelist array", FAULT_ON_ERROR); > > + readmem(si->cache+OFFSET(kmem_cache_s_flags), > > + KVADDR, &cache_flags, sizeof(uint), > > + "kmem_cache_s flags", FAULT_ON_ERROR); > > + readmem(slab_overload_page + OFFSET(page_active), > > + KVADDR, &overload_active, sizeof(uint), > > + "active", FAULT_ON_ERROR); > > > > BNEG(si->addrlist, sizeof(ulong) * (si->c_num+1)); > > cnt = objnr = 0; > > @@ -12466,14 +12476,22 @@ gather_slab_free_list_slab_ > overload_page(struct > > meminfo *si) > > uintptr = NULL; > > active = si->s_inuse; > > > > + /* > > + * On an OBJFREELIST slab, the object might have been recycled > > + * and everything before the active count can be random data. > > + */ > > + start_offset = 0; > > + if (cache_flags & SLAB_CFLGS_OBJFREELIST) > > + start_offset = overload_active; > > + > > switch (si->freelist_index_size) > > { > > - case 1: ucharptr = (unsigned char *)si->freelist; break; > > - case 2: ushortptr = (unsigned short *)si->freelist; break; > > - case 4: uintptr = (unsigned int *)si->freelist; break; > > + case 1: ucharptr = (unsigned char *)si->freelist + start_offset; > break; > > + case 2: ushortptr = (unsigned short *)si->freelist + start_offset; > break; > > + case 4: uintptr = (unsigned int *)si->freelist + start_offset; > break; > > } > > > > - for (i = 0; i < si->c_num; i++) { > > + for (i = start_offset; i < si->c_num; i++) { > > switch (si->freelist_index_size) > > { > > case 1: objnr = (ulong)*ucharptr++; break; > > -- > > 2.8.0.rc3.226.g39d4020 > > > > -- > > Crash-utility mailing list > > Crash-utility(a)redhat.com > > https://www.redhat.com/mailman/listinfo/crash-utility > > > -- Thomas